Alzheimer's & Cognition

Dementia prevalence is dropping in the United States, new research shows. New data from the Health and Retirement Study, a nationally representative survey, show that the prevalence of dementia among individuals aged 65 and older dropped from 12.2% in 2000 to 8.5% in 2016 – a 30.1% decrease. In men, the prevalence of dementia fell from 10.2% to 7.0%, while for women, it declined from 13.6% to 9.7%, researchers reported. Their finding were published online in PNAS.

The study also revealed that the proportion of college-educated men in the sample increased from 21.5% in 2000 to 33.7% in 2016, while the proportion of college-educated women increased from 12.3% in 2000 to 23% in 2016.

The findings also show a decline in the dementia prevalence in non-Hispanic Black men, which dropped from 17.2% to 9.9%, a decrease of 42.6%. In non-Hispanic White men, dementia declined 9.3% to 6.6%, or 29.0%.

The investigators also found a substantial increase in the level of education between 2000 and 2016. In addition, they found that, among 74- to 84-year-old women in 2000, 29.5% had worked for more than 30 years during their lifetime versus 59.0% in 2016.

The investigators speculated that the decline in dementia prevalence reflects larger socioeconomic changes in the United States as well as prevention strategies to reduce cardiovascular disease.

A person born around 1920, for example, would have had greater exposure to the Great Depression, while someone born in 1936 would have benefited more from the changes in living standards in the years following World War II, they noted.

“There’s a need for more research on the effect of employment on cognitive reserve. It’s plausible that working is good for your mental cognitive abilities,” said study investigator Péter Hudomiet, PhD, from the RAND Corporation, adding that there may also be benefits that extend beyond working years. It’s possible that women’s greater participation in the workforce gives them more chances to establish relationships that in some cases last well into retirement and provide essential social connection. It’s well known that social isolation has a negative impact on cognition.

“It’s plausible that working is good for your mental cognitive abilities,” he added.

The investigators noted that it is beyond the scope of their study to draw definitive conclusions about the causes of the decline, but they observed that positive trends in employment and standard of living make sense. “They would suggest that as schooling levels continue to rise in the U.S. population in younger generations, the prevalence of dementia would continue to decrease.

The investigators report no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Dementia prevalence is dropping in the United States, new research shows. New data from the Health and Retirement Study, a nationally representative survey, show that the prevalence of dementia among individuals aged 65 and older dropped from 12.2% in 2000 to 8.5% in 2016 – a 30.1% decrease. In men, the prevalence of dementia fell from 10.2% to 7.0%, while for women, it declined from 13.6% to 9.7%, researchers reported. Their finding were published online in PNAS.

The study also revealed that the proportion of college-educated men in the sample increased from 21.5% in 2000 to 33.7% in 2016, while the proportion of college-educated women increased from 12.3% in 2000 to 23% in 2016.

The findings also show a decline in the dementia prevalence in non-Hispanic Black men, which dropped from 17.2% to 9.9%, a decrease of 42.6%. In non-Hispanic White men, dementia declined 9.3% to 6.6%, or 29.0%.

The investigators also found a substantial increase in the level of education between 2000 and 2016. In addition, they found that, among 74- to 84-year-old women in 2000, 29.5% had worked for more than 30 years during their lifetime versus 59.0% in 2016.

The investigators speculated that the decline in dementia prevalence reflects larger socioeconomic changes in the United States as well as prevention strategies to reduce cardiovascular disease.

A person born around 1920, for example, would have had greater exposure to the Great Depression, while someone born in 1936 would have benefited more from the changes in living standards in the years following World War II, they noted.

“There’s a need for more research on the effect of employment on cognitive reserve. It’s plausible that working is good for your mental cognitive abilities,” said study investigator Péter Hudomiet, PhD, from the RAND Corporation, adding that there may also be benefits that extend beyond working years. It’s possible that women’s greater participation in the workforce gives them more chances to establish relationships that in some cases last well into retirement and provide essential social connection. It’s well known that social isolation has a negative impact on cognition.

“It’s plausible that working is good for your mental cognitive abilities,” he added.

The investigators noted that it is beyond the scope of their study to draw definitive conclusions about the causes of the decline, but they observed that positive trends in employment and standard of living make sense. “They would suggest that as schooling levels continue to rise in the U.S. population in younger generations, the prevalence of dementia would continue to decrease.

The investigators report no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Dementia prevalence is dropping in the United States, new research shows. New data from the Health and Retirement Study, a nationally representative survey, show that the prevalence of dementia among individuals aged 65 and older dropped from 12.2% in 2000 to 8.5% in 2016 – a 30.1% decrease. In men, the prevalence of dementia fell from 10.2% to 7.0%, while for women, it declined from 13.6% to 9.7%, researchers reported. Their finding were published online in PNAS.

The study also revealed that the proportion of college-educated men in the sample increased from 21.5% in 2000 to 33.7% in 2016, while the proportion of college-educated women increased from 12.3% in 2000 to 23% in 2016.

The findings also show a decline in the dementia prevalence in non-Hispanic Black men, which dropped from 17.2% to 9.9%, a decrease of 42.6%. In non-Hispanic White men, dementia declined 9.3% to 6.6%, or 29.0%.

The investigators also found a substantial increase in the level of education between 2000 and 2016. In addition, they found that, among 74- to 84-year-old women in 2000, 29.5% had worked for more than 30 years during their lifetime versus 59.0% in 2016.

The investigators speculated that the decline in dementia prevalence reflects larger socioeconomic changes in the United States as well as prevention strategies to reduce cardiovascular disease.

A person born around 1920, for example, would have had greater exposure to the Great Depression, while someone born in 1936 would have benefited more from the changes in living standards in the years following World War II, they noted.

“There’s a need for more research on the effect of employment on cognitive reserve. It’s plausible that working is good for your mental cognitive abilities,” said study investigator Péter Hudomiet, PhD, from the RAND Corporation, adding that there may also be benefits that extend beyond working years. It’s possible that women’s greater participation in the workforce gives them more chances to establish relationships that in some cases last well into retirement and provide essential social connection. It’s well known that social isolation has a negative impact on cognition.

“It’s plausible that working is good for your mental cognitive abilities,” he added.

The investigators noted that it is beyond the scope of their study to draw definitive conclusions about the causes of the decline, but they observed that positive trends in employment and standard of living make sense. “They would suggest that as schooling levels continue to rise in the U.S. population in younger generations, the prevalence of dementia would continue to decrease.

The investigators report no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Among older adults who use the U.S. Supplemental Nutrition Assistance Program (SNAP), rates of memory decline appear to be slower than among those who don’t use the program, new research shows. Researchers assessed the memory function of more than 3,500 persons who used SNAP or did not use SNAP over a period of 20 years. They found that those who didn’t use the food benefits program experienced 2 more years of cognitive aging compared with program users.

Of the 3,555 individuals included in the study, all were eligible to use the benefits, but only 559 did, leaving 2,996 participants who did not take advantage of the program.

Low program participation levels translate into a missed opportunity to prevent dementia, said study investigator Adina Zeki Al Hazzouri, PhD, assistant professor of epidemiology at the Columbia Aging Center at Columbia University Mailman School of Public Health in New York.

She said that prior research has shown that stigma may prevent older Americans from using SNAP. “Educational programs are needed to reduce the stigma that the public holds towards SNAP use,” she said.

Policy change could increase usage among older individuals, Dr. Zeki Al Hazzouri noted. Such changes could include simplifying enrollment and reporting procedures, shortening recertification periods, and increasing benefit levels.

The study was published online in Neurology.
 

Memory preservation

Dr. Zeki Al Hazzouri and her team assessed respondents from the Health and Retirement Study (HRS), a representative sample of Americans aged 50 and older. All respondents who were eligible to participate in SNAP in 1996 were followed every 2 years until 2016.

At each assessment, HRS respondents completed memory tests, including immediate and delayed word recall. For those who were too impaired to complete the interview, proxy informants – typically, their spouses or family members – assessed the memory and cognition of their family members using validated instruments, such as the 16-item Informant Questionnaire for Cognitive Decline.

Investigators used a validated memory function composite score, which is benchmarked against the memory assessments and evaluations of the Aging, Demographics, and Memory Study (ADAMS) cohort.

The team found that compared with nonusers, SNAP users were more likely to be women, Black, and born in the southern United States. They were less likely to be married and had more chronic conditions, such as high blood pressure, diabetes, cancer, heart problems, psychiatric problems, and arthritis.

One important study limitation was that SNAP use was measured only once during the study, the investigators noted. Ideally, Dr. Zeki Al Hazzouri said, future research would examine cumulative SNAP use history and explore the pathways that might account for the association between SNAP use and memory decline.

While findings suggest that there were no significant differences in baseline memory function between SNAP users and nonusers, users experienced approximately 2 fewer years of cognitive aging over a 10-year period than those who didn’t use the program.

Dr. Zeki Al Hazzouri speculated that SNAP benefits may slow cognitive aging by contributing to overall brain health and that, in comparison with nonusers, SNAP users absorb more nutrients, which promote neuronal integrity.

The investigators theorized that SNAP benefits may reduce stress from financial hardship, which has been linked to premature cognitive aging in other research.

“SNAP may also increase the purchasing power and investment in other health preserving behaviors, but also resulting in better access to care, which may in turn result in better disease management and management of risk factors for cognitive function,” the investigators wrote.
 

An underutilized program

In an accompanying editorial, Steven Albert, PhD, Philip B. Hallen Endowed Chair in Community Health and Social Justice at the University of Pittsburgh, noted that in 2020, among households with people aged 50 and older in the United States, more than 9 million Americans experienced food insecurity.

Furthermore, he pointed out, research from 2018 showed that 71% of people aged 60 and older who met income eligibility for SNAP did not participate in the program. “SNAP is an underutilized food security program involving substantial income supplements for older people with low incomes.

“Against the backdrop of so many failures of pharmacotherapy for dementia and the so far inexorable increase in the prevalence of dementia due to population aging, are we missing an opportunity to support cognitive health by failing to enroll the 14 million Americans who are over age 60 and eligible for SNAP but who do not participate?” Dr. Albert asked. He suggested that it would be helpful to determine this through a randomized promotion trial.

The study was funded by the National Institute on Aging. The authors reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Among older adults who use the U.S. Supplemental Nutrition Assistance Program (SNAP), rates of memory decline appear to be slower than among those who don’t use the program, new research shows. Researchers assessed the memory function of more than 3,500 persons who used SNAP or did not use SNAP over a period of 20 years. They found that those who didn’t use the food benefits program experienced 2 more years of cognitive aging compared with program users.

Of the 3,555 individuals included in the study, all were eligible to use the benefits, but only 559 did, leaving 2,996 participants who did not take advantage of the program.

Low program participation levels translate into a missed opportunity to prevent dementia, said study investigator Adina Zeki Al Hazzouri, PhD, assistant professor of epidemiology at the Columbia Aging Center at Columbia University Mailman School of Public Health in New York.

She said that prior research has shown that stigma may prevent older Americans from using SNAP. “Educational programs are needed to reduce the stigma that the public holds towards SNAP use,” she said.

Policy change could increase usage among older individuals, Dr. Zeki Al Hazzouri noted. Such changes could include simplifying enrollment and reporting procedures, shortening recertification periods, and increasing benefit levels.

The study was published online in Neurology.
 

Memory preservation

Dr. Zeki Al Hazzouri and her team assessed respondents from the Health and Retirement Study (HRS), a representative sample of Americans aged 50 and older. All respondents who were eligible to participate in SNAP in 1996 were followed every 2 years until 2016.

At each assessment, HRS respondents completed memory tests, including immediate and delayed word recall. For those who were too impaired to complete the interview, proxy informants – typically, their spouses or family members – assessed the memory and cognition of their family members using validated instruments, such as the 16-item Informant Questionnaire for Cognitive Decline.

Investigators used a validated memory function composite score, which is benchmarked against the memory assessments and evaluations of the Aging, Demographics, and Memory Study (ADAMS) cohort.

The team found that compared with nonusers, SNAP users were more likely to be women, Black, and born in the southern United States. They were less likely to be married and had more chronic conditions, such as high blood pressure, diabetes, cancer, heart problems, psychiatric problems, and arthritis.

One important study limitation was that SNAP use was measured only once during the study, the investigators noted. Ideally, Dr. Zeki Al Hazzouri said, future research would examine cumulative SNAP use history and explore the pathways that might account for the association between SNAP use and memory decline.

While findings suggest that there were no significant differences in baseline memory function between SNAP users and nonusers, users experienced approximately 2 fewer years of cognitive aging over a 10-year period than those who didn’t use the program.

Dr. Zeki Al Hazzouri speculated that SNAP benefits may slow cognitive aging by contributing to overall brain health and that, in comparison with nonusers, SNAP users absorb more nutrients, which promote neuronal integrity.

The investigators theorized that SNAP benefits may reduce stress from financial hardship, which has been linked to premature cognitive aging in other research.

“SNAP may also increase the purchasing power and investment in other health preserving behaviors, but also resulting in better access to care, which may in turn result in better disease management and management of risk factors for cognitive function,” the investigators wrote.
 

An underutilized program

In an accompanying editorial, Steven Albert, PhD, Philip B. Hallen Endowed Chair in Community Health and Social Justice at the University of Pittsburgh, noted that in 2020, among households with people aged 50 and older in the United States, more than 9 million Americans experienced food insecurity.

Furthermore, he pointed out, research from 2018 showed that 71% of people aged 60 and older who met income eligibility for SNAP did not participate in the program. “SNAP is an underutilized food security program involving substantial income supplements for older people with low incomes.

“Against the backdrop of so many failures of pharmacotherapy for dementia and the so far inexorable increase in the prevalence of dementia due to population aging, are we missing an opportunity to support cognitive health by failing to enroll the 14 million Americans who are over age 60 and eligible for SNAP but who do not participate?” Dr. Albert asked. He suggested that it would be helpful to determine this through a randomized promotion trial.

The study was funded by the National Institute on Aging. The authors reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Among older adults who use the U.S. Supplemental Nutrition Assistance Program (SNAP), rates of memory decline appear to be slower than among those who don’t use the program, new research shows. Researchers assessed the memory function of more than 3,500 persons who used SNAP or did not use SNAP over a period of 20 years. They found that those who didn’t use the food benefits program experienced 2 more years of cognitive aging compared with program users.

Of the 3,555 individuals included in the study, all were eligible to use the benefits, but only 559 did, leaving 2,996 participants who did not take advantage of the program.

Low program participation levels translate into a missed opportunity to prevent dementia, said study investigator Adina Zeki Al Hazzouri, PhD, assistant professor of epidemiology at the Columbia Aging Center at Columbia University Mailman School of Public Health in New York.

She said that prior research has shown that stigma may prevent older Americans from using SNAP. “Educational programs are needed to reduce the stigma that the public holds towards SNAP use,” she said.

Policy change could increase usage among older individuals, Dr. Zeki Al Hazzouri noted. Such changes could include simplifying enrollment and reporting procedures, shortening recertification periods, and increasing benefit levels.

The study was published online in Neurology.
 

Memory preservation

Dr. Zeki Al Hazzouri and her team assessed respondents from the Health and Retirement Study (HRS), a representative sample of Americans aged 50 and older. All respondents who were eligible to participate in SNAP in 1996 were followed every 2 years until 2016.

At each assessment, HRS respondents completed memory tests, including immediate and delayed word recall. For those who were too impaired to complete the interview, proxy informants – typically, their spouses or family members – assessed the memory and cognition of their family members using validated instruments, such as the 16-item Informant Questionnaire for Cognitive Decline.

Investigators used a validated memory function composite score, which is benchmarked against the memory assessments and evaluations of the Aging, Demographics, and Memory Study (ADAMS) cohort.

The team found that compared with nonusers, SNAP users were more likely to be women, Black, and born in the southern United States. They were less likely to be married and had more chronic conditions, such as high blood pressure, diabetes, cancer, heart problems, psychiatric problems, and arthritis.

One important study limitation was that SNAP use was measured only once during the study, the investigators noted. Ideally, Dr. Zeki Al Hazzouri said, future research would examine cumulative SNAP use history and explore the pathways that might account for the association between SNAP use and memory decline.

While findings suggest that there were no significant differences in baseline memory function between SNAP users and nonusers, users experienced approximately 2 fewer years of cognitive aging over a 10-year period than those who didn’t use the program.

Dr. Zeki Al Hazzouri speculated that SNAP benefits may slow cognitive aging by contributing to overall brain health and that, in comparison with nonusers, SNAP users absorb more nutrients, which promote neuronal integrity.

The investigators theorized that SNAP benefits may reduce stress from financial hardship, which has been linked to premature cognitive aging in other research.

“SNAP may also increase the purchasing power and investment in other health preserving behaviors, but also resulting in better access to care, which may in turn result in better disease management and management of risk factors for cognitive function,” the investigators wrote.
 

An underutilized program

In an accompanying editorial, Steven Albert, PhD, Philip B. Hallen Endowed Chair in Community Health and Social Justice at the University of Pittsburgh, noted that in 2020, among households with people aged 50 and older in the United States, more than 9 million Americans experienced food insecurity.

Furthermore, he pointed out, research from 2018 showed that 71% of people aged 60 and older who met income eligibility for SNAP did not participate in the program. “SNAP is an underutilized food security program involving substantial income supplements for older people with low incomes.

“Against the backdrop of so many failures of pharmacotherapy for dementia and the so far inexorable increase in the prevalence of dementia due to population aging, are we missing an opportunity to support cognitive health by failing to enroll the 14 million Americans who are over age 60 and eligible for SNAP but who do not participate?” Dr. Albert asked. He suggested that it would be helpful to determine this through a randomized promotion trial.

The study was funded by the National Institute on Aging. The authors reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Exposure to a traffic-related air pollutant significantly increases risk for dementia, new research suggests. Results from a meta-analysis, which included a total of more than 90 million people, showed risk for dementia increased 3% for every 1 mg/m³ rise in fine particulate matter (PM_2.5) exposure.

Particulate matter is a mixture of solid particles and liquid droplets from the burning of fossil fuels and nitrogen oxide, and also produced from road traffic exhaust.

While the research only showed an association between this type of air pollution and dementia risk, the estimates were consistent across the different analyses used.

“It’s rather sobering that there is this 3% relationship between incidence of dementia and the particulate matter and that it is such a precise estimate,” senior investigator Janet Martin, PharmD, MSc, associate professor of anesthesia & perioperative medicine and epidemiology & biostatistics at Western University’s, London, Ont., told this news organization.

The findings were published online in Neurology.
 

Conflicting results in past studies

Air pollution is a known risk factor for dementia, but studies attempting to pinpoint its exact impact have yielded conflicting results.

Researchers analyzed data from 17 studies with a total of 91.4 million individuals, 6% of whom had dementia. In addition to PM_2.5, the investigators also assessed nitrogen oxides, which form smog, nitrogen dioxide, and ozone exposure.

After adjustments for other known risk factors, such as age and gender, results showed that dementia risk increased by 3% for every 1 m³ rise in PM_2.5 exposure (adjusted hazard ratio, 1.03; 95% confidence interval, 1.02-1.05).

The associations between dementia and exposure to nitrogen oxides (HR, 1.05; 95% CI, 0.99-1.13), nitrogen dioxide (HR, 1.03; 95% CI, 1.00-1.07) and ozone (HR, 1.01; 95% CI, 0.91-1.11) did not reach statistical significance. However, the confidence intervals were wide enough that clinical relevance cannot be ruled out, Dr. Martin said.

The study did not examine how or if the duration of PM_2.5 exposure affected dementia risk. In addition, the investigators were not able to identify a threshold above which dementia risk begins to rise.

The Environmental Pollution Agency considers average yearly exposures up to 12 mcg/m³ to be safe. The World Health Organization sets that limit lower, at 5 mcg/m³.

Dr. Martin noted that more studies are needed to explore those issues, as well as the mechanisms by which air pollutants contribute to the pathology of dementia. However, the clear link between fine particulate matter exposure and increased risk emphasizes the need to address air pollution as a modifiable risk factor for dementia.

“The rising tide of dementia is not something we can easily reverse,” Dr. Martin said. “The evidence has been so elusive for how to treat dementia once you have it, so our biggest opportunity is to prevent it.”

Results from a study published earlier in 2022 estimated that rates of dementia will triple worldwide and double in the United States by 2050 unless steps are taking to mitigate risk factors.

Research also suggests that improving air quality PM_2.5 by just 10% results in a 14% decreased risk for dementia.
 

‘Impressive’ pattern

Paul Rosenberg, MD, codirector of the Memory and Alzheimer’s Treatment Center division of geriatric psychiatry at Johns Hopkins University, Baltimore, said that air pollution “is the most prominent environmental risk we’ve found” for dementia. It also “adds to many other lifestyle and comorbidity risks, such as lack of exercise, obesity, depression, hearing loss, etc,” said Dr. Rosenberg, who was not involved with the research.

He noted what was “most impressive” was that in most of the pooled studies, small particulate air pollution was associated with dementia. “The overall pattern is most impressive and the effect sizes quite consistent over most of the studies,” Dr. Rosenberg said.

The meta-analysis was unfunded. Dr. Martin and Dr. Rosenberg reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Exposure to a traffic-related air pollutant significantly increases risk for dementia, new research suggests. Results from a meta-analysis, which included a total of more than 90 million people, showed risk for dementia increased 3% for every 1 mg/m³ rise in fine particulate matter (PM_2.5) exposure.

Particulate matter is a mixture of solid particles and liquid droplets from the burning of fossil fuels and nitrogen oxide, and also produced from road traffic exhaust.

While the research only showed an association between this type of air pollution and dementia risk, the estimates were consistent across the different analyses used.

“It’s rather sobering that there is this 3% relationship between incidence of dementia and the particulate matter and that it is such a precise estimate,” senior investigator Janet Martin, PharmD, MSc, associate professor of anesthesia & perioperative medicine and epidemiology & biostatistics at Western University’s, London, Ont., told this news organization.

The findings were published online in Neurology.
 

Conflicting results in past studies

Air pollution is a known risk factor for dementia, but studies attempting to pinpoint its exact impact have yielded conflicting results.

Researchers analyzed data from 17 studies with a total of 91.4 million individuals, 6% of whom had dementia. In addition to PM_2.5, the investigators also assessed nitrogen oxides, which form smog, nitrogen dioxide, and ozone exposure.

After adjustments for other known risk factors, such as age and gender, results showed that dementia risk increased by 3% for every 1 m³ rise in PM_2.5 exposure (adjusted hazard ratio, 1.03; 95% confidence interval, 1.02-1.05).

The associations between dementia and exposure to nitrogen oxides (HR, 1.05; 95% CI, 0.99-1.13), nitrogen dioxide (HR, 1.03; 95% CI, 1.00-1.07) and ozone (HR, 1.01; 95% CI, 0.91-1.11) did not reach statistical significance. However, the confidence intervals were wide enough that clinical relevance cannot be ruled out, Dr. Martin said.

The study did not examine how or if the duration of PM_2.5 exposure affected dementia risk. In addition, the investigators were not able to identify a threshold above which dementia risk begins to rise.

The Environmental Pollution Agency considers average yearly exposures up to 12 mcg/m³ to be safe. The World Health Organization sets that limit lower, at 5 mcg/m³.

Dr. Martin noted that more studies are needed to explore those issues, as well as the mechanisms by which air pollutants contribute to the pathology of dementia. However, the clear link between fine particulate matter exposure and increased risk emphasizes the need to address air pollution as a modifiable risk factor for dementia.

“The rising tide of dementia is not something we can easily reverse,” Dr. Martin said. “The evidence has been so elusive for how to treat dementia once you have it, so our biggest opportunity is to prevent it.”

Results from a study published earlier in 2022 estimated that rates of dementia will triple worldwide and double in the United States by 2050 unless steps are taking to mitigate risk factors.

Research also suggests that improving air quality PM_2.5 by just 10% results in a 14% decreased risk for dementia.
 

‘Impressive’ pattern

Paul Rosenberg, MD, codirector of the Memory and Alzheimer’s Treatment Center division of geriatric psychiatry at Johns Hopkins University, Baltimore, said that air pollution “is the most prominent environmental risk we’ve found” for dementia. It also “adds to many other lifestyle and comorbidity risks, such as lack of exercise, obesity, depression, hearing loss, etc,” said Dr. Rosenberg, who was not involved with the research.

He noted what was “most impressive” was that in most of the pooled studies, small particulate air pollution was associated with dementia. “The overall pattern is most impressive and the effect sizes quite consistent over most of the studies,” Dr. Rosenberg said.

The meta-analysis was unfunded. Dr. Martin and Dr. Rosenberg reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Exposure to a traffic-related air pollutant significantly increases risk for dementia, new research suggests. Results from a meta-analysis, which included a total of more than 90 million people, showed risk for dementia increased 3% for every 1 mg/m³ rise in fine particulate matter (PM_2.5) exposure.

Particulate matter is a mixture of solid particles and liquid droplets from the burning of fossil fuels and nitrogen oxide, and also produced from road traffic exhaust.

While the research only showed an association between this type of air pollution and dementia risk, the estimates were consistent across the different analyses used.

“It’s rather sobering that there is this 3% relationship between incidence of dementia and the particulate matter and that it is such a precise estimate,” senior investigator Janet Martin, PharmD, MSc, associate professor of anesthesia & perioperative medicine and epidemiology & biostatistics at Western University’s, London, Ont., told this news organization.

The findings were published online in Neurology.
 

Conflicting results in past studies

Air pollution is a known risk factor for dementia, but studies attempting to pinpoint its exact impact have yielded conflicting results.

Researchers analyzed data from 17 studies with a total of 91.4 million individuals, 6% of whom had dementia. In addition to PM_2.5, the investigators also assessed nitrogen oxides, which form smog, nitrogen dioxide, and ozone exposure.

After adjustments for other known risk factors, such as age and gender, results showed that dementia risk increased by 3% for every 1 m³ rise in PM_2.5 exposure (adjusted hazard ratio, 1.03; 95% confidence interval, 1.02-1.05).

The associations between dementia and exposure to nitrogen oxides (HR, 1.05; 95% CI, 0.99-1.13), nitrogen dioxide (HR, 1.03; 95% CI, 1.00-1.07) and ozone (HR, 1.01; 95% CI, 0.91-1.11) did not reach statistical significance. However, the confidence intervals were wide enough that clinical relevance cannot be ruled out, Dr. Martin said.

The study did not examine how or if the duration of PM_2.5 exposure affected dementia risk. In addition, the investigators were not able to identify a threshold above which dementia risk begins to rise.

The Environmental Pollution Agency considers average yearly exposures up to 12 mcg/m³ to be safe. The World Health Organization sets that limit lower, at 5 mcg/m³.

Dr. Martin noted that more studies are needed to explore those issues, as well as the mechanisms by which air pollutants contribute to the pathology of dementia. However, the clear link between fine particulate matter exposure and increased risk emphasizes the need to address air pollution as a modifiable risk factor for dementia.

“The rising tide of dementia is not something we can easily reverse,” Dr. Martin said. “The evidence has been so elusive for how to treat dementia once you have it, so our biggest opportunity is to prevent it.”

Results from a study published earlier in 2022 estimated that rates of dementia will triple worldwide and double in the United States by 2050 unless steps are taking to mitigate risk factors.

Research also suggests that improving air quality PM_2.5 by just 10% results in a 14% decreased risk for dementia.
 

‘Impressive’ pattern

Paul Rosenberg, MD, codirector of the Memory and Alzheimer’s Treatment Center division of geriatric psychiatry at Johns Hopkins University, Baltimore, said that air pollution “is the most prominent environmental risk we’ve found” for dementia. It also “adds to many other lifestyle and comorbidity risks, such as lack of exercise, obesity, depression, hearing loss, etc,” said Dr. Rosenberg, who was not involved with the research.

He noted what was “most impressive” was that in most of the pooled studies, small particulate air pollution was associated with dementia. “The overall pattern is most impressive and the effect sizes quite consistent over most of the studies,” Dr. Rosenberg said.

The meta-analysis was unfunded. Dr. Martin and Dr. Rosenberg reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.

The incidence of dementia in patients with rheumatoid arthritis who took either a biologic disease-modifying antirheumatic drug (bDMARD) or targeted synthetic DMARD (tsDMARD) was significantly lower than the rate observed in patients who take only a conventional synthetic DMARD (csDMARD) in a national database study.

The work builds on previous research indicating a higher risk of Alzheimer’s disease and related dementias in people with RA. While joint pain and swelling are the cardinal symptoms of RA, its systemic inflammation leads to multiple systemic manifestations, offering biologically plausible links with cognitive decline. In addition, patients with RA have high prevalence of cardiovascular disease, diabetes, depression, disability, and physical inactivity, all of which are risk factors for dementia.

Chronic neuroinflammation secondary to either intrinsic or systemic stimuli is thought to play a key role in dementia development, especially Alzheimer’s dementia (AD). Research showing a role of tumor necrosis factor–alpha (TNF-alpha) in the development of dementia has piqued interest in a potential protective effect of TNF inhibitors. “TNF-alpha is thought to have an important role in different stages of the pathophysiology and disease progression of Alzheimer’s disease,” study first author Sebastian E. Sattui, MD, assistant professor of medicine at the University of Pittsburgh and director of the University of Pittsburgh Vasculitis Center, said in an interview. “Animal models have shown that TNF inhibition reduces microgliosis, neuronal loss, and tau phosphorylation. Cognitive improvement has been seen in two trials with Alzheimer’s disease patients, but were not in rheumatoid arthritis patients.”

In the newest study, published online in Seminars in Arthritis and Rheumatism, Dr. Sattui and colleagues suggest that a lower risk for dementia seen with bDMARDs and tsDMARDs may be attributable to an overall greater decrease in inflammation rather than any mechanism of action specific to these drugs.

In the study of Centers for Medicare & Medicaid Services claims during 2006-2017 for 141,326 adult patients with RA, the crude incident rates were 2.0 per 100 person-years (95% confidence interval, 1.9-2.1) for patients on csDMARDs and 1.3 (95% CI, 1.2-1.4) for patients on any b/tsDMARD. There were 3,794 cases of incident dementia during follow-up among 233,271 initiations of any DMARD. The adjusted risk for dementia among users of bDMARDs or tsDMARDs was 19% lower than the adjusted risk for patients on csDMARDs (hazard ratio, 0.81; 95% CI, 0.76-0.87). No significant differences were found between classes of bDMARDs or tsDMARDs.

Dr. Sattui and coauthors’ investigation included adults aged at least 40 years with two RA diagnoses by a rheumatologist more than 7 and less than 365 days apart. Those with prior dementia diagnoses were excluded. Their analysis found the risk of incident dementia to be comparable between patients receiving TNF inhibitors (HR, 0.86; 95% CI, 0.80-0.93), non-TNFi bDMARDs (HR, 0.76; 95% CI, 0.70-0.83), and tsDMARDs (HR, 0.69; 95% CI, 0.53-0.90), with csDMARDs as the referent. A second subgroup analysis looking at patients with prior methotrexate use who were taking bDMARDs or tsDMARDs revealed similar decreases in risk of incident dementia, compared with patients taking bDMARDs or tsDMARDs along with methotrexate at baseline.

“NSAIDs and glucocorticoids have been studied in RCTs [randomized, controlled trials],” Dr. Sattui said in the interview. “Despite initial observational data that showed some signal for improvement, no benefit was observed in either of the RCTs. Other agents with possible anti-inflammatory effects and more benign profiles, such as curcumin, are being studied. There are also ongoing trials looking into the use of JAK [Janus kinase] inhibitors or [interleukin]-1 inhibition in dementia.”

He added: “There is a need to better study the association between cognition and disease activity, as well as treat-to-target strategies, prospectively in patients with RA. It is important to also acknowledge that any of these findings might be just specific for RA, so extrapolation to non-RA individuals might be limited.”

In commenting on the findings of the study, Rishi J. Desai, PhD, assistant professor of medicine in the division of pharmacoepidemiology and pharmacoeconomics at Brigham and Women’s Hospital, Boston, said that “superior inflammation control with biologics or targeted DMARDs is an interesting hypothesis explaining the observed findings. It merits further investigation and replication in diverse populations.” He added: “It should be noted that a key challenge in evaluating this hypothesis using insurance claims data is unavailability of some important factors such as socioeconomic status and patient frailty. These may be driving treatment selection between conventional DMARDs, which are cheaper with more benign adverse-event profiles, and biologic or targeted DMARDs, which are more expensive with a less favorable adverse-event profile.”
 

Prior research

Several studies have investigated the effect of DMARDs, including bDMARDs like tumor necrosis factor inhibitors, on incident dementia in patients with RA.

Among this research is a study by Dr. Desai and colleagues that looked at comparative risk of AD and related dementia in 22,569 Medicare beneficiaries receiving tofacitinib (a JAK inhibitor), tocilizumab (an IL-6 inhibitor), or TNF inhibitors in comparison with abatacept (a T-cell activation inhibitor). No differentiating risk associations were found in this cohort study.

Other past studies include:

• A study comparing about 21,000 patients with RA and a non-RA cohort of about 62,000 found a 37% reduction in dementia development among RA patients receiving DMARDs. The effect was dose dependent, greater with high cumulative dosages, and was found in both men and women and in subgroups younger and older than 65 years.
• A retrospective study of electronic health records from 56 million adult patients identified a subset of patients with RA, psoriasis, ankylosing spondylitis, ulcerative colitis, or Crohn’s disease in whom systemic inflammation increased risk for AD through a mechanism involving TNF. The risk for AD in patients was lowered by treatment with etanercept, adalimumab, infliximab, or methotrexate, with larger reductions observed in younger patients than in older patients receiving TNF blockers.
• A propensity score–matched retrospective cohort study in 2,510 U.S. veterans with RA found that use of a TNF inhibitor reduced the risk of dementia by 36%, compared with control patients (HR, 0.64; 95% CI, 0.52-0.80), and the effect was consistent over 5-20 years post RA diagnosis.
• In a retrospective, multinational, matched, case-control study of patients older than 50 years with RA, prior methotrexate use was associated with lower dementia risk (OR, 0.71; 95% CI, 0.52-0.98). Use of methotrexate longer than 4 years demonstrated the lowest dementia risk (odds ratio, 0.37; 95% CI, 0.17-0.79).

These past studies, Dr. Sattui and colleagues pointed out, have multiple shortcomings, including case-control design, different definitions of exposure or outcomes, and inadequate control of confounders, underscoring the need for more rigorous studies.

Several authors of the CMS claims study disclosed research support, grants, and consulting fees from pharmaceutical companies. The research was supported by a grant from the National Institutes of Health. Dr. Desai disclosed that he has received funding from the National Institute on Aging for drug repurposing studies of dementia.

The incidence of dementia in patients with rheumatoid arthritis who took either a biologic disease-modifying antirheumatic drug (bDMARD) or targeted synthetic DMARD (tsDMARD) was significantly lower than the rate observed in patients who take only a conventional synthetic DMARD (csDMARD) in a national database study.

The work builds on previous research indicating a higher risk of Alzheimer’s disease and related dementias in people with RA. While joint pain and swelling are the cardinal symptoms of RA, its systemic inflammation leads to multiple systemic manifestations, offering biologically plausible links with cognitive decline. In addition, patients with RA have high prevalence of cardiovascular disease, diabetes, depression, disability, and physical inactivity, all of which are risk factors for dementia.

Chronic neuroinflammation secondary to either intrinsic or systemic stimuli is thought to play a key role in dementia development, especially Alzheimer’s dementia (AD). Research showing a role of tumor necrosis factor–alpha (TNF-alpha) in the development of dementia has piqued interest in a potential protective effect of TNF inhibitors. “TNF-alpha is thought to have an important role in different stages of the pathophysiology and disease progression of Alzheimer’s disease,” study first author Sebastian E. Sattui, MD, assistant professor of medicine at the University of Pittsburgh and director of the University of Pittsburgh Vasculitis Center, said in an interview. “Animal models have shown that TNF inhibition reduces microgliosis, neuronal loss, and tau phosphorylation. Cognitive improvement has been seen in two trials with Alzheimer’s disease patients, but were not in rheumatoid arthritis patients.”

In the newest study, published online in Seminars in Arthritis and Rheumatism, Dr. Sattui and colleagues suggest that a lower risk for dementia seen with bDMARDs and tsDMARDs may be attributable to an overall greater decrease in inflammation rather than any mechanism of action specific to these drugs.

In the study of Centers for Medicare & Medicaid Services claims during 2006-2017 for 141,326 adult patients with RA, the crude incident rates were 2.0 per 100 person-years (95% confidence interval, 1.9-2.1) for patients on csDMARDs and 1.3 (95% CI, 1.2-1.4) for patients on any b/tsDMARD. There were 3,794 cases of incident dementia during follow-up among 233,271 initiations of any DMARD. The adjusted risk for dementia among users of bDMARDs or tsDMARDs was 19% lower than the adjusted risk for patients on csDMARDs (hazard ratio, 0.81; 95% CI, 0.76-0.87). No significant differences were found between classes of bDMARDs or tsDMARDs.

Dr. Sattui and coauthors’ investigation included adults aged at least 40 years with two RA diagnoses by a rheumatologist more than 7 and less than 365 days apart. Those with prior dementia diagnoses were excluded. Their analysis found the risk of incident dementia to be comparable between patients receiving TNF inhibitors (HR, 0.86; 95% CI, 0.80-0.93), non-TNFi bDMARDs (HR, 0.76; 95% CI, 0.70-0.83), and tsDMARDs (HR, 0.69; 95% CI, 0.53-0.90), with csDMARDs as the referent. A second subgroup analysis looking at patients with prior methotrexate use who were taking bDMARDs or tsDMARDs revealed similar decreases in risk of incident dementia, compared with patients taking bDMARDs or tsDMARDs along with methotrexate at baseline.

“NSAIDs and glucocorticoids have been studied in RCTs [randomized, controlled trials],” Dr. Sattui said in the interview. “Despite initial observational data that showed some signal for improvement, no benefit was observed in either of the RCTs. Other agents with possible anti-inflammatory effects and more benign profiles, such as curcumin, are being studied. There are also ongoing trials looking into the use of JAK [Janus kinase] inhibitors or [interleukin]-1 inhibition in dementia.”

He added: “There is a need to better study the association between cognition and disease activity, as well as treat-to-target strategies, prospectively in patients with RA. It is important to also acknowledge that any of these findings might be just specific for RA, so extrapolation to non-RA individuals might be limited.”

In commenting on the findings of the study, Rishi J. Desai, PhD, assistant professor of medicine in the division of pharmacoepidemiology and pharmacoeconomics at Brigham and Women’s Hospital, Boston, said that “superior inflammation control with biologics or targeted DMARDs is an interesting hypothesis explaining the observed findings. It merits further investigation and replication in diverse populations.” He added: “It should be noted that a key challenge in evaluating this hypothesis using insurance claims data is unavailability of some important factors such as socioeconomic status and patient frailty. These may be driving treatment selection between conventional DMARDs, which are cheaper with more benign adverse-event profiles, and biologic or targeted DMARDs, which are more expensive with a less favorable adverse-event profile.”
 

Prior research

Several studies have investigated the effect of DMARDs, including bDMARDs like tumor necrosis factor inhibitors, on incident dementia in patients with RA.

Among this research is a study by Dr. Desai and colleagues that looked at comparative risk of AD and related dementia in 22,569 Medicare beneficiaries receiving tofacitinib (a JAK inhibitor), tocilizumab (an IL-6 inhibitor), or TNF inhibitors in comparison with abatacept (a T-cell activation inhibitor). No differentiating risk associations were found in this cohort study.

Other past studies include:

• A study comparing about 21,000 patients with RA and a non-RA cohort of about 62,000 found a 37% reduction in dementia development among RA patients receiving DMARDs. The effect was dose dependent, greater with high cumulative dosages, and was found in both men and women and in subgroups younger and older than 65 years.
• A retrospective study of electronic health records from 56 million adult patients identified a subset of patients with RA, psoriasis, ankylosing spondylitis, ulcerative colitis, or Crohn’s disease in whom systemic inflammation increased risk for AD through a mechanism involving TNF. The risk for AD in patients was lowered by treatment with etanercept, adalimumab, infliximab, or methotrexate, with larger reductions observed in younger patients than in older patients receiving TNF blockers.
• A propensity score–matched retrospective cohort study in 2,510 U.S. veterans with RA found that use of a TNF inhibitor reduced the risk of dementia by 36%, compared with control patients (HR, 0.64; 95% CI, 0.52-0.80), and the effect was consistent over 5-20 years post RA diagnosis.
• In a retrospective, multinational, matched, case-control study of patients older than 50 years with RA, prior methotrexate use was associated with lower dementia risk (OR, 0.71; 95% CI, 0.52-0.98). Use of methotrexate longer than 4 years demonstrated the lowest dementia risk (odds ratio, 0.37; 95% CI, 0.17-0.79).

These past studies, Dr. Sattui and colleagues pointed out, have multiple shortcomings, including case-control design, different definitions of exposure or outcomes, and inadequate control of confounders, underscoring the need for more rigorous studies.

Several authors of the CMS claims study disclosed research support, grants, and consulting fees from pharmaceutical companies. The research was supported by a grant from the National Institutes of Health. Dr. Desai disclosed that he has received funding from the National Institute on Aging for drug repurposing studies of dementia.

The incidence of dementia in patients with rheumatoid arthritis who took either a biologic disease-modifying antirheumatic drug (bDMARD) or targeted synthetic DMARD (tsDMARD) was significantly lower than the rate observed in patients who take only a conventional synthetic DMARD (csDMARD) in a national database study.

The work builds on previous research indicating a higher risk of Alzheimer’s disease and related dementias in people with RA. While joint pain and swelling are the cardinal symptoms of RA, its systemic inflammation leads to multiple systemic manifestations, offering biologically plausible links with cognitive decline. In addition, patients with RA have high prevalence of cardiovascular disease, diabetes, depression, disability, and physical inactivity, all of which are risk factors for dementia.

Chronic neuroinflammation secondary to either intrinsic or systemic stimuli is thought to play a key role in dementia development, especially Alzheimer’s dementia (AD). Research showing a role of tumor necrosis factor–alpha (TNF-alpha) in the development of dementia has piqued interest in a potential protective effect of TNF inhibitors. “TNF-alpha is thought to have an important role in different stages of the pathophysiology and disease progression of Alzheimer’s disease,” study first author Sebastian E. Sattui, MD, assistant professor of medicine at the University of Pittsburgh and director of the University of Pittsburgh Vasculitis Center, said in an interview. “Animal models have shown that TNF inhibition reduces microgliosis, neuronal loss, and tau phosphorylation. Cognitive improvement has been seen in two trials with Alzheimer’s disease patients, but were not in rheumatoid arthritis patients.”

In the newest study, published online in Seminars in Arthritis and Rheumatism, Dr. Sattui and colleagues suggest that a lower risk for dementia seen with bDMARDs and tsDMARDs may be attributable to an overall greater decrease in inflammation rather than any mechanism of action specific to these drugs.

In the study of Centers for Medicare & Medicaid Services claims during 2006-2017 for 141,326 adult patients with RA, the crude incident rates were 2.0 per 100 person-years (95% confidence interval, 1.9-2.1) for patients on csDMARDs and 1.3 (95% CI, 1.2-1.4) for patients on any b/tsDMARD. There were 3,794 cases of incident dementia during follow-up among 233,271 initiations of any DMARD. The adjusted risk for dementia among users of bDMARDs or tsDMARDs was 19% lower than the adjusted risk for patients on csDMARDs (hazard ratio, 0.81; 95% CI, 0.76-0.87). No significant differences were found between classes of bDMARDs or tsDMARDs.

Dr. Sattui and coauthors’ investigation included adults aged at least 40 years with two RA diagnoses by a rheumatologist more than 7 and less than 365 days apart. Those with prior dementia diagnoses were excluded. Their analysis found the risk of incident dementia to be comparable between patients receiving TNF inhibitors (HR, 0.86; 95% CI, 0.80-0.93), non-TNFi bDMARDs (HR, 0.76; 95% CI, 0.70-0.83), and tsDMARDs (HR, 0.69; 95% CI, 0.53-0.90), with csDMARDs as the referent. A second subgroup analysis looking at patients with prior methotrexate use who were taking bDMARDs or tsDMARDs revealed similar decreases in risk of incident dementia, compared with patients taking bDMARDs or tsDMARDs along with methotrexate at baseline.

“NSAIDs and glucocorticoids have been studied in RCTs [randomized, controlled trials],” Dr. Sattui said in the interview. “Despite initial observational data that showed some signal for improvement, no benefit was observed in either of the RCTs. Other agents with possible anti-inflammatory effects and more benign profiles, such as curcumin, are being studied. There are also ongoing trials looking into the use of JAK [Janus kinase] inhibitors or [interleukin]-1 inhibition in dementia.”

He added: “There is a need to better study the association between cognition and disease activity, as well as treat-to-target strategies, prospectively in patients with RA. It is important to also acknowledge that any of these findings might be just specific for RA, so extrapolation to non-RA individuals might be limited.”

In commenting on the findings of the study, Rishi J. Desai, PhD, assistant professor of medicine in the division of pharmacoepidemiology and pharmacoeconomics at Brigham and Women’s Hospital, Boston, said that “superior inflammation control with biologics or targeted DMARDs is an interesting hypothesis explaining the observed findings. It merits further investigation and replication in diverse populations.” He added: “It should be noted that a key challenge in evaluating this hypothesis using insurance claims data is unavailability of some important factors such as socioeconomic status and patient frailty. These may be driving treatment selection between conventional DMARDs, which are cheaper with more benign adverse-event profiles, and biologic or targeted DMARDs, which are more expensive with a less favorable adverse-event profile.”
 

Prior research

Several studies have investigated the effect of DMARDs, including bDMARDs like tumor necrosis factor inhibitors, on incident dementia in patients with RA.

Among this research is a study by Dr. Desai and colleagues that looked at comparative risk of AD and related dementia in 22,569 Medicare beneficiaries receiving tofacitinib (a JAK inhibitor), tocilizumab (an IL-6 inhibitor), or TNF inhibitors in comparison with abatacept (a T-cell activation inhibitor). No differentiating risk associations were found in this cohort study.

Other past studies include:

• A study comparing about 21,000 patients with RA and a non-RA cohort of about 62,000 found a 37% reduction in dementia development among RA patients receiving DMARDs. The effect was dose dependent, greater with high cumulative dosages, and was found in both men and women and in subgroups younger and older than 65 years.
• A retrospective study of electronic health records from 56 million adult patients identified a subset of patients with RA, psoriasis, ankylosing spondylitis, ulcerative colitis, or Crohn’s disease in whom systemic inflammation increased risk for AD through a mechanism involving TNF. The risk for AD in patients was lowered by treatment with etanercept, adalimumab, infliximab, or methotrexate, with larger reductions observed in younger patients than in older patients receiving TNF blockers.
• A propensity score–matched retrospective cohort study in 2,510 U.S. veterans with RA found that use of a TNF inhibitor reduced the risk of dementia by 36%, compared with control patients (HR, 0.64; 95% CI, 0.52-0.80), and the effect was consistent over 5-20 years post RA diagnosis.
• In a retrospective, multinational, matched, case-control study of patients older than 50 years with RA, prior methotrexate use was associated with lower dementia risk (OR, 0.71; 95% CI, 0.52-0.98). Use of methotrexate longer than 4 years demonstrated the lowest dementia risk (odds ratio, 0.37; 95% CI, 0.17-0.79).

These past studies, Dr. Sattui and colleagues pointed out, have multiple shortcomings, including case-control design, different definitions of exposure or outcomes, and inadequate control of confounders, underscoring the need for more rigorous studies.

Several authors of the CMS claims study disclosed research support, grants, and consulting fees from pharmaceutical companies. The research was supported by a grant from the National Institutes of Health. Dr. Desai disclosed that he has received funding from the National Institute on Aging for drug repurposing studies of dementia.

Researchers have identified a set of 42 genes that are associated with dyslexia, based on data from approximately 50,000 dyslexic individuals and 1 million controls.

Dyslexia occurs in 5%-17% of the general population, depending on the diagnostic criteria, and has been linked with speech and language disorders, as well as ADHD, Catherine Doust, PhD, of the University of Edinburgh and colleagues wrote.

However, previous studies of the genetics of dyslexia are limited, corresponding author Michelle Luciano, PhD, said in an interview. “So much progress has been made in understanding the genetics of behavior and health, but only a small genomewide study of dyslexia existed before ours.”

Currently, genetic testing for dyslexia alone is not done.

“You couldn’t order a genetic test for dyslexia unless it were part of another genetic panel,” according to Herschel Lessin, MD, of Children’s Medical Group, Poughkeepsie, N.Y.

There are also known associations with some genes and autism, but none are definitive, and testing requires a workup of which a genetic panel may be a part. Such tests are expensive, and rarely covered by insurance, the pediatrician explained. 

Experts recommend genetic screening for every child with developmental delay, but most insurance won’t cover it, Dr. Lessin continued.

In the new genomewide association study published in Nature Genetics, the researchers reviewed data from 51,800 adults aged 18 years and older with a self-reported dyslexia diagnosis and 1,087,070 controls. All study participants are enrolled in ongoing research with 23andMe, the personal genetics company.

The researchers investigated the genetic correlations with reading and related skills and evaluated evidence for genes previously associated with dyslexia. The mean ages of the dyslexia cases and controls were 49.6 years and 51.7 years, respectively.

The researchers identified 42 independent genetic variants (genomewide significant loci) associated with dyslexia; 15 of these loci were in genes previously associated with cognitive ability and educational attainment, and 27 were newly identified as specifically associated with dyslexia. The researchers further determined that 12 of the newly identified genes were associated with proficiency in reading and spelling in English and European languages, and 1 in a Chinese-language population.

A polygenic risk score is a way to characterize an individual’s risk of developing a disease, based on the total number of genetic changes related to the disease; the researchers used this score to validate their results. Dyslexia polygenic scores were used to predict reading and spelling in additional population-based and reading disorder–enriched samples outside of the study population; these genetic measures explained up to 6% of variance in reading traits, the researchers noted. Ultimately, these scores may be a tool to help identify children with a predisposition for dyslexia so reading skills support can begin early.

The researchers also found that many of the genes associated with dyslexia are also associated with ADHD, (24% of dyslexia patients reporting ADHD vs. 9% of controls), and with a moderate correlation, which suggests possible shared genetic components for deficits in working memory and attention.

The study findings were limited by the inability to prove causality, and by the potential bias in the study sample, but were strengthened by the large study population, the researchers noted.
 

Potential implications for reading and spelling

“We were surprised that none of the previous dyslexia candidate genes were genomewide significant in our study; all of our discoveries were in new genes that had not been previously implicated in dyslexia,” Dr. Luciano said in an interview. “Some of these genes have been found to be associated with general cognitive ability, but most were novel and may represent genes specifically related to cognitive processes dominant in reading and spelling.

“We were also surprised that there was little genetic correlation (or overlap) with brain MRI variables, given that brain regions have been linked to reading skill. This suggests that the link is environmental in origin,” she added.

“Our results do not directly feed into clinical practice,” said Dr. Luciano. However, “the moderate genetic overlap with ADHD suggests that broader assessments of behavior are important when a child presents with dyslexia, as co-occurrence with other conditions might influence the intervention chosen. Asking about family history of dyslexia might also help in identification.

With more research, genetic studies may find a place in the clinical setting, said Dr. Luciano.  

“As genomewide association studies become larger and the findings more stable, genetic information might be used as an adjunct to what is known about the child’s environment and their performance on standardized tests of reading. The key advantage of genetic information is that it could allow much earlier identification of children who would benefit from extra learning support,” she said.

More research is needed to understand the interaction between genes and the environment, Dr. Luciano said. “It is essential that we understand what environmental learning support can minimize genetic predisposition to dyslexia.”
 

Too soon for clinical utility

The study findings are an important foundation for additional research, but not yet clinically useful, Dr. Lessin said in an interview.

“Dyslexia is a tough diagnosis,” that requires assessment by a developmental pediatrician or a pediatric neurologist and these specialists are often not accessible to many parents, Dr. Lessin noted.

In the current study, the researchers found a number of genes potentially associated with dyslexia, but the study does not prove causality, he emphasized. The findings simply mean that some of these genes may have something to do with dyslexia, and further research might identify a genetic cause.

“No one is going to make a diagnosis of dyslexia based on genes just yet,” said Dr. Lessin. In the meantime, clinicians should be aware that good research is being conducted, and that the genetic foundations for dyslexia are being explored.

Lead author Dr. Doust and corresponding author Dr. Luciano had no financial conflicts to disclose. Several coauthors disclosed support from the Max Planck Society (Germany), the National Natural Science Foundation of China, Funds for Humanities and Social Sciences Research of the Ministry of Education, and General Project of Shaanxi Natural Science Basic Research Program. Two coauthors are employed by and hold stock or stock options in 23andMe. Dr. Lessin had no financial conflicts to disclose, but serves on the editorial advisory board of Pediatric News.

Researchers have identified a set of 42 genes that are associated with dyslexia, based on data from approximately 50,000 dyslexic individuals and 1 million controls.

Dyslexia occurs in 5%-17% of the general population, depending on the diagnostic criteria, and has been linked with speech and language disorders, as well as ADHD, Catherine Doust, PhD, of the University of Edinburgh and colleagues wrote.

However, previous studies of the genetics of dyslexia are limited, corresponding author Michelle Luciano, PhD, said in an interview. “So much progress has been made in understanding the genetics of behavior and health, but only a small genomewide study of dyslexia existed before ours.”

Currently, genetic testing for dyslexia alone is not done.

“You couldn’t order a genetic test for dyslexia unless it were part of another genetic panel,” according to Herschel Lessin, MD, of Children’s Medical Group, Poughkeepsie, N.Y.

There are also known associations with some genes and autism, but none are definitive, and testing requires a workup of which a genetic panel may be a part. Such tests are expensive, and rarely covered by insurance, the pediatrician explained. 

Experts recommend genetic screening for every child with developmental delay, but most insurance won’t cover it, Dr. Lessin continued.

In the new genomewide association study published in Nature Genetics, the researchers reviewed data from 51,800 adults aged 18 years and older with a self-reported dyslexia diagnosis and 1,087,070 controls. All study participants are enrolled in ongoing research with 23andMe, the personal genetics company.

The researchers investigated the genetic correlations with reading and related skills and evaluated evidence for genes previously associated with dyslexia. The mean ages of the dyslexia cases and controls were 49.6 years and 51.7 years, respectively.

The researchers identified 42 independent genetic variants (genomewide significant loci) associated with dyslexia; 15 of these loci were in genes previously associated with cognitive ability and educational attainment, and 27 were newly identified as specifically associated with dyslexia. The researchers further determined that 12 of the newly identified genes were associated with proficiency in reading and spelling in English and European languages, and 1 in a Chinese-language population.

A polygenic risk score is a way to characterize an individual’s risk of developing a disease, based on the total number of genetic changes related to the disease; the researchers used this score to validate their results. Dyslexia polygenic scores were used to predict reading and spelling in additional population-based and reading disorder–enriched samples outside of the study population; these genetic measures explained up to 6% of variance in reading traits, the researchers noted. Ultimately, these scores may be a tool to help identify children with a predisposition for dyslexia so reading skills support can begin early.

The researchers also found that many of the genes associated with dyslexia are also associated with ADHD, (24% of dyslexia patients reporting ADHD vs. 9% of controls), and with a moderate correlation, which suggests possible shared genetic components for deficits in working memory and attention.

The study findings were limited by the inability to prove causality, and by the potential bias in the study sample, but were strengthened by the large study population, the researchers noted.
 

Potential implications for reading and spelling

“We were surprised that none of the previous dyslexia candidate genes were genomewide significant in our study; all of our discoveries were in new genes that had not been previously implicated in dyslexia,” Dr. Luciano said in an interview. “Some of these genes have been found to be associated with general cognitive ability, but most were novel and may represent genes specifically related to cognitive processes dominant in reading and spelling.

“We were also surprised that there was little genetic correlation (or overlap) with brain MRI variables, given that brain regions have been linked to reading skill. This suggests that the link is environmental in origin,” she added.

“Our results do not directly feed into clinical practice,” said Dr. Luciano. However, “the moderate genetic overlap with ADHD suggests that broader assessments of behavior are important when a child presents with dyslexia, as co-occurrence with other conditions might influence the intervention chosen. Asking about family history of dyslexia might also help in identification.

With more research, genetic studies may find a place in the clinical setting, said Dr. Luciano.  

“As genomewide association studies become larger and the findings more stable, genetic information might be used as an adjunct to what is known about the child’s environment and their performance on standardized tests of reading. The key advantage of genetic information is that it could allow much earlier identification of children who would benefit from extra learning support,” she said.

More research is needed to understand the interaction between genes and the environment, Dr. Luciano said. “It is essential that we understand what environmental learning support can minimize genetic predisposition to dyslexia.”
 

Too soon for clinical utility

The study findings are an important foundation for additional research, but not yet clinically useful, Dr. Lessin said in an interview.

“Dyslexia is a tough diagnosis,” that requires assessment by a developmental pediatrician or a pediatric neurologist and these specialists are often not accessible to many parents, Dr. Lessin noted.

In the current study, the researchers found a number of genes potentially associated with dyslexia, but the study does not prove causality, he emphasized. The findings simply mean that some of these genes may have something to do with dyslexia, and further research might identify a genetic cause.

“No one is going to make a diagnosis of dyslexia based on genes just yet,” said Dr. Lessin. In the meantime, clinicians should be aware that good research is being conducted, and that the genetic foundations for dyslexia are being explored.

Lead author Dr. Doust and corresponding author Dr. Luciano had no financial conflicts to disclose. Several coauthors disclosed support from the Max Planck Society (Germany), the National Natural Science Foundation of China, Funds for Humanities and Social Sciences Research of the Ministry of Education, and General Project of Shaanxi Natural Science Basic Research Program. Two coauthors are employed by and hold stock or stock options in 23andMe. Dr. Lessin had no financial conflicts to disclose, but serves on the editorial advisory board of Pediatric News.

Researchers have identified a set of 42 genes that are associated with dyslexia, based on data from approximately 50,000 dyslexic individuals and 1 million controls.

Dyslexia occurs in 5%-17% of the general population, depending on the diagnostic criteria, and has been linked with speech and language disorders, as well as ADHD, Catherine Doust, PhD, of the University of Edinburgh and colleagues wrote.

However, previous studies of the genetics of dyslexia are limited, corresponding author Michelle Luciano, PhD, said in an interview. “So much progress has been made in understanding the genetics of behavior and health, but only a small genomewide study of dyslexia existed before ours.”

Currently, genetic testing for dyslexia alone is not done.

“You couldn’t order a genetic test for dyslexia unless it were part of another genetic panel,” according to Herschel Lessin, MD, of Children’s Medical Group, Poughkeepsie, N.Y.

There are also known associations with some genes and autism, but none are definitive, and testing requires a workup of which a genetic panel may be a part. Such tests are expensive, and rarely covered by insurance, the pediatrician explained. 

Experts recommend genetic screening for every child with developmental delay, but most insurance won’t cover it, Dr. Lessin continued.

In the new genomewide association study published in Nature Genetics, the researchers reviewed data from 51,800 adults aged 18 years and older with a self-reported dyslexia diagnosis and 1,087,070 controls. All study participants are enrolled in ongoing research with 23andMe, the personal genetics company.

The researchers investigated the genetic correlations with reading and related skills and evaluated evidence for genes previously associated with dyslexia. The mean ages of the dyslexia cases and controls were 49.6 years and 51.7 years, respectively.

The researchers identified 42 independent genetic variants (genomewide significant loci) associated with dyslexia; 15 of these loci were in genes previously associated with cognitive ability and educational attainment, and 27 were newly identified as specifically associated with dyslexia. The researchers further determined that 12 of the newly identified genes were associated with proficiency in reading and spelling in English and European languages, and 1 in a Chinese-language population.

A polygenic risk score is a way to characterize an individual’s risk of developing a disease, based on the total number of genetic changes related to the disease; the researchers used this score to validate their results. Dyslexia polygenic scores were used to predict reading and spelling in additional population-based and reading disorder–enriched samples outside of the study population; these genetic measures explained up to 6% of variance in reading traits, the researchers noted. Ultimately, these scores may be a tool to help identify children with a predisposition for dyslexia so reading skills support can begin early.

The researchers also found that many of the genes associated with dyslexia are also associated with ADHD, (24% of dyslexia patients reporting ADHD vs. 9% of controls), and with a moderate correlation, which suggests possible shared genetic components for deficits in working memory and attention.

The study findings were limited by the inability to prove causality, and by the potential bias in the study sample, but were strengthened by the large study population, the researchers noted.
 

Potential implications for reading and spelling

“We were surprised that none of the previous dyslexia candidate genes were genomewide significant in our study; all of our discoveries were in new genes that had not been previously implicated in dyslexia,” Dr. Luciano said in an interview. “Some of these genes have been found to be associated with general cognitive ability, but most were novel and may represent genes specifically related to cognitive processes dominant in reading and spelling.

“We were also surprised that there was little genetic correlation (or overlap) with brain MRI variables, given that brain regions have been linked to reading skill. This suggests that the link is environmental in origin,” she added.

“Our results do not directly feed into clinical practice,” said Dr. Luciano. However, “the moderate genetic overlap with ADHD suggests that broader assessments of behavior are important when a child presents with dyslexia, as co-occurrence with other conditions might influence the intervention chosen. Asking about family history of dyslexia might also help in identification.

With more research, genetic studies may find a place in the clinical setting, said Dr. Luciano.  

“As genomewide association studies become larger and the findings more stable, genetic information might be used as an adjunct to what is known about the child’s environment and their performance on standardized tests of reading. The key advantage of genetic information is that it could allow much earlier identification of children who would benefit from extra learning support,” she said.

More research is needed to understand the interaction between genes and the environment, Dr. Luciano said. “It is essential that we understand what environmental learning support can minimize genetic predisposition to dyslexia.”
 

Too soon for clinical utility

The study findings are an important foundation for additional research, but not yet clinically useful, Dr. Lessin said in an interview.

“Dyslexia is a tough diagnosis,” that requires assessment by a developmental pediatrician or a pediatric neurologist and these specialists are often not accessible to many parents, Dr. Lessin noted.

In the current study, the researchers found a number of genes potentially associated with dyslexia, but the study does not prove causality, he emphasized. The findings simply mean that some of these genes may have something to do with dyslexia, and further research might identify a genetic cause.

“No one is going to make a diagnosis of dyslexia based on genes just yet,” said Dr. Lessin. In the meantime, clinicians should be aware that good research is being conducted, and that the genetic foundations for dyslexia are being explored.

Lead author Dr. Doust and corresponding author Dr. Luciano had no financial conflicts to disclose. Several coauthors disclosed support from the Max Planck Society (Germany), the National Natural Science Foundation of China, Funds for Humanities and Social Sciences Research of the Ministry of Education, and General Project of Shaanxi Natural Science Basic Research Program. Two coauthors are employed by and hold stock or stock options in 23andMe. Dr. Lessin had no financial conflicts to disclose, but serves on the editorial advisory board of Pediatric News.

Dementia and mild cognitive impairment (MCI) disproportionately affect Black and Hispanic individuals, as well as people with less education, based on new U.S. data from The Health and Retirement Study (HRS).

These inequities likely stem from structural racism and income inequality, necessitating a multifaceted response at an institutional level, according to lead author Jennifer J. Manly, PhD, a professor of neuropsychology in neurology at the Gertrude H. Sergievsky Center and the Taub Institute for Research in Aging and Alzheimer’s Disease at Columbia University, New York.
 

A more representative dataset

Between 2001 and 2003, a subset of HRS participants underwent extensive neuropsychological assessment in the Aging, Demographics, and Memory Study (ADAMS), providing data which have since been cited by hundreds of published studies, the investigators wrote in JAMA Neurology. Those data, however, failed to accurately represent the U.S. population at the time, and have not been updated since.

“The ADAMS substudy was small, and the limited inclusion of Black, Hispanic, and American Indian or Alaska Native participants contributed to lack of precision of estimates among minoritized racial and ethnic groups that have been shown to experience a higher burden of cognitive impairment and dementia,” Dr. Manly and colleagues wrote.

The present analysis used a more representative dataset from HRS participants who were 65 years or older in 2016. From June 2016 to October 2017, 3,496 of these individuals underwent comprehensive neuropsychological test battery and informant interview, with dementia and MCI classified based on standard diagnostic criteria.

In total, 393 people were classified with dementia (10%), while 804 had MCI (22%), both of which approximate estimates reported by previous studies, according to the investigators. In further alignment with past research, age was a clear risk factor; each 5-year increment added 17% and 95% increased risk of MCI and dementia, respectively.

Compared with college-educated participants, individuals who did not graduate from high school had a 60% increased risk for both dementia (odds ratio, 1.6; 95% confidence interval, 1.1-2.3) and MCI (OR, 1.6; 95% CI, 1.2-2.2). Other educational strata were not associated with significant differences in risk.

Compared with White participants, Black individuals had an 80% increased risk of dementia (OR, 1.8; 95% CI, 1.2-2.7), but no increased risk of MCI. Conversely, non-White Hispanic individuals had a 40% increased risk of MCI (OR, 1.4; 95% CI, 1.0-2.0), but no increased risk of dementia, compared with White participants.

“Older adults racialized as Black and Hispanic are more likely to develop cognitive impairment and dementia because of historical and current structural racism and income inequality that restrict access to brain-health benefits and increase exposure to harm,” Dr. Manly said in a written comment.

These inequities deserve a comprehensive response, she added.

“Actions and policies that decrease discriminatory and aggressive policing policies, invest in schools that serve children that are racialized as Black and Hispanic, repair housing and economic inequalities, and provide equitable access to mental and physical health, can help to narrow disparities in later life cognitive impairment,” Dr. Manly said. “Two other areas of focus for policy makers are the shortage in the workforce of dementia care specialists, and paid family leave for caregiving.”
 

Acknowledging the needs of the historically underrepresented

Lealani Mae Acosta, MD, MPH, associate professor of neurology at Vanderbilt University Medical Center, Nashville, Tenn., applauded the investigators for their “conscious effort to expand representation of historically underrepresented minorities.”

The findings themselves support what has been previously reported, Dr. Acosta said in an interview, including the disproportionate burden of cognitive disorders among people of color and those with less education.

Clinicians need to recognize that certain patient groups face increased risks of cognitive disorders, and should be screened accordingly, Dr. Acosta said, noting that all aging patients should undergo such screening. The push for screening should also occur on a community level, along with efforts to build trust between at-risk populations and health care providers.

While Dr. Acosta reiterated the importance of these new data from Black and Hispanic individuals, she noted that gaps in representation remain, and methods of characterizing populations deserve refinement.

“I’m a little bit biased because I’m an Asian physician,” Dr. Acosta said. “As much as I’m glad that they’re highlighting these different disparities, there weren’t enough [participants in] specific subgroups like American Indian or Alaska Native, Asian, Native Hawaiian or Pacific Islander, to be able to identify specific trends within [those groups] that are, again, historically underrepresented patient populations.”

Grouping all people of Asian descent may also be an oversimplification, she added, as differences may exist between individuals originating from different countries.

“We always have to be careful about lumping certain groups together in analyses,” Dr. Acosta said. “That’s just another reminder to us – as clinicians, as researchers – that we need to do better by our patients by expanding research opportunities, and really studying these historically underrepresented populations.”

The study was supported by the National Institute on Aging. The investigators disclosed additional relationships with the Alzheimer’s Association and the National Institutes of Health. Dr. Acosta reported no relevant competing interests.

Dementia and mild cognitive impairment (MCI) disproportionately affect Black and Hispanic individuals, as well as people with less education, based on new U.S. data from The Health and Retirement Study (HRS).

These inequities likely stem from structural racism and income inequality, necessitating a multifaceted response at an institutional level, according to lead author Jennifer J. Manly, PhD, a professor of neuropsychology in neurology at the Gertrude H. Sergievsky Center and the Taub Institute for Research in Aging and Alzheimer’s Disease at Columbia University, New York.
 

A more representative dataset

Between 2001 and 2003, a subset of HRS participants underwent extensive neuropsychological assessment in the Aging, Demographics, and Memory Study (ADAMS), providing data which have since been cited by hundreds of published studies, the investigators wrote in JAMA Neurology. Those data, however, failed to accurately represent the U.S. population at the time, and have not been updated since.

“The ADAMS substudy was small, and the limited inclusion of Black, Hispanic, and American Indian or Alaska Native participants contributed to lack of precision of estimates among minoritized racial and ethnic groups that have been shown to experience a higher burden of cognitive impairment and dementia,” Dr. Manly and colleagues wrote.

The present analysis used a more representative dataset from HRS participants who were 65 years or older in 2016. From June 2016 to October 2017, 3,496 of these individuals underwent comprehensive neuropsychological test battery and informant interview, with dementia and MCI classified based on standard diagnostic criteria.

In total, 393 people were classified with dementia (10%), while 804 had MCI (22%), both of which approximate estimates reported by previous studies, according to the investigators. In further alignment with past research, age was a clear risk factor; each 5-year increment added 17% and 95% increased risk of MCI and dementia, respectively.

Compared with college-educated participants, individuals who did not graduate from high school had a 60% increased risk for both dementia (odds ratio, 1.6; 95% confidence interval, 1.1-2.3) and MCI (OR, 1.6; 95% CI, 1.2-2.2). Other educational strata were not associated with significant differences in risk.

Compared with White participants, Black individuals had an 80% increased risk of dementia (OR, 1.8; 95% CI, 1.2-2.7), but no increased risk of MCI. Conversely, non-White Hispanic individuals had a 40% increased risk of MCI (OR, 1.4; 95% CI, 1.0-2.0), but no increased risk of dementia, compared with White participants.

“Older adults racialized as Black and Hispanic are more likely to develop cognitive impairment and dementia because of historical and current structural racism and income inequality that restrict access to brain-health benefits and increase exposure to harm,” Dr. Manly said in a written comment.

These inequities deserve a comprehensive response, she added.

“Actions and policies that decrease discriminatory and aggressive policing policies, invest in schools that serve children that are racialized as Black and Hispanic, repair housing and economic inequalities, and provide equitable access to mental and physical health, can help to narrow disparities in later life cognitive impairment,” Dr. Manly said. “Two other areas of focus for policy makers are the shortage in the workforce of dementia care specialists, and paid family leave for caregiving.”
 

Acknowledging the needs of the historically underrepresented

Lealani Mae Acosta, MD, MPH, associate professor of neurology at Vanderbilt University Medical Center, Nashville, Tenn., applauded the investigators for their “conscious effort to expand representation of historically underrepresented minorities.”

The findings themselves support what has been previously reported, Dr. Acosta said in an interview, including the disproportionate burden of cognitive disorders among people of color and those with less education.

Clinicians need to recognize that certain patient groups face increased risks of cognitive disorders, and should be screened accordingly, Dr. Acosta said, noting that all aging patients should undergo such screening. The push for screening should also occur on a community level, along with efforts to build trust between at-risk populations and health care providers.

While Dr. Acosta reiterated the importance of these new data from Black and Hispanic individuals, she noted that gaps in representation remain, and methods of characterizing populations deserve refinement.

“I’m a little bit biased because I’m an Asian physician,” Dr. Acosta said. “As much as I’m glad that they’re highlighting these different disparities, there weren’t enough [participants in] specific subgroups like American Indian or Alaska Native, Asian, Native Hawaiian or Pacific Islander, to be able to identify specific trends within [those groups] that are, again, historically underrepresented patient populations.”

Grouping all people of Asian descent may also be an oversimplification, she added, as differences may exist between individuals originating from different countries.

“We always have to be careful about lumping certain groups together in analyses,” Dr. Acosta said. “That’s just another reminder to us – as clinicians, as researchers – that we need to do better by our patients by expanding research opportunities, and really studying these historically underrepresented populations.”

The study was supported by the National Institute on Aging. The investigators disclosed additional relationships with the Alzheimer’s Association and the National Institutes of Health. Dr. Acosta reported no relevant competing interests.

Dementia and mild cognitive impairment (MCI) disproportionately affect Black and Hispanic individuals, as well as people with less education, based on new U.S. data from The Health and Retirement Study (HRS).

These inequities likely stem from structural racism and income inequality, necessitating a multifaceted response at an institutional level, according to lead author Jennifer J. Manly, PhD, a professor of neuropsychology in neurology at the Gertrude H. Sergievsky Center and the Taub Institute for Research in Aging and Alzheimer’s Disease at Columbia University, New York.
 

A more representative dataset

Between 2001 and 2003, a subset of HRS participants underwent extensive neuropsychological assessment in the Aging, Demographics, and Memory Study (ADAMS), providing data which have since been cited by hundreds of published studies, the investigators wrote in JAMA Neurology. Those data, however, failed to accurately represent the U.S. population at the time, and have not been updated since.

“The ADAMS substudy was small, and the limited inclusion of Black, Hispanic, and American Indian or Alaska Native participants contributed to lack of precision of estimates among minoritized racial and ethnic groups that have been shown to experience a higher burden of cognitive impairment and dementia,” Dr. Manly and colleagues wrote.

The present analysis used a more representative dataset from HRS participants who were 65 years or older in 2016. From June 2016 to October 2017, 3,496 of these individuals underwent comprehensive neuropsychological test battery and informant interview, with dementia and MCI classified based on standard diagnostic criteria.

In total, 393 people were classified with dementia (10%), while 804 had MCI (22%), both of which approximate estimates reported by previous studies, according to the investigators. In further alignment with past research, age was a clear risk factor; each 5-year increment added 17% and 95% increased risk of MCI and dementia, respectively.

Compared with college-educated participants, individuals who did not graduate from high school had a 60% increased risk for both dementia (odds ratio, 1.6; 95% confidence interval, 1.1-2.3) and MCI (OR, 1.6; 95% CI, 1.2-2.2). Other educational strata were not associated with significant differences in risk.

Compared with White participants, Black individuals had an 80% increased risk of dementia (OR, 1.8; 95% CI, 1.2-2.7), but no increased risk of MCI. Conversely, non-White Hispanic individuals had a 40% increased risk of MCI (OR, 1.4; 95% CI, 1.0-2.0), but no increased risk of dementia, compared with White participants.

“Older adults racialized as Black and Hispanic are more likely to develop cognitive impairment and dementia because of historical and current structural racism and income inequality that restrict access to brain-health benefits and increase exposure to harm,” Dr. Manly said in a written comment.

These inequities deserve a comprehensive response, she added.

“Actions and policies that decrease discriminatory and aggressive policing policies, invest in schools that serve children that are racialized as Black and Hispanic, repair housing and economic inequalities, and provide equitable access to mental and physical health, can help to narrow disparities in later life cognitive impairment,” Dr. Manly said. “Two other areas of focus for policy makers are the shortage in the workforce of dementia care specialists, and paid family leave for caregiving.”
 

Acknowledging the needs of the historically underrepresented

Lealani Mae Acosta, MD, MPH, associate professor of neurology at Vanderbilt University Medical Center, Nashville, Tenn., applauded the investigators for their “conscious effort to expand representation of historically underrepresented minorities.”

The findings themselves support what has been previously reported, Dr. Acosta said in an interview, including the disproportionate burden of cognitive disorders among people of color and those with less education.

Clinicians need to recognize that certain patient groups face increased risks of cognitive disorders, and should be screened accordingly, Dr. Acosta said, noting that all aging patients should undergo such screening. The push for screening should also occur on a community level, along with efforts to build trust between at-risk populations and health care providers.

While Dr. Acosta reiterated the importance of these new data from Black and Hispanic individuals, she noted that gaps in representation remain, and methods of characterizing populations deserve refinement.

“I’m a little bit biased because I’m an Asian physician,” Dr. Acosta said. “As much as I’m glad that they’re highlighting these different disparities, there weren’t enough [participants in] specific subgroups like American Indian or Alaska Native, Asian, Native Hawaiian or Pacific Islander, to be able to identify specific trends within [those groups] that are, again, historically underrepresented patient populations.”

Grouping all people of Asian descent may also be an oversimplification, she added, as differences may exist between individuals originating from different countries.

“We always have to be careful about lumping certain groups together in analyses,” Dr. Acosta said. “That’s just another reminder to us – as clinicians, as researchers – that we need to do better by our patients by expanding research opportunities, and really studying these historically underrepresented populations.”

The study was supported by the National Institute on Aging. The investigators disclosed additional relationships with the Alzheimer’s Association and the National Institutes of Health. Dr. Acosta reported no relevant competing interests.

Patients with psychotic disorders such as schizophrenia are more than twice as likely as those without a psychotic disorder to eventually develop dementia, new research suggests.

Results from a review and meta-analysis of almost 13 million total participants from nine countries showed that, across multiple different psychotic disorders, there was a 2.5-fold higher risk of developing dementia later in life compared with individuals who did not have a disorder. This was regardless of the age at which the patients first developed the mental illness.

Moreover, participants with a psychotic disorder tended to be younger than average when diagnosed with dementia. Two studies showed that those with psychotic disorders were more likely to be diagnosed with dementia as early as in their 60s.

“The findings add to a growing body of evidence linking psychiatric disorders with later cognitive decline and dementia,” senior investigator Jean Stafford, PhD, a research fellow at MRC Unit for Lifelong Health and Ageing, University College London, told this news organization.

Dr. Stafford noted that the results highlight the importance of being aware of and watchful for symptoms of cognitive decline in patients with psychotic disorders in mid- and late life.

“In addition, given that people with psychotic disorders are at higher risk of experiencing multiple health conditions, including dementia, managing overall physical and mental health in this group is crucial,” she said.

The findings were published online in Psychological Medicine.
 

Bringing the evidence together

There is increasing evidence that multiple psychiatric symptoms and diagnoses are associated with cognitive decline and dementia, with particularly strong evidence for late-life depression, Dr. Stafford said.

“However, the relationship between psychotic disorders and dementia is less well-established,” she added.

Last year, her team published a study showing a strong association between very late onset psychotic disorders, defined as first diagnosed after age 60 years, and increased risk for dementia in Swedish population register data.

“We also became aware of several other large studies on the topic published in the last few years and realized that an up-to-date systematic review and meta-analysis was needed to bring together the evidence, specifically focusing on longitudinal studies,” Dr. Stafford said.

The researchers searched four databases of prospective and retrospective longitudinal studies published through March 2022. Studies were required to focus on adults aged 18 years or older with a clinical diagnosis of a nonaffective psychotic disorder and a comparison group consisting of adults without a nonaffective psychotic disorder.

Of 9,496 papers, the investigators selected 11 published from 2003 to 2022 that met criteria for inclusion in their meta-analysis (12,997,101 participants), with follow-up periods ranging from 1.57 to 33 years.

The studies hailed from Denmark, Finland, Sweden, the United Kingdom, the United States, Australia, Taiwan, New Zealand, and Israel.

Random-effects meta-analyses were used to pool estimates across studies. The researchers assessed the risk of bias for each study. They also included two additional studies in the review, but not the meta-analysis, that focused specifically on late-onset acute and transient psychosis and late-onset delusional disorder.

The other studies focused on late-onset schizophrenia and/or very late onset schizophrenia-like psychoses, schizophrenia, psychotic disorders, and schizophrenia in older people.

Most studies investigated the incidence of all-cause dementia, although one study focused on the incidence of Alzheimer’s disease.
 

Potential mechanisms

The narrative review showed that most studies (n = 10) were of high methodological quality, although two were rated as fair and one as poor.

Almost all studies accounted for basic sociodemographic confounders. Several also adjusted for comorbidities, alcohol/substance use disorders, medications, smoking status, and income/education level.

Pooled estimates from the meta-analyzed studies showed that only one showed no significant association between psychotic disorders and dementia, whereas 10 reported increased risk (pooled risk ratio, 2.52; 95% confidence interval, 1.67-3.80; I², 99.7%).

Subgroup analyses showed higher risk in participants with typical and late-onset psychotic disorders (pooled RR, 2.10; 95% CI, 2.33-4.14; I², 77.5%; P = .004) vs. those with very late onset schizophrenia-like psychoses (pooled RR, 2.77; 95% CI, 1.74-4.40 I², 98.9%; P < .001).

The effect was larger in studies with a follow-up of less than 10 years vs. those with a follow-up of 10 years or more, and it was also greater in studies conducted in non-European vs. European countries (all P < .001).

Studies with more female participants (≥ 60%) showed higher risk compared with those that had a lower percentage of female participants. Studies published during or after 2020 showed a stronger association than those published before 2020 (all P < .001).

There was also a higher risk for dementia in studies investigating broader nonaffective psychotic disorders compared with studies investigating only schizophrenia, in prospective vs. retrospective studies, and in studies with a minimum age of less than 60 years at baseline vs. a minimum age of 60 or older (all P < .001).

“Several possible mechanisms could underlie these findings, although we were not able to directly test these in our review,” Dr. Stafford said. She noted that psychotic disorders and other psychiatric diagnoses may cause dementia.

“People with psychotic disorders such as schizophrenia are also at higher risk of health conditions including cardiovascular disease and diabetes, which are known risk factors for dementia and could underpin these associations,” said Dr. Stafford.

It is also possible “that psychotic symptoms could be early markers of dementia for some people, rather than causes,” she added.
 

Neuroimaging evidence lacking

Commenting on the study, Dilip V. Jeste, MD, former senior associate dean for healthy aging and senior care and distinguished professor of psychiatry and neurosciences at the University of California, San Diego, complimented the investigators for “an excellent article on an important but difficult topic.”

Limitations “pertain not to the meta-analysis but to the original studies,” said Dr. Jeste, who was not involved with the review. Diagnosing dementia in individuals with psychotic disorders is “challenging because cognitive deficits and behavioral symptoms in psychotic disorders may be misdiagnosed as dementia in some individuals – and vice versa,” he added.

Moreover, the studies did not specify the type of dementia, such as Alzheimer’s disease, vascular, Lewy body, frontotemporal, or mixed. Together, “they account for 90% of the dementias, and most patients with these dementias have brain abnormalities that can clearly be seen on MRI,” Dr. Jeste said.

However, patients with schizophrenia who are diagnosed with dementia “rarely show severe brain atrophy, even in specific regions commonly observed in nonpsychotic people with these dementias,” Dr. Jeste noted.

Thus, objective neuroimaging-based evidence for dementia and its subtype “is lacking in most of the published studies of persons with psychotic disorders diagnosed as having dementia,” he said.

There is a “clear need for comprehensive studies of dementia in people with psychotic disorders to understand the significance of the results,” Dr. Jeste concluded.

The review did not receive any funding. Dr. Stafford was supported by an NIHR-UCLH BRC Postdoctoral Bridging Fellowship and the National Institute for Health Research Biomedical Research Centre at University College London Hospitals NHS Foundation Trust. Dr. Stafford was also the principal investigator in one of the studies meeting the inclusion criteria of the review. The other investigators and Dr. Jeste reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Patients with psychotic disorders such as schizophrenia are more than twice as likely as those without a psychotic disorder to eventually develop dementia, new research suggests.

Results from a review and meta-analysis of almost 13 million total participants from nine countries showed that, across multiple different psychotic disorders, there was a 2.5-fold higher risk of developing dementia later in life compared with individuals who did not have a disorder. This was regardless of the age at which the patients first developed the mental illness.

Moreover, participants with a psychotic disorder tended to be younger than average when diagnosed with dementia. Two studies showed that those with psychotic disorders were more likely to be diagnosed with dementia as early as in their 60s.

“The findings add to a growing body of evidence linking psychiatric disorders with later cognitive decline and dementia,” senior investigator Jean Stafford, PhD, a research fellow at MRC Unit for Lifelong Health and Ageing, University College London, told this news organization.

Dr. Stafford noted that the results highlight the importance of being aware of and watchful for symptoms of cognitive decline in patients with psychotic disorders in mid- and late life.

“In addition, given that people with psychotic disorders are at higher risk of experiencing multiple health conditions, including dementia, managing overall physical and mental health in this group is crucial,” she said.

The findings were published online in Psychological Medicine.
 

Bringing the evidence together

There is increasing evidence that multiple psychiatric symptoms and diagnoses are associated with cognitive decline and dementia, with particularly strong evidence for late-life depression, Dr. Stafford said.

“However, the relationship between psychotic disorders and dementia is less well-established,” she added.

Last year, her team published a study showing a strong association between very late onset psychotic disorders, defined as first diagnosed after age 60 years, and increased risk for dementia in Swedish population register data.

“We also became aware of several other large studies on the topic published in the last few years and realized that an up-to-date systematic review and meta-analysis was needed to bring together the evidence, specifically focusing on longitudinal studies,” Dr. Stafford said.

The researchers searched four databases of prospective and retrospective longitudinal studies published through March 2022. Studies were required to focus on adults aged 18 years or older with a clinical diagnosis of a nonaffective psychotic disorder and a comparison group consisting of adults without a nonaffective psychotic disorder.

Of 9,496 papers, the investigators selected 11 published from 2003 to 2022 that met criteria for inclusion in their meta-analysis (12,997,101 participants), with follow-up periods ranging from 1.57 to 33 years.

The studies hailed from Denmark, Finland, Sweden, the United Kingdom, the United States, Australia, Taiwan, New Zealand, and Israel.

Random-effects meta-analyses were used to pool estimates across studies. The researchers assessed the risk of bias for each study. They also included two additional studies in the review, but not the meta-analysis, that focused specifically on late-onset acute and transient psychosis and late-onset delusional disorder.

The other studies focused on late-onset schizophrenia and/or very late onset schizophrenia-like psychoses, schizophrenia, psychotic disorders, and schizophrenia in older people.

Most studies investigated the incidence of all-cause dementia, although one study focused on the incidence of Alzheimer’s disease.
 

Potential mechanisms

The narrative review showed that most studies (n = 10) were of high methodological quality, although two were rated as fair and one as poor.

Almost all studies accounted for basic sociodemographic confounders. Several also adjusted for comorbidities, alcohol/substance use disorders, medications, smoking status, and income/education level.

Pooled estimates from the meta-analyzed studies showed that only one showed no significant association between psychotic disorders and dementia, whereas 10 reported increased risk (pooled risk ratio, 2.52; 95% confidence interval, 1.67-3.80; I², 99.7%).

Subgroup analyses showed higher risk in participants with typical and late-onset psychotic disorders (pooled RR, 2.10; 95% CI, 2.33-4.14; I², 77.5%; P = .004) vs. those with very late onset schizophrenia-like psychoses (pooled RR, 2.77; 95% CI, 1.74-4.40 I², 98.9%; P < .001).

The effect was larger in studies with a follow-up of less than 10 years vs. those with a follow-up of 10 years or more, and it was also greater in studies conducted in non-European vs. European countries (all P < .001).

Studies with more female participants (≥ 60%) showed higher risk compared with those that had a lower percentage of female participants. Studies published during or after 2020 showed a stronger association than those published before 2020 (all P < .001).

There was also a higher risk for dementia in studies investigating broader nonaffective psychotic disorders compared with studies investigating only schizophrenia, in prospective vs. retrospective studies, and in studies with a minimum age of less than 60 years at baseline vs. a minimum age of 60 or older (all P < .001).

“Several possible mechanisms could underlie these findings, although we were not able to directly test these in our review,” Dr. Stafford said. She noted that psychotic disorders and other psychiatric diagnoses may cause dementia.

“People with psychotic disorders such as schizophrenia are also at higher risk of health conditions including cardiovascular disease and diabetes, which are known risk factors for dementia and could underpin these associations,” said Dr. Stafford.

It is also possible “that psychotic symptoms could be early markers of dementia for some people, rather than causes,” she added.
 

Neuroimaging evidence lacking

Commenting on the study, Dilip V. Jeste, MD, former senior associate dean for healthy aging and senior care and distinguished professor of psychiatry and neurosciences at the University of California, San Diego, complimented the investigators for “an excellent article on an important but difficult topic.”

Limitations “pertain not to the meta-analysis but to the original studies,” said Dr. Jeste, who was not involved with the review. Diagnosing dementia in individuals with psychotic disorders is “challenging because cognitive deficits and behavioral symptoms in psychotic disorders may be misdiagnosed as dementia in some individuals – and vice versa,” he added.

Moreover, the studies did not specify the type of dementia, such as Alzheimer’s disease, vascular, Lewy body, frontotemporal, or mixed. Together, “they account for 90% of the dementias, and most patients with these dementias have brain abnormalities that can clearly be seen on MRI,” Dr. Jeste said.

However, patients with schizophrenia who are diagnosed with dementia “rarely show severe brain atrophy, even in specific regions commonly observed in nonpsychotic people with these dementias,” Dr. Jeste noted.

Thus, objective neuroimaging-based evidence for dementia and its subtype “is lacking in most of the published studies of persons with psychotic disorders diagnosed as having dementia,” he said.

There is a “clear need for comprehensive studies of dementia in people with psychotic disorders to understand the significance of the results,” Dr. Jeste concluded.

The review did not receive any funding. Dr. Stafford was supported by an NIHR-UCLH BRC Postdoctoral Bridging Fellowship and the National Institute for Health Research Biomedical Research Centre at University College London Hospitals NHS Foundation Trust. Dr. Stafford was also the principal investigator in one of the studies meeting the inclusion criteria of the review. The other investigators and Dr. Jeste reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Patients with psychotic disorders such as schizophrenia are more than twice as likely as those without a psychotic disorder to eventually develop dementia, new research suggests.

Results from a review and meta-analysis of almost 13 million total participants from nine countries showed that, across multiple different psychotic disorders, there was a 2.5-fold higher risk of developing dementia later in life compared with individuals who did not have a disorder. This was regardless of the age at which the patients first developed the mental illness.

Moreover, participants with a psychotic disorder tended to be younger than average when diagnosed with dementia. Two studies showed that those with psychotic disorders were more likely to be diagnosed with dementia as early as in their 60s.

“The findings add to a growing body of evidence linking psychiatric disorders with later cognitive decline and dementia,” senior investigator Jean Stafford, PhD, a research fellow at MRC Unit for Lifelong Health and Ageing, University College London, told this news organization.

Dr. Stafford noted that the results highlight the importance of being aware of and watchful for symptoms of cognitive decline in patients with psychotic disorders in mid- and late life.

“In addition, given that people with psychotic disorders are at higher risk of experiencing multiple health conditions, including dementia, managing overall physical and mental health in this group is crucial,” she said.

The findings were published online in Psychological Medicine.
 

Bringing the evidence together

There is increasing evidence that multiple psychiatric symptoms and diagnoses are associated with cognitive decline and dementia, with particularly strong evidence for late-life depression, Dr. Stafford said.

“However, the relationship between psychotic disorders and dementia is less well-established,” she added.

Last year, her team published a study showing a strong association between very late onset psychotic disorders, defined as first diagnosed after age 60 years, and increased risk for dementia in Swedish population register data.

“We also became aware of several other large studies on the topic published in the last few years and realized that an up-to-date systematic review and meta-analysis was needed to bring together the evidence, specifically focusing on longitudinal studies,” Dr. Stafford said.

The researchers searched four databases of prospective and retrospective longitudinal studies published through March 2022. Studies were required to focus on adults aged 18 years or older with a clinical diagnosis of a nonaffective psychotic disorder and a comparison group consisting of adults without a nonaffective psychotic disorder.

Of 9,496 papers, the investigators selected 11 published from 2003 to 2022 that met criteria for inclusion in their meta-analysis (12,997,101 participants), with follow-up periods ranging from 1.57 to 33 years.

The studies hailed from Denmark, Finland, Sweden, the United Kingdom, the United States, Australia, Taiwan, New Zealand, and Israel.

Random-effects meta-analyses were used to pool estimates across studies. The researchers assessed the risk of bias for each study. They also included two additional studies in the review, but not the meta-analysis, that focused specifically on late-onset acute and transient psychosis and late-onset delusional disorder.

The other studies focused on late-onset schizophrenia and/or very late onset schizophrenia-like psychoses, schizophrenia, psychotic disorders, and schizophrenia in older people.

Most studies investigated the incidence of all-cause dementia, although one study focused on the incidence of Alzheimer’s disease.
 

Potential mechanisms

The narrative review showed that most studies (n = 10) were of high methodological quality, although two were rated as fair and one as poor.

Almost all studies accounted for basic sociodemographic confounders. Several also adjusted for comorbidities, alcohol/substance use disorders, medications, smoking status, and income/education level.

Pooled estimates from the meta-analyzed studies showed that only one showed no significant association between psychotic disorders and dementia, whereas 10 reported increased risk (pooled risk ratio, 2.52; 95% confidence interval, 1.67-3.80; I², 99.7%).

Subgroup analyses showed higher risk in participants with typical and late-onset psychotic disorders (pooled RR, 2.10; 95% CI, 2.33-4.14; I², 77.5%; P = .004) vs. those with very late onset schizophrenia-like psychoses (pooled RR, 2.77; 95% CI, 1.74-4.40 I², 98.9%; P < .001).

The effect was larger in studies with a follow-up of less than 10 years vs. those with a follow-up of 10 years or more, and it was also greater in studies conducted in non-European vs. European countries (all P < .001).

Studies with more female participants (≥ 60%) showed higher risk compared with those that had a lower percentage of female participants. Studies published during or after 2020 showed a stronger association than those published before 2020 (all P < .001).

There was also a higher risk for dementia in studies investigating broader nonaffective psychotic disorders compared with studies investigating only schizophrenia, in prospective vs. retrospective studies, and in studies with a minimum age of less than 60 years at baseline vs. a minimum age of 60 or older (all P < .001).

“Several possible mechanisms could underlie these findings, although we were not able to directly test these in our review,” Dr. Stafford said. She noted that psychotic disorders and other psychiatric diagnoses may cause dementia.

“People with psychotic disorders such as schizophrenia are also at higher risk of health conditions including cardiovascular disease and diabetes, which are known risk factors for dementia and could underpin these associations,” said Dr. Stafford.

It is also possible “that psychotic symptoms could be early markers of dementia for some people, rather than causes,” she added.
 

Neuroimaging evidence lacking

Commenting on the study, Dilip V. Jeste, MD, former senior associate dean for healthy aging and senior care and distinguished professor of psychiatry and neurosciences at the University of California, San Diego, complimented the investigators for “an excellent article on an important but difficult topic.”

Limitations “pertain not to the meta-analysis but to the original studies,” said Dr. Jeste, who was not involved with the review. Diagnosing dementia in individuals with psychotic disorders is “challenging because cognitive deficits and behavioral symptoms in psychotic disorders may be misdiagnosed as dementia in some individuals – and vice versa,” he added.

Moreover, the studies did not specify the type of dementia, such as Alzheimer’s disease, vascular, Lewy body, frontotemporal, or mixed. Together, “they account for 90% of the dementias, and most patients with these dementias have brain abnormalities that can clearly be seen on MRI,” Dr. Jeste said.

However, patients with schizophrenia who are diagnosed with dementia “rarely show severe brain atrophy, even in specific regions commonly observed in nonpsychotic people with these dementias,” Dr. Jeste noted.

Thus, objective neuroimaging-based evidence for dementia and its subtype “is lacking in most of the published studies of persons with psychotic disorders diagnosed as having dementia,” he said.

There is a “clear need for comprehensive studies of dementia in people with psychotic disorders to understand the significance of the results,” Dr. Jeste concluded.

The review did not receive any funding. Dr. Stafford was supported by an NIHR-UCLH BRC Postdoctoral Bridging Fellowship and the National Institute for Health Research Biomedical Research Centre at University College London Hospitals NHS Foundation Trust. Dr. Stafford was also the principal investigator in one of the studies meeting the inclusion criteria of the review. The other investigators and Dr. Jeste reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Drugs commonly used to treat erectile dysfunction (ED) are not associated with a decreased risk of Alzheimer’s disease and related dementias (ADRD), new research shows.

The findings contradict results from a previous study that suggested that individuals who take sildenafil (Viagra) were significantly less likely to develop Alzheimer’s.

The new research, part of a larger effort to identify existing medications that could be repurposed to treat ADRD, employed a study design that reduced the risk for potential bias that may have influenced the earlier findings, the investigators note.

“That study came out last fall and was widely covered in the media, and we thought there were some methodological shortcomings that might have explained the results,” lead investigator Rishi Desai, PhD, assistant professor of medicine at Harvard Medical School and an associate epidemiologist at Brigham and Women’s Hospital, both in Boston, said in an interview.

The new study was published online in Brain Communications.


 

Not the final word?

Animal studies suggest that phosphodiesterase-5 (PDE5) inhibitors, a drug class that includes the ED drugs sildenafil and tadalafil (Cialis), improve memory and cognitive function and reduce amyloid burden. But studies in humans have yielded conflicting results.*

Although the new research and the work published last year both drew on Medicare data, they examined different patient populations.

The first study compared those who took sildenafil for any reason to those who did not take it. That design likely resulted in an analysis of a comparison of individuals with ED – the most common indication for sildenafil – to generally older individuals with diabetes or hypertension, Dr. Desai said.

In contrast, the current study included only those with pulmonary arterial hypertension (PAH), which is also an indication for PDE5 inhibitors. The researchers compared ADRD incidence in those who took PDE5 inhibitors with the incidence among those who took a different medication to treat their PAH. They used propensity matching to create two groups with similar characteristics and examined the data using four analytic strategies.

The investigators found no significant difference between groups in the incidence of ADRD, regardless of the strategy they used. Cell culture studies also revealed no protective effect from PDE5 inhibitors.

“No study of this kind should claim the final word,” Dr. Desai said. “It is extremely difficult to nail down causality from these types of data sources.”
 

Impressive study design

Commenting on the findings, David Knopman, MD, professor of neurology at Mayo Clinic, Rochester, Minn., described the study design as “impressive” for its efforts to minimize bias, a key limitation in the previous study.

“It was always the case that the claims about sildenafil needed further developmental work prior to testing the drug in randomized controlled trials,” Dr. Knopman said. “The evidence for the use of the drug was never sufficient for clinicians to use it in their patients.”

The study was funded by National Institute on Aging. Dr. Desai is an investigator who receives research grants from Bayer, Vertex, and Novartis that were given to the Brigham and Women’s Hospital for unrelated projects. Dr. Knopman has disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Correction, 11/3/22: An earlier version of this article misstated the abbreviation for phosphodiesterase-5. It is PDE-5.

Drugs commonly used to treat erectile dysfunction (ED) are not associated with a decreased risk of Alzheimer’s disease and related dementias (ADRD), new research shows.

The findings contradict results from a previous study that suggested that individuals who take sildenafil (Viagra) were significantly less likely to develop Alzheimer’s.

The new research, part of a larger effort to identify existing medications that could be repurposed to treat ADRD, employed a study design that reduced the risk for potential bias that may have influenced the earlier findings, the investigators note.

“That study came out last fall and was widely covered in the media, and we thought there were some methodological shortcomings that might have explained the results,” lead investigator Rishi Desai, PhD, assistant professor of medicine at Harvard Medical School and an associate epidemiologist at Brigham and Women’s Hospital, both in Boston, said in an interview.

The new study was published online in Brain Communications.


 

Not the final word?

Animal studies suggest that phosphodiesterase-5 (PDE5) inhibitors, a drug class that includes the ED drugs sildenafil and tadalafil (Cialis), improve memory and cognitive function and reduce amyloid burden. But studies in humans have yielded conflicting results.*

Although the new research and the work published last year both drew on Medicare data, they examined different patient populations.

The first study compared those who took sildenafil for any reason to those who did not take it. That design likely resulted in an analysis of a comparison of individuals with ED – the most common indication for sildenafil – to generally older individuals with diabetes or hypertension, Dr. Desai said.

In contrast, the current study included only those with pulmonary arterial hypertension (PAH), which is also an indication for PDE5 inhibitors. The researchers compared ADRD incidence in those who took PDE5 inhibitors with the incidence among those who took a different medication to treat their PAH. They used propensity matching to create two groups with similar characteristics and examined the data using four analytic strategies.

The investigators found no significant difference between groups in the incidence of ADRD, regardless of the strategy they used. Cell culture studies also revealed no protective effect from PDE5 inhibitors.

“No study of this kind should claim the final word,” Dr. Desai said. “It is extremely difficult to nail down causality from these types of data sources.”
 

Impressive study design

Commenting on the findings, David Knopman, MD, professor of neurology at Mayo Clinic, Rochester, Minn., described the study design as “impressive” for its efforts to minimize bias, a key limitation in the previous study.

“It was always the case that the claims about sildenafil needed further developmental work prior to testing the drug in randomized controlled trials,” Dr. Knopman said. “The evidence for the use of the drug was never sufficient for clinicians to use it in their patients.”

The study was funded by National Institute on Aging. Dr. Desai is an investigator who receives research grants from Bayer, Vertex, and Novartis that were given to the Brigham and Women’s Hospital for unrelated projects. Dr. Knopman has disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Correction, 11/3/22: An earlier version of this article misstated the abbreviation for phosphodiesterase-5. It is PDE-5.

Drugs commonly used to treat erectile dysfunction (ED) are not associated with a decreased risk of Alzheimer’s disease and related dementias (ADRD), new research shows.

The findings contradict results from a previous study that suggested that individuals who take sildenafil (Viagra) were significantly less likely to develop Alzheimer’s.

The new research, part of a larger effort to identify existing medications that could be repurposed to treat ADRD, employed a study design that reduced the risk for potential bias that may have influenced the earlier findings, the investigators note.

“That study came out last fall and was widely covered in the media, and we thought there were some methodological shortcomings that might have explained the results,” lead investigator Rishi Desai, PhD, assistant professor of medicine at Harvard Medical School and an associate epidemiologist at Brigham and Women’s Hospital, both in Boston, said in an interview.

The new study was published online in Brain Communications.


 

Not the final word?

Animal studies suggest that phosphodiesterase-5 (PDE5) inhibitors, a drug class that includes the ED drugs sildenafil and tadalafil (Cialis), improve memory and cognitive function and reduce amyloid burden. But studies in humans have yielded conflicting results.*

Although the new research and the work published last year both drew on Medicare data, they examined different patient populations.

The first study compared those who took sildenafil for any reason to those who did not take it. That design likely resulted in an analysis of a comparison of individuals with ED – the most common indication for sildenafil – to generally older individuals with diabetes or hypertension, Dr. Desai said.

In contrast, the current study included only those with pulmonary arterial hypertension (PAH), which is also an indication for PDE5 inhibitors. The researchers compared ADRD incidence in those who took PDE5 inhibitors with the incidence among those who took a different medication to treat their PAH. They used propensity matching to create two groups with similar characteristics and examined the data using four analytic strategies.

The investigators found no significant difference between groups in the incidence of ADRD, regardless of the strategy they used. Cell culture studies also revealed no protective effect from PDE5 inhibitors.

“No study of this kind should claim the final word,” Dr. Desai said. “It is extremely difficult to nail down causality from these types of data sources.”
 

Impressive study design

Commenting on the findings, David Knopman, MD, professor of neurology at Mayo Clinic, Rochester, Minn., described the study design as “impressive” for its efforts to minimize bias, a key limitation in the previous study.

“It was always the case that the claims about sildenafil needed further developmental work prior to testing the drug in randomized controlled trials,” Dr. Knopman said. “The evidence for the use of the drug was never sufficient for clinicians to use it in their patients.”

The study was funded by National Institute on Aging. Dr. Desai is an investigator who receives research grants from Bayer, Vertex, and Novartis that were given to the Brigham and Women’s Hospital for unrelated projects. Dr. Knopman has disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Correction, 11/3/22: An earlier version of this article misstated the abbreviation for phosphodiesterase-5. It is PDE-5.

A 67-year-old man asks about what he can do to prevent dementia. He reports his mother had dementia, and he wants to do everything he can to prevent it. Which of the following has evidence of benefit?

A) Thiamine

B) Vitamin E

C) Multivitamin (MV)

D) Keto diet

E) Red wine
 

FDA-approved therapies for dementia

To date the actual therapies for dementia have been disappointing. Donepezil, the most prescribed medication for the treatment of dementia has a number-needed-to treat (NNT) over 17, and causes frequent side effects. Aducanumab was recently approved by the Food and Drug Administration for the treatment of Alzheimer’s disease (AD), but controversy has arisen, as the clinical results were modest, and the price tag will be large – estimated at $30,000-$50,000/year.

Preventive options that may decrease the likelihood of dementia

Patients often ask the question stated above. Regarding how to respond to that question, choice C, MV, has some recent evidence of benefit. Baker and colleagues studied the effect of cocoa extract and multivitamins on cognitive function in the COSMOS-Mind trial.¹ A total of 2,262 people were enrolled, and over 90% completed baseline and at least one annual cognitive assessment. Cocoa extract had no impact on global cognition (confidence interval [CI], –.02-.08, P = .28), but MV supplementation did have a statistically significant impact on global cognition (CI, .02-.12, P less than .007).

Vitamin E has been enthusiastically endorsed in the past as a treatment to prevent cognitive decline. The most recent Cochrane review on vitamin E concluded there was no evidence that the alpha-tocopherol form of vitamin E given to people with MCI prevents progression to dementia, or that it improves cognitive function in people with MCI or dementia due to AD.²

Exercise has long been a mainstay of our advice to patients as something they can do to help prevent dementia. Yu and colleagues did a meta-analysis of almost 400 randomized controlled trials and observational studies to grade the evidence on different interventions.³ They gave exercise a grade B for evidence of benefit.

A recent study addressed this issue, and I think it is helpful on quantifying how much exercise is needed. Del Pozo Cruz and colleagues did a prospective population-based cohort study of 78,000 adults aged 40-79, with an average of 6.9 years of follow up.⁴ The optimal step count was 9,826 steps (hazard ratio [HR], 0.49; 95% CI, 0.39-0.62) and the minimal step count for benefit was 3,826 steps (HR, 0.75; 95% CI, 0.67-0.83).
 

Modifiable factors

The other major modifiable factors to consider are problems with special senses. Both vision loss and hearing loss have been associated with cognitive impairment.

Shang and colleagues published a meta-analysis of 14 cohort studies addressing vision impairment and cognitive function involving more than 6 million individuals.⁵ They concluded that vision impairment is associated with an increased risk of both dementia and cognitive impairment in older adults.

Loughrey and colleagues performed a meta-analysis of 36 studies addressing hearing loss and cognitive decline.⁶ They reported that, among cross-sectional studies, a significant association was found for cognitive impairment (odds ratio [OR], 2.00; 95% CI, 1.39-2.89) and dementia (OR, 2.42; 95% CI, 1.24-4.72). A similar finding was present in prospective cohort studies with a significant association being found for cognitive impairment (OR, 1.22; 95% CI, 1.09-1.36) and dementia (OR, 1.28; 95% CI, 1.02-1.59).

A 25-year prospective, population-based study of patients with hearing loss revealed a difference in the rate of change in MMSE score over the 25-year follow-up between participants with hearing loss not using hearing aids matched with controls who didn’t have hearing loss. Those with untreated hearing loss had more cognitive decline than that of patients without hearing loss.⁷ The subjects with hearing loss using a hearing aid had no difference in cognitive decline from controls.
 

Pearl

Several simple and safe interventions may protect our patients from cognitive decline. These include taking a daily multivitamin, walking more than 4,000 steps a day, and optimizing vision and hearing.

Dr. Paauw is professor of medicine in the division of general internal medicine at the University of Washington, Seattle, and he serves as third-year medical student clerkship director at the University of Washington. Contact Dr. Paauw at [email protected].

References

1. Baker LD et al. Effects of cocoa extract and a multivitamin on cognitive function: A randomized clinical trial. Alzheimer’s Dement. 2022 Sep 14. doi: 10.1002/alz.12767.

2. Farina N et al. Vitamin E for Alzheimer’s dementia and mild cognitive impairment. Cochrane Database Syst Rev. 2017 Apr 18;4(4):CD002854. doi: 10.1002/14651858.CD002854.pub5.

3. Yu JT et al. Evidence-based prevention of Alzheimer’s disease: Systematic review and meta-analysis of 243 observational prospective studies and 153 randomised controlled trials. J Neurol Neurosurg Psychiatry. 2020 Nov;91(11):1201-9.

4. Del Pozo Cruz B et al. Association of daily step count and intensity with incident dementia in 78,430 adults living in the UK. JAMA Neurol. 2022 Oct 1;79(10):1059-63.

5. Shang X et al. The association between vision impairment and incidence of dementia and cognitive impairment: A systematic review and meta-analysis. Ophthalmology. 2021 Aug;128(8):1135-49.

6. Loughrey DG et al. Association of age-related hearing loss with cognitive function, cognitive impairment, and dementia: A systematic review and meta-analysis. JAMA Otolaryngol Head Neck Surg. 2018 Feb 1;144(2):115-26.

7. Amieva H et al. Self-reported hearing loss, hearing aids, and cognitive decline in elderly adults: A 25-year study. J Am Geriatr Soc. 2015 Oct;63(10):2099-104.

A 67-year-old man asks about what he can do to prevent dementia. He reports his mother had dementia, and he wants to do everything he can to prevent it. Which of the following has evidence of benefit?

A) Thiamine

B) Vitamin E

C) Multivitamin (MV)

D) Keto diet

E) Red wine
 

FDA-approved therapies for dementia

To date the actual therapies for dementia have been disappointing. Donepezil, the most prescribed medication for the treatment of dementia has a number-needed-to treat (NNT) over 17, and causes frequent side effects. Aducanumab was recently approved by the Food and Drug Administration for the treatment of Alzheimer’s disease (AD), but controversy has arisen, as the clinical results were modest, and the price tag will be large – estimated at $30,000-$50,000/year.

Preventive options that may decrease the likelihood of dementia

Patients often ask the question stated above. Regarding how to respond to that question, choice C, MV, has some recent evidence of benefit. Baker and colleagues studied the effect of cocoa extract and multivitamins on cognitive function in the COSMOS-Mind trial.¹ A total of 2,262 people were enrolled, and over 90% completed baseline and at least one annual cognitive assessment. Cocoa extract had no impact on global cognition (confidence interval [CI], –.02-.08, P = .28), but MV supplementation did have a statistically significant impact on global cognition (CI, .02-.12, P less than .007).

Vitamin E has been enthusiastically endorsed in the past as a treatment to prevent cognitive decline. The most recent Cochrane review on vitamin E concluded there was no evidence that the alpha-tocopherol form of vitamin E given to people with MCI prevents progression to dementia, or that it improves cognitive function in people with MCI or dementia due to AD.²

Exercise has long been a mainstay of our advice to patients as something they can do to help prevent dementia. Yu and colleagues did a meta-analysis of almost 400 randomized controlled trials and observational studies to grade the evidence on different interventions.³ They gave exercise a grade B for evidence of benefit.

A recent study addressed this issue, and I think it is helpful on quantifying how much exercise is needed. Del Pozo Cruz and colleagues did a prospective population-based cohort study of 78,000 adults aged 40-79, with an average of 6.9 years of follow up.⁴ The optimal step count was 9,826 steps (hazard ratio [HR], 0.49; 95% CI, 0.39-0.62) and the minimal step count for benefit was 3,826 steps (HR, 0.75; 95% CI, 0.67-0.83).
 

Modifiable factors

The other major modifiable factors to consider are problems with special senses. Both vision loss and hearing loss have been associated with cognitive impairment.

Shang and colleagues published a meta-analysis of 14 cohort studies addressing vision impairment and cognitive function involving more than 6 million individuals.⁵ They concluded that vision impairment is associated with an increased risk of both dementia and cognitive impairment in older adults.

Loughrey and colleagues performed a meta-analysis of 36 studies addressing hearing loss and cognitive decline.⁶ They reported that, among cross-sectional studies, a significant association was found for cognitive impairment (odds ratio [OR], 2.00; 95% CI, 1.39-2.89) and dementia (OR, 2.42; 95% CI, 1.24-4.72). A similar finding was present in prospective cohort studies with a significant association being found for cognitive impairment (OR, 1.22; 95% CI, 1.09-1.36) and dementia (OR, 1.28; 95% CI, 1.02-1.59).

A 25-year prospective, population-based study of patients with hearing loss revealed a difference in the rate of change in MMSE score over the 25-year follow-up between participants with hearing loss not using hearing aids matched with controls who didn’t have hearing loss. Those with untreated hearing loss had more cognitive decline than that of patients without hearing loss.⁷ The subjects with hearing loss using a hearing aid had no difference in cognitive decline from controls.
 

Pearl

Several simple and safe interventions may protect our patients from cognitive decline. These include taking a daily multivitamin, walking more than 4,000 steps a day, and optimizing vision and hearing.

Dr. Paauw is professor of medicine in the division of general internal medicine at the University of Washington, Seattle, and he serves as third-year medical student clerkship director at the University of Washington. Contact Dr. Paauw at [email protected].

References

1. Baker LD et al. Effects of cocoa extract and a multivitamin on cognitive function: A randomized clinical trial. Alzheimer’s Dement. 2022 Sep 14. doi: 10.1002/alz.12767.

2. Farina N et al. Vitamin E for Alzheimer’s dementia and mild cognitive impairment. Cochrane Database Syst Rev. 2017 Apr 18;4(4):CD002854. doi: 10.1002/14651858.CD002854.pub5.

3. Yu JT et al. Evidence-based prevention of Alzheimer’s disease: Systematic review and meta-analysis of 243 observational prospective studies and 153 randomised controlled trials. J Neurol Neurosurg Psychiatry. 2020 Nov;91(11):1201-9.

4. Del Pozo Cruz B et al. Association of daily step count and intensity with incident dementia in 78,430 adults living in the UK. JAMA Neurol. 2022 Oct 1;79(10):1059-63.

5. Shang X et al. The association between vision impairment and incidence of dementia and cognitive impairment: A systematic review and meta-analysis. Ophthalmology. 2021 Aug;128(8):1135-49.

6. Loughrey DG et al. Association of age-related hearing loss with cognitive function, cognitive impairment, and dementia: A systematic review and meta-analysis. JAMA Otolaryngol Head Neck Surg. 2018 Feb 1;144(2):115-26.

7. Amieva H et al. Self-reported hearing loss, hearing aids, and cognitive decline in elderly adults: A 25-year study. J Am Geriatr Soc. 2015 Oct;63(10):2099-104.

A 67-year-old man asks about what he can do to prevent dementia. He reports his mother had dementia, and he wants to do everything he can to prevent it. Which of the following has evidence of benefit?

A) Thiamine

B) Vitamin E

C) Multivitamin (MV)

D) Keto diet

E) Red wine
 

FDA-approved therapies for dementia

To date the actual therapies for dementia have been disappointing. Donepezil, the most prescribed medication for the treatment of dementia has a number-needed-to treat (NNT) over 17, and causes frequent side effects. Aducanumab was recently approved by the Food and Drug Administration for the treatment of Alzheimer’s disease (AD), but controversy has arisen, as the clinical results were modest, and the price tag will be large – estimated at $30,000-$50,000/year.

Preventive options that may decrease the likelihood of dementia

Patients often ask the question stated above. Regarding how to respond to that question, choice C, MV, has some recent evidence of benefit. Baker and colleagues studied the effect of cocoa extract and multivitamins on cognitive function in the COSMOS-Mind trial.¹ A total of 2,262 people were enrolled, and over 90% completed baseline and at least one annual cognitive assessment. Cocoa extract had no impact on global cognition (confidence interval [CI], –.02-.08, P = .28), but MV supplementation did have a statistically significant impact on global cognition (CI, .02-.12, P less than .007).

Vitamin E has been enthusiastically endorsed in the past as a treatment to prevent cognitive decline. The most recent Cochrane review on vitamin E concluded there was no evidence that the alpha-tocopherol form of vitamin E given to people with MCI prevents progression to dementia, or that it improves cognitive function in people with MCI or dementia due to AD.²

Exercise has long been a mainstay of our advice to patients as something they can do to help prevent dementia. Yu and colleagues did a meta-analysis of almost 400 randomized controlled trials and observational studies to grade the evidence on different interventions.³ They gave exercise a grade B for evidence of benefit.

A recent study addressed this issue, and I think it is helpful on quantifying how much exercise is needed. Del Pozo Cruz and colleagues did a prospective population-based cohort study of 78,000 adults aged 40-79, with an average of 6.9 years of follow up.⁴ The optimal step count was 9,826 steps (hazard ratio [HR], 0.49; 95% CI, 0.39-0.62) and the minimal step count for benefit was 3,826 steps (HR, 0.75; 95% CI, 0.67-0.83).
 

Modifiable factors

The other major modifiable factors to consider are problems with special senses. Both vision loss and hearing loss have been associated with cognitive impairment.

Shang and colleagues published a meta-analysis of 14 cohort studies addressing vision impairment and cognitive function involving more than 6 million individuals.⁵ They concluded that vision impairment is associated with an increased risk of both dementia and cognitive impairment in older adults.

Loughrey and colleagues performed a meta-analysis of 36 studies addressing hearing loss and cognitive decline.⁶ They reported that, among cross-sectional studies, a significant association was found for cognitive impairment (odds ratio [OR], 2.00; 95% CI, 1.39-2.89) and dementia (OR, 2.42; 95% CI, 1.24-4.72). A similar finding was present in prospective cohort studies with a significant association being found for cognitive impairment (OR, 1.22; 95% CI, 1.09-1.36) and dementia (OR, 1.28; 95% CI, 1.02-1.59).

A 25-year prospective, population-based study of patients with hearing loss revealed a difference in the rate of change in MMSE score over the 25-year follow-up between participants with hearing loss not using hearing aids matched with controls who didn’t have hearing loss. Those with untreated hearing loss had more cognitive decline than that of patients without hearing loss.⁷ The subjects with hearing loss using a hearing aid had no difference in cognitive decline from controls.
 

Pearl

Several simple and safe interventions may protect our patients from cognitive decline. These include taking a daily multivitamin, walking more than 4,000 steps a day, and optimizing vision and hearing.

Dr. Paauw is professor of medicine in the division of general internal medicine at the University of Washington, Seattle, and he serves as third-year medical student clerkship director at the University of Washington. Contact Dr. Paauw at [email protected].

References

1. Baker LD et al. Effects of cocoa extract and a multivitamin on cognitive function: A randomized clinical trial. Alzheimer’s Dement. 2022 Sep 14. doi: 10.1002/alz.12767.

2. Farina N et al. Vitamin E for Alzheimer’s dementia and mild cognitive impairment. Cochrane Database Syst Rev. 2017 Apr 18;4(4):CD002854. doi: 10.1002/14651858.CD002854.pub5.

3. Yu JT et al. Evidence-based prevention of Alzheimer’s disease: Systematic review and meta-analysis of 243 observational prospective studies and 153 randomised controlled trials. J Neurol Neurosurg Psychiatry. 2020 Nov;91(11):1201-9.

4. Del Pozo Cruz B et al. Association of daily step count and intensity with incident dementia in 78,430 adults living in the UK. JAMA Neurol. 2022 Oct 1;79(10):1059-63.

5. Shang X et al. The association between vision impairment and incidence of dementia and cognitive impairment: A systematic review and meta-analysis. Ophthalmology. 2021 Aug;128(8):1135-49.

6. Loughrey DG et al. Association of age-related hearing loss with cognitive function, cognitive impairment, and dementia: A systematic review and meta-analysis. JAMA Otolaryngol Head Neck Surg. 2018 Feb 1;144(2):115-26.

7. Amieva H et al. Self-reported hearing loss, hearing aids, and cognitive decline in elderly adults: A 25-year study. J Am Geriatr Soc. 2015 Oct;63(10):2099-104.

Contrary to some prior studies, new research suggests that a healthy diet, including the Mediterranean diet, does not reduce dementia risk.

After adjusting for relevant demographic and other lifestyle measures, there was no association between adherence to healthy dietary advice or the Mediterranean diet on the future risk of dementia or amyloid-beta (Abeta) accumulation.

OksanaKiian/Getty Images

“While our study does not rule out a possible association between diet and dementia, we did not find a link in our study, which had a long follow-up period, included younger participants than some other studies and did not require people to remember what foods they had eaten regularly years before,” study investigator Isabelle Glans, MD, of Lund (Sweden) University, said in a news release.

The findings were published online in Neurology.
 

No risk reduction

Several studies have investigated how dietary habits affect dementia risk, with inconsistent results.

The new findings are based on 28,025 adults (61% women; mean age, 58 years at baseline) who were free of dementia at baseline and were followed over a 20-year period as part of the Swedish Malmö Diet and Cancer Study. Dietary habits were assessed with a 7-day food diary, detailed food frequency questionnaire, and in-person interview.

During follow-up, 1,943 individuals (6.9%) developed dementia.

Compared with those who did not develop dementia, those who did develop dementia during follow-up were older and had a lower level of education and more cardiovascular risk factors and comorbidities at baseline.

Individuals who adhered to conventional healthy dietary recommendations did not have a lower risk of developing all-cause dementia (hazard ratio comparing worst with best adherence, 0.93; 95% confidence interval, 0.81-1.08), Alzheimer’s disease (HR, 1.03; 95% CI, 0.85-1.23) or vascular dementia (HR, 0.93; 95% CI, 0.69-1.26).

Adherence to the modified Mediterranean diet also did not appear to lower the risk of all-cause dementia (HR, 0.93; 95% CI, 0.75-1.15), Alzheimer’s disease (HR, 0.90; 95% CI, 0.68-1.19), or vascular dementia (HR, 1.00; 95% CI, 0.65-1.55).

There was also no significant association between diet and Alzheimer’s disease–related pathology, as measured by cerebrospinal fluid analysis of Abeta42 in a subgroup of 738 participants. Various sensitivity analyses yielded similar results.
 

Diet still matters

The authors of an accompanying editorial noted that diet as a “singular factor may not have a strong enough effect on cognition, but is more likely to be considered as one factor embedded with various others, the sum of which may influence the course of cognitive function (diet, regular exercise, vascular risk factor control, avoiding cigarette smoking, drinking alcohol in moderation, etc).

“Diet should not be forgotten and it still matters” but should be regarded as “one part of a multidomain intervention with respect to cognitive performance,” wrote Nils Peters, MD, with the University of Basel (Switzerland), and Benedetta Nacmias, PhD, with the University of Florence (Italy)).

“Key questions that remain include how to provide evidence for promoting the implications of dietary habits on cognition? Overall, dietary strategies will most likely be implicated either in order to reduce the increasing number of older subjects with dementia, or to extend healthy life expectancy, or both,” Dr. Peters and Dr. Nacmias said.

The study had no commercial funding. Dr. Glans, Dr. Peters, and Dr. Nacmias disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Contrary to some prior studies, new research suggests that a healthy diet, including the Mediterranean diet, does not reduce dementia risk.

After adjusting for relevant demographic and other lifestyle measures, there was no association between adherence to healthy dietary advice or the Mediterranean diet on the future risk of dementia or amyloid-beta (Abeta) accumulation.

OksanaKiian/Getty Images

“While our study does not rule out a possible association between diet and dementia, we did not find a link in our study, which had a long follow-up period, included younger participants than some other studies and did not require people to remember what foods they had eaten regularly years before,” study investigator Isabelle Glans, MD, of Lund (Sweden) University, said in a news release.

The findings were published online in Neurology.
 

No risk reduction

Several studies have investigated how dietary habits affect dementia risk, with inconsistent results.

The new findings are based on 28,025 adults (61% women; mean age, 58 years at baseline) who were free of dementia at baseline and were followed over a 20-year period as part of the Swedish Malmö Diet and Cancer Study. Dietary habits were assessed with a 7-day food diary, detailed food frequency questionnaire, and in-person interview.

During follow-up, 1,943 individuals (6.9%) developed dementia.

Compared with those who did not develop dementia, those who did develop dementia during follow-up were older and had a lower level of education and more cardiovascular risk factors and comorbidities at baseline.

Individuals who adhered to conventional healthy dietary recommendations did not have a lower risk of developing all-cause dementia (hazard ratio comparing worst with best adherence, 0.93; 95% confidence interval, 0.81-1.08), Alzheimer’s disease (HR, 1.03; 95% CI, 0.85-1.23) or vascular dementia (HR, 0.93; 95% CI, 0.69-1.26).

Adherence to the modified Mediterranean diet also did not appear to lower the risk of all-cause dementia (HR, 0.93; 95% CI, 0.75-1.15), Alzheimer’s disease (HR, 0.90; 95% CI, 0.68-1.19), or vascular dementia (HR, 1.00; 95% CI, 0.65-1.55).

There was also no significant association between diet and Alzheimer’s disease–related pathology, as measured by cerebrospinal fluid analysis of Abeta42 in a subgroup of 738 participants. Various sensitivity analyses yielded similar results.
 

Diet still matters

The authors of an accompanying editorial noted that diet as a “singular factor may not have a strong enough effect on cognition, but is more likely to be considered as one factor embedded with various others, the sum of which may influence the course of cognitive function (diet, regular exercise, vascular risk factor control, avoiding cigarette smoking, drinking alcohol in moderation, etc).

“Diet should not be forgotten and it still matters” but should be regarded as “one part of a multidomain intervention with respect to cognitive performance,” wrote Nils Peters, MD, with the University of Basel (Switzerland), and Benedetta Nacmias, PhD, with the University of Florence (Italy)).

“Key questions that remain include how to provide evidence for promoting the implications of dietary habits on cognition? Overall, dietary strategies will most likely be implicated either in order to reduce the increasing number of older subjects with dementia, or to extend healthy life expectancy, or both,” Dr. Peters and Dr. Nacmias said.

The study had no commercial funding. Dr. Glans, Dr. Peters, and Dr. Nacmias disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Contrary to some prior studies, new research suggests that a healthy diet, including the Mediterranean diet, does not reduce dementia risk.

After adjusting for relevant demographic and other lifestyle measures, there was no association between adherence to healthy dietary advice or the Mediterranean diet on the future risk of dementia or amyloid-beta (Abeta) accumulation.

OksanaKiian/Getty Images

“While our study does not rule out a possible association between diet and dementia, we did not find a link in our study, which had a long follow-up period, included younger participants than some other studies and did not require people to remember what foods they had eaten regularly years before,” study investigator Isabelle Glans, MD, of Lund (Sweden) University, said in a news release.

The findings were published online in Neurology.
 

No risk reduction

Several studies have investigated how dietary habits affect dementia risk, with inconsistent results.

The new findings are based on 28,025 adults (61% women; mean age, 58 years at baseline) who were free of dementia at baseline and were followed over a 20-year period as part of the Swedish Malmö Diet and Cancer Study. Dietary habits were assessed with a 7-day food diary, detailed food frequency questionnaire, and in-person interview.

During follow-up, 1,943 individuals (6.9%) developed dementia.

Compared with those who did not develop dementia, those who did develop dementia during follow-up were older and had a lower level of education and more cardiovascular risk factors and comorbidities at baseline.

Individuals who adhered to conventional healthy dietary recommendations did not have a lower risk of developing all-cause dementia (hazard ratio comparing worst with best adherence, 0.93; 95% confidence interval, 0.81-1.08), Alzheimer’s disease (HR, 1.03; 95% CI, 0.85-1.23) or vascular dementia (HR, 0.93; 95% CI, 0.69-1.26).

Adherence to the modified Mediterranean diet also did not appear to lower the risk of all-cause dementia (HR, 0.93; 95% CI, 0.75-1.15), Alzheimer’s disease (HR, 0.90; 95% CI, 0.68-1.19), or vascular dementia (HR, 1.00; 95% CI, 0.65-1.55).

There was also no significant association between diet and Alzheimer’s disease–related pathology, as measured by cerebrospinal fluid analysis of Abeta42 in a subgroup of 738 participants. Various sensitivity analyses yielded similar results.
 

Diet still matters

The authors of an accompanying editorial noted that diet as a “singular factor may not have a strong enough effect on cognition, but is more likely to be considered as one factor embedded with various others, the sum of which may influence the course of cognitive function (diet, regular exercise, vascular risk factor control, avoiding cigarette smoking, drinking alcohol in moderation, etc).

“Diet should not be forgotten and it still matters” but should be regarded as “one part of a multidomain intervention with respect to cognitive performance,” wrote Nils Peters, MD, with the University of Basel (Switzerland), and Benedetta Nacmias, PhD, with the University of Florence (Italy)).

“Key questions that remain include how to provide evidence for promoting the implications of dietary habits on cognition? Overall, dietary strategies will most likely be implicated either in order to reduce the increasing number of older subjects with dementia, or to extend healthy life expectancy, or both,” Dr. Peters and Dr. Nacmias said.

The study had no commercial funding. Dr. Glans, Dr. Peters, and Dr. Nacmias disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.