Alzheimer's & Cognition

TOPLINE:

Loneliness is associated with a higher risk of developing Parkinson’s disease (PD) across demographic groups and independent of other risk factors, data from nearly 500,000 U.K. adults suggest.

METHODOLOGY:

• Loneliness is associated with illness and death, including higher risk of neurodegenerative diseases, but no study has examined whether the association between loneliness and detrimental outcomes extends to PD.
• The current analysis included 491,603 U.K. Biobank participants (mean age, 56; 54% women) without a diagnosis of PD at baseline.
• Loneliness was assessed by a single question at baseline and incident PD was ascertained via health records over 15 years.
• Researchers assessed whether the association between loneliness and PD was moderated by age, sex, or genetic risk and whether the association was accounted for by sociodemographic factors; behavioral, mental, physical, or social factors; or genetic risk.

TAKEAWAY:

• Roughly 19% of the cohort reported being lonely. Compared with those who were not lonely, those who did report being lonely were slightly younger and were more likely to be women. They also had fewer resources, more health risk behaviors (current smoker and physically inactive), and worse physical and mental health.
• Over 15+ years of follow-up, 2,822 participants developed PD (incidence rate: 47 per 100,000 person-years). Compared with those who did not develop PD, those who did were older and more likely to be male, former smokers, have higher BMI and PD polygenetic risk score, and to have diabetes, hypertension, myocardial infarction or stroke, anxiety, or depression.
• In the primary analysis, individuals who reported being lonely had a higher risk for PD (hazard ratio, 1.37) – an association that remained after accounting for demographic and socioeconomic status, social isolation, PD polygenetic risk score, smoking, physical activity, BMI, diabetes, hypertension, stroke, myocardial infarction, depression, and having ever seen a psychiatrist (fully adjusted HR, 1.25). 
• The association between loneliness and incident PD was not moderated by sex, age, or polygenetic risk score.
• Contrary to expectations for a prodromal syndrome, loneliness was not associated with incident PD in the first 5 years after baseline but was associated with PD risk in the subsequent 10 years of follow-up (HR, 1.32).

IN PRACTICE:

“Our findings complement other evidence that loneliness is a psychosocial determinant of health associated with increased risk of morbidity and mortality [and] supports recent calls for the protective and healing effects of personally meaningful social connection,” the authors write.

SOURCE:

The study, with first author Antonio Terracciano, PhD, of Florida State University College of Medicine, Tallahassee, was published online  in JAMA Neurology.

LIMITATIONS:

This observational study could not determine causality or whether reverse causality could explain the association. Loneliness was assessed by a single yes/no question. PD diagnosis relied on hospital admission and death records and may have missed early PD diagnoses.

DISCLOSURES:

Funding for the study was provided by the National Institutes of Health and National Institute on Aging. The authors report no relevant financial relationships.

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

TOPLINE:

Loneliness is associated with a higher risk of developing Parkinson’s disease (PD) across demographic groups and independent of other risk factors, data from nearly 500,000 U.K. adults suggest.

METHODOLOGY:

• Loneliness is associated with illness and death, including higher risk of neurodegenerative diseases, but no study has examined whether the association between loneliness and detrimental outcomes extends to PD.
• The current analysis included 491,603 U.K. Biobank participants (mean age, 56; 54% women) without a diagnosis of PD at baseline.
• Loneliness was assessed by a single question at baseline and incident PD was ascertained via health records over 15 years.
• Researchers assessed whether the association between loneliness and PD was moderated by age, sex, or genetic risk and whether the association was accounted for by sociodemographic factors; behavioral, mental, physical, or social factors; or genetic risk.

TAKEAWAY:

• Roughly 19% of the cohort reported being lonely. Compared with those who were not lonely, those who did report being lonely were slightly younger and were more likely to be women. They also had fewer resources, more health risk behaviors (current smoker and physically inactive), and worse physical and mental health.
• Over 15+ years of follow-up, 2,822 participants developed PD (incidence rate: 47 per 100,000 person-years). Compared with those who did not develop PD, those who did were older and more likely to be male, former smokers, have higher BMI and PD polygenetic risk score, and to have diabetes, hypertension, myocardial infarction or stroke, anxiety, or depression.
• In the primary analysis, individuals who reported being lonely had a higher risk for PD (hazard ratio, 1.37) – an association that remained after accounting for demographic and socioeconomic status, social isolation, PD polygenetic risk score, smoking, physical activity, BMI, diabetes, hypertension, stroke, myocardial infarction, depression, and having ever seen a psychiatrist (fully adjusted HR, 1.25). 
• The association between loneliness and incident PD was not moderated by sex, age, or polygenetic risk score.
• Contrary to expectations for a prodromal syndrome, loneliness was not associated with incident PD in the first 5 years after baseline but was associated with PD risk in the subsequent 10 years of follow-up (HR, 1.32).

IN PRACTICE:

“Our findings complement other evidence that loneliness is a psychosocial determinant of health associated with increased risk of morbidity and mortality [and] supports recent calls for the protective and healing effects of personally meaningful social connection,” the authors write.

SOURCE:

The study, with first author Antonio Terracciano, PhD, of Florida State University College of Medicine, Tallahassee, was published online  in JAMA Neurology.

LIMITATIONS:

This observational study could not determine causality or whether reverse causality could explain the association. Loneliness was assessed by a single yes/no question. PD diagnosis relied on hospital admission and death records and may have missed early PD diagnoses.

DISCLOSURES:

Funding for the study was provided by the National Institutes of Health and National Institute on Aging. The authors report no relevant financial relationships.

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

TOPLINE:

Loneliness is associated with a higher risk of developing Parkinson’s disease (PD) across demographic groups and independent of other risk factors, data from nearly 500,000 U.K. adults suggest.

METHODOLOGY:

• Loneliness is associated with illness and death, including higher risk of neurodegenerative diseases, but no study has examined whether the association between loneliness and detrimental outcomes extends to PD.
• The current analysis included 491,603 U.K. Biobank participants (mean age, 56; 54% women) without a diagnosis of PD at baseline.
• Loneliness was assessed by a single question at baseline and incident PD was ascertained via health records over 15 years.
• Researchers assessed whether the association between loneliness and PD was moderated by age, sex, or genetic risk and whether the association was accounted for by sociodemographic factors; behavioral, mental, physical, or social factors; or genetic risk.

TAKEAWAY:

• Roughly 19% of the cohort reported being lonely. Compared with those who were not lonely, those who did report being lonely were slightly younger and were more likely to be women. They also had fewer resources, more health risk behaviors (current smoker and physically inactive), and worse physical and mental health.
• Over 15+ years of follow-up, 2,822 participants developed PD (incidence rate: 47 per 100,000 person-years). Compared with those who did not develop PD, those who did were older and more likely to be male, former smokers, have higher BMI and PD polygenetic risk score, and to have diabetes, hypertension, myocardial infarction or stroke, anxiety, or depression.
• In the primary analysis, individuals who reported being lonely had a higher risk for PD (hazard ratio, 1.37) – an association that remained after accounting for demographic and socioeconomic status, social isolation, PD polygenetic risk score, smoking, physical activity, BMI, diabetes, hypertension, stroke, myocardial infarction, depression, and having ever seen a psychiatrist (fully adjusted HR, 1.25). 
• The association between loneliness and incident PD was not moderated by sex, age, or polygenetic risk score.
• Contrary to expectations for a prodromal syndrome, loneliness was not associated with incident PD in the first 5 years after baseline but was associated with PD risk in the subsequent 10 years of follow-up (HR, 1.32).

IN PRACTICE:

“Our findings complement other evidence that loneliness is a psychosocial determinant of health associated with increased risk of morbidity and mortality [and] supports recent calls for the protective and healing effects of personally meaningful social connection,” the authors write.

SOURCE:

The study, with first author Antonio Terracciano, PhD, of Florida State University College of Medicine, Tallahassee, was published online  in JAMA Neurology.

LIMITATIONS:

This observational study could not determine causality or whether reverse causality could explain the association. Loneliness was assessed by a single yes/no question. PD diagnosis relied on hospital admission and death records and may have missed early PD diagnoses.

DISCLOSURES:

Funding for the study was provided by the National Institutes of Health and National Institute on Aging. The authors report no relevant financial relationships.

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

I have written before about the COSMOS study and its finding that multivitamins (and chocolate) did not improve brain or cardiovascular health. So I was surprised to read that a “new” study found that vitamins can forestall dementia and age-related cognitive decline.

Upon closer look, the new data are neither new nor convincing, at least to me.

©Graça Victoria/iStockphoto.com

Chocolate and multivitamins for CVD and cancer prevention

The large randomized COSMOS trial was supposed to be the definitive study on chocolate that would establish its heart-health benefits without a doubt. Or, rather, the benefits of a cocoa bean extract in pill form given to healthy, older volunteers. The COSMOS study was negative. Chocolate, or the cocoa bean extract they used, did not reduce cardiovascular events.

And yet for all the prepublication importance attached to COSMOS, it is scarcely mentioned. Had it been positive, rest assured that Mars, the candy bar company that cofunded the research, and other interested parties would have been shouting it from the rooftops. As it is, they’re already spinning it.

Which brings us to the multivitamin component. COSMOS actually had a 2 × 2 design. In other words, there were four groups in this study: chocolate plus multivitamin, chocolate plus placebo, placebo plus multivitamin, and placebo plus placebo. This type of study design allows you to study two different interventions simultaneously, provided that they are independent and do not interact with each other. In addition to the primary cardiovascular endpoint, they also studied a cancer endpoint.

The multivitamin supplement didn’t reduce cardiovascular events either. Nor did it affect cancer outcomes. The main COSMOS study was negative and reinforced what countless other studies have proven: Taking a daily multivitamin does not reduce your risk of having a heart attack or developing cancer.
 

But wait, there’s more: COSMOS-Mind

But no researcher worth his salt studies just one or two endpoints in a study. The participants also underwent neurologic and memory testing. These results were reported separately in the COSMOS-Mind study.

COSMOS-Mind is often described as a separate (or “new”) study. In reality, it included the same participants from the original COSMOS trial and measured yet another primary outcome of cognitive performance on a series of tests administered by telephone. Although there is nothing inherently wrong with studying multiple outcomes in your patient population (after all, that salami isn’t going to slice itself), they cannot all be primary outcomes. Some, by necessity, must be secondary hypothesis–generating outcomes. If you test enough endpoints, multiple hypothesis testing dictates that eventually you will get a positive result simply by chance.

There was a time when the neurocognitive outcomes of COSMOS would have been reported in the same paper as the cardiovascular outcomes, but that time seems to have passed us by. Researchers live or die by the number of their publications, and there is an inherent advantage to squeezing as many publications as possible from the same dataset. Though, to be fair, the journal would probably have asked them to split up the paper as well.

In brief, the cocoa extract again fell short in COSMOS-Mind, but the multivitamin arm did better on the composite cognitive outcome. It was a fairly small difference – a 0.07-point improvement on the z-score at the 3-year mark (the z-score is the mean divided by the standard deviation). Much was also made of the fact that the improvement seemed to vary by prior history of cardiovascular disease (CVD). Those with a history of CVD had a 0.11-point improvement, whereas those without had a 0.06-point improvement. The authors couldn’t offer a definitive explanation for these findings. Any argument that multivitamins improve cardiovascular health and therefore prevent vascular dementia has to contend with the fact that the main COSMOS study didn’t show a cardiovascular benefit for vitamins. Speculation that you are treating nutritional deficiencies is exactly that: speculation.

A more salient question is: What does a 0.07-point improvement on the z-score mean clinically? This study didn’t assess whether a multivitamin supplement prevented dementia or allowed people to live independently for longer. In fairness, that would have been exceptionally difficult to do and would have required a much longer study.

Their one attempt to quantify the cognitive benefit clinically was a calculation about normal age-related decline. Test scores were 0.045 points lower for every 1-year increase in age among participants (their mean age was 73 years). So the authors contend that a 0.07-point increase, or the 0.083-point increase that they found at year 3, corresponds to 1.8 years of age-related decline forestalled. Whether this is an appropriate assumption, I leave for the reader to decide.
 

COSMOS-Web and replication

The results of COSMOS-Mind were seemingly bolstered by the recent publication of COSMOS-Web. Although I’ve seen this study described as having replicated the results of COSMOS-Mind, that description is a bit misleading. This was yet another ancillary COSMOS study; more than half of the 2,262 participants in COSMOS-Mind were also included in COSMOS-Web. Replicating results in the same people isn’t true replication.

The main difference between COSMOS-Mind and COSMOS-Web is that the former used a telephone interview to administer the cognitive tests and the latter used the Internet. They also had different endpoints, with COSMOS-Web looking at immediate recall rather than a global test composite.

COSMOS-Web was a positive study in that patients getting the multivitamin supplement did better on the test for immediate memory recall (remembering a list of 20 words), though they didn’t improve on tests of memory retention, executive function, or novel object recognition (basically a test where subjects have to identify matching geometric patterns and then recall them later). They were able to remember an additional 0.71 word on average, compared with 0.44 word in the placebo group. (For the record, it found no benefit for the cocoa extract).

Everybody does better on memory tests the second time around because practice makes perfect, hence the improvement in the placebo group. This benefit at 1 year did not survive to the end of follow-up at 3 years, in contrast to COSMOS-Mind, where the benefit was not apparent at 1 year and seen only at year 3. A history of cardiovascular disease didn’t seem to affect the results in COSMOS-Web as it did in COSMOS-Mind. As far as replications go, COSMOS-Web has some very non-negligible differences, compared with COSMOS-Mind. This incongruity, especially given the overlap in the patient populations is hard to reconcile. If COSMOS-Web was supposed to assuage any doubts that persisted after COSMOS-Mind, it hasn’t for me.
 

One of these studies is not like the others

Finally, although the COSMOS trial and all its ancillary study analyses suggest a neurocognitive benefit to multivitamin supplementation, it’s not the first study to test the matter. The Age-Related Eye Disease Study looked at vitamin C, vitamin E, beta-carotene, zinc, and copper. There was no benefit on any of the six cognitive tests administered to patients. The Women’s Health Study, the Women’s Antioxidant Cardiovascular Study and PREADViSE have all failed to show any benefit to the various vitamins and minerals they studied. A meta-analysis of 11 trials found no benefit to B vitamins in slowing cognitive aging.

The claim that COSMOS is the “first” study to test the hypothesis hinges on some careful wordplay. Prior studies tested specific vitamins, not a multivitamin. In the discussion of the paper, these other studies are critiqued for being short term. But the Physicians’ Health Study II did in fact study a multivitamin and assessed cognitive performance on average 2.5 years after randomization. It found no benefit. The authors of COSMOS-Web critiqued the 2.5-year wait to perform cognitive testing, saying it would have missed any short-term benefits. Although, given that they simultaneously praised their 3 years of follow-up, the criticism is hard to fully accept or even understand.

Whether follow-up is short or long, uses individual vitamins or a multivitamin, the results excluding COSMOS are uniformly negative. I for one am skeptical that a multivitamin or any individual vitamin can prevent dementia. Same goes for chocolate.

Do enough tests in the same population, and something will rise above the noise just by chance. When you get a positive result in your research, it’s always exciting. But when a slew of studies that came before you are negative, you aren’t groundbreaking. You’re an outlier.

Dr. Labos is a cardiologist at Hôpital Notre-Dame, Montreal. He has disclosed no relevant financial relationships.

A version of this article appeared on Medscape.com.

I have written before about the COSMOS study and its finding that multivitamins (and chocolate) did not improve brain or cardiovascular health. So I was surprised to read that a “new” study found that vitamins can forestall dementia and age-related cognitive decline.

Upon closer look, the new data are neither new nor convincing, at least to me.

©Graça Victoria/iStockphoto.com

Chocolate and multivitamins for CVD and cancer prevention

The large randomized COSMOS trial was supposed to be the definitive study on chocolate that would establish its heart-health benefits without a doubt. Or, rather, the benefits of a cocoa bean extract in pill form given to healthy, older volunteers. The COSMOS study was negative. Chocolate, or the cocoa bean extract they used, did not reduce cardiovascular events.

And yet for all the prepublication importance attached to COSMOS, it is scarcely mentioned. Had it been positive, rest assured that Mars, the candy bar company that cofunded the research, and other interested parties would have been shouting it from the rooftops. As it is, they’re already spinning it.

Which brings us to the multivitamin component. COSMOS actually had a 2 × 2 design. In other words, there were four groups in this study: chocolate plus multivitamin, chocolate plus placebo, placebo plus multivitamin, and placebo plus placebo. This type of study design allows you to study two different interventions simultaneously, provided that they are independent and do not interact with each other. In addition to the primary cardiovascular endpoint, they also studied a cancer endpoint.

The multivitamin supplement didn’t reduce cardiovascular events either. Nor did it affect cancer outcomes. The main COSMOS study was negative and reinforced what countless other studies have proven: Taking a daily multivitamin does not reduce your risk of having a heart attack or developing cancer.
 

But wait, there’s more: COSMOS-Mind

But no researcher worth his salt studies just one or two endpoints in a study. The participants also underwent neurologic and memory testing. These results were reported separately in the COSMOS-Mind study.

COSMOS-Mind is often described as a separate (or “new”) study. In reality, it included the same participants from the original COSMOS trial and measured yet another primary outcome of cognitive performance on a series of tests administered by telephone. Although there is nothing inherently wrong with studying multiple outcomes in your patient population (after all, that salami isn’t going to slice itself), they cannot all be primary outcomes. Some, by necessity, must be secondary hypothesis–generating outcomes. If you test enough endpoints, multiple hypothesis testing dictates that eventually you will get a positive result simply by chance.

There was a time when the neurocognitive outcomes of COSMOS would have been reported in the same paper as the cardiovascular outcomes, but that time seems to have passed us by. Researchers live or die by the number of their publications, and there is an inherent advantage to squeezing as many publications as possible from the same dataset. Though, to be fair, the journal would probably have asked them to split up the paper as well.

In brief, the cocoa extract again fell short in COSMOS-Mind, but the multivitamin arm did better on the composite cognitive outcome. It was a fairly small difference – a 0.07-point improvement on the z-score at the 3-year mark (the z-score is the mean divided by the standard deviation). Much was also made of the fact that the improvement seemed to vary by prior history of cardiovascular disease (CVD). Those with a history of CVD had a 0.11-point improvement, whereas those without had a 0.06-point improvement. The authors couldn’t offer a definitive explanation for these findings. Any argument that multivitamins improve cardiovascular health and therefore prevent vascular dementia has to contend with the fact that the main COSMOS study didn’t show a cardiovascular benefit for vitamins. Speculation that you are treating nutritional deficiencies is exactly that: speculation.

A more salient question is: What does a 0.07-point improvement on the z-score mean clinically? This study didn’t assess whether a multivitamin supplement prevented dementia or allowed people to live independently for longer. In fairness, that would have been exceptionally difficult to do and would have required a much longer study.

Their one attempt to quantify the cognitive benefit clinically was a calculation about normal age-related decline. Test scores were 0.045 points lower for every 1-year increase in age among participants (their mean age was 73 years). So the authors contend that a 0.07-point increase, or the 0.083-point increase that they found at year 3, corresponds to 1.8 years of age-related decline forestalled. Whether this is an appropriate assumption, I leave for the reader to decide.
 

COSMOS-Web and replication

The results of COSMOS-Mind were seemingly bolstered by the recent publication of COSMOS-Web. Although I’ve seen this study described as having replicated the results of COSMOS-Mind, that description is a bit misleading. This was yet another ancillary COSMOS study; more than half of the 2,262 participants in COSMOS-Mind were also included in COSMOS-Web. Replicating results in the same people isn’t true replication.

The main difference between COSMOS-Mind and COSMOS-Web is that the former used a telephone interview to administer the cognitive tests and the latter used the Internet. They also had different endpoints, with COSMOS-Web looking at immediate recall rather than a global test composite.

COSMOS-Web was a positive study in that patients getting the multivitamin supplement did better on the test for immediate memory recall (remembering a list of 20 words), though they didn’t improve on tests of memory retention, executive function, or novel object recognition (basically a test where subjects have to identify matching geometric patterns and then recall them later). They were able to remember an additional 0.71 word on average, compared with 0.44 word in the placebo group. (For the record, it found no benefit for the cocoa extract).

Everybody does better on memory tests the second time around because practice makes perfect, hence the improvement in the placebo group. This benefit at 1 year did not survive to the end of follow-up at 3 years, in contrast to COSMOS-Mind, where the benefit was not apparent at 1 year and seen only at year 3. A history of cardiovascular disease didn’t seem to affect the results in COSMOS-Web as it did in COSMOS-Mind. As far as replications go, COSMOS-Web has some very non-negligible differences, compared with COSMOS-Mind. This incongruity, especially given the overlap in the patient populations is hard to reconcile. If COSMOS-Web was supposed to assuage any doubts that persisted after COSMOS-Mind, it hasn’t for me.
 

One of these studies is not like the others

Finally, although the COSMOS trial and all its ancillary study analyses suggest a neurocognitive benefit to multivitamin supplementation, it’s not the first study to test the matter. The Age-Related Eye Disease Study looked at vitamin C, vitamin E, beta-carotene, zinc, and copper. There was no benefit on any of the six cognitive tests administered to patients. The Women’s Health Study, the Women’s Antioxidant Cardiovascular Study and PREADViSE have all failed to show any benefit to the various vitamins and minerals they studied. A meta-analysis of 11 trials found no benefit to B vitamins in slowing cognitive aging.

The claim that COSMOS is the “first” study to test the hypothesis hinges on some careful wordplay. Prior studies tested specific vitamins, not a multivitamin. In the discussion of the paper, these other studies are critiqued for being short term. But the Physicians’ Health Study II did in fact study a multivitamin and assessed cognitive performance on average 2.5 years after randomization. It found no benefit. The authors of COSMOS-Web critiqued the 2.5-year wait to perform cognitive testing, saying it would have missed any short-term benefits. Although, given that they simultaneously praised their 3 years of follow-up, the criticism is hard to fully accept or even understand.

Whether follow-up is short or long, uses individual vitamins or a multivitamin, the results excluding COSMOS are uniformly negative. I for one am skeptical that a multivitamin or any individual vitamin can prevent dementia. Same goes for chocolate.

Do enough tests in the same population, and something will rise above the noise just by chance. When you get a positive result in your research, it’s always exciting. But when a slew of studies that came before you are negative, you aren’t groundbreaking. You’re an outlier.

Dr. Labos is a cardiologist at Hôpital Notre-Dame, Montreal. He has disclosed no relevant financial relationships.

A version of this article appeared on Medscape.com.

I have written before about the COSMOS study and its finding that multivitamins (and chocolate) did not improve brain or cardiovascular health. So I was surprised to read that a “new” study found that vitamins can forestall dementia and age-related cognitive decline.

Upon closer look, the new data are neither new nor convincing, at least to me.

©Graça Victoria/iStockphoto.com

Chocolate and multivitamins for CVD and cancer prevention

The large randomized COSMOS trial was supposed to be the definitive study on chocolate that would establish its heart-health benefits without a doubt. Or, rather, the benefits of a cocoa bean extract in pill form given to healthy, older volunteers. The COSMOS study was negative. Chocolate, or the cocoa bean extract they used, did not reduce cardiovascular events.

And yet for all the prepublication importance attached to COSMOS, it is scarcely mentioned. Had it been positive, rest assured that Mars, the candy bar company that cofunded the research, and other interested parties would have been shouting it from the rooftops. As it is, they’re already spinning it.

Which brings us to the multivitamin component. COSMOS actually had a 2 × 2 design. In other words, there were four groups in this study: chocolate plus multivitamin, chocolate plus placebo, placebo plus multivitamin, and placebo plus placebo. This type of study design allows you to study two different interventions simultaneously, provided that they are independent and do not interact with each other. In addition to the primary cardiovascular endpoint, they also studied a cancer endpoint.

The multivitamin supplement didn’t reduce cardiovascular events either. Nor did it affect cancer outcomes. The main COSMOS study was negative and reinforced what countless other studies have proven: Taking a daily multivitamin does not reduce your risk of having a heart attack or developing cancer.
 

But wait, there’s more: COSMOS-Mind

But no researcher worth his salt studies just one or two endpoints in a study. The participants also underwent neurologic and memory testing. These results were reported separately in the COSMOS-Mind study.

COSMOS-Mind is often described as a separate (or “new”) study. In reality, it included the same participants from the original COSMOS trial and measured yet another primary outcome of cognitive performance on a series of tests administered by telephone. Although there is nothing inherently wrong with studying multiple outcomes in your patient population (after all, that salami isn’t going to slice itself), they cannot all be primary outcomes. Some, by necessity, must be secondary hypothesis–generating outcomes. If you test enough endpoints, multiple hypothesis testing dictates that eventually you will get a positive result simply by chance.

There was a time when the neurocognitive outcomes of COSMOS would have been reported in the same paper as the cardiovascular outcomes, but that time seems to have passed us by. Researchers live or die by the number of their publications, and there is an inherent advantage to squeezing as many publications as possible from the same dataset. Though, to be fair, the journal would probably have asked them to split up the paper as well.

In brief, the cocoa extract again fell short in COSMOS-Mind, but the multivitamin arm did better on the composite cognitive outcome. It was a fairly small difference – a 0.07-point improvement on the z-score at the 3-year mark (the z-score is the mean divided by the standard deviation). Much was also made of the fact that the improvement seemed to vary by prior history of cardiovascular disease (CVD). Those with a history of CVD had a 0.11-point improvement, whereas those without had a 0.06-point improvement. The authors couldn’t offer a definitive explanation for these findings. Any argument that multivitamins improve cardiovascular health and therefore prevent vascular dementia has to contend with the fact that the main COSMOS study didn’t show a cardiovascular benefit for vitamins. Speculation that you are treating nutritional deficiencies is exactly that: speculation.

A more salient question is: What does a 0.07-point improvement on the z-score mean clinically? This study didn’t assess whether a multivitamin supplement prevented dementia or allowed people to live independently for longer. In fairness, that would have been exceptionally difficult to do and would have required a much longer study.

Their one attempt to quantify the cognitive benefit clinically was a calculation about normal age-related decline. Test scores were 0.045 points lower for every 1-year increase in age among participants (their mean age was 73 years). So the authors contend that a 0.07-point increase, or the 0.083-point increase that they found at year 3, corresponds to 1.8 years of age-related decline forestalled. Whether this is an appropriate assumption, I leave for the reader to decide.
 

COSMOS-Web and replication

The results of COSMOS-Mind were seemingly bolstered by the recent publication of COSMOS-Web. Although I’ve seen this study described as having replicated the results of COSMOS-Mind, that description is a bit misleading. This was yet another ancillary COSMOS study; more than half of the 2,262 participants in COSMOS-Mind were also included in COSMOS-Web. Replicating results in the same people isn’t true replication.

The main difference between COSMOS-Mind and COSMOS-Web is that the former used a telephone interview to administer the cognitive tests and the latter used the Internet. They also had different endpoints, with COSMOS-Web looking at immediate recall rather than a global test composite.

COSMOS-Web was a positive study in that patients getting the multivitamin supplement did better on the test for immediate memory recall (remembering a list of 20 words), though they didn’t improve on tests of memory retention, executive function, or novel object recognition (basically a test where subjects have to identify matching geometric patterns and then recall them later). They were able to remember an additional 0.71 word on average, compared with 0.44 word in the placebo group. (For the record, it found no benefit for the cocoa extract).

Everybody does better on memory tests the second time around because practice makes perfect, hence the improvement in the placebo group. This benefit at 1 year did not survive to the end of follow-up at 3 years, in contrast to COSMOS-Mind, where the benefit was not apparent at 1 year and seen only at year 3. A history of cardiovascular disease didn’t seem to affect the results in COSMOS-Web as it did in COSMOS-Mind. As far as replications go, COSMOS-Web has some very non-negligible differences, compared with COSMOS-Mind. This incongruity, especially given the overlap in the patient populations is hard to reconcile. If COSMOS-Web was supposed to assuage any doubts that persisted after COSMOS-Mind, it hasn’t for me.
 

One of these studies is not like the others

Finally, although the COSMOS trial and all its ancillary study analyses suggest a neurocognitive benefit to multivitamin supplementation, it’s not the first study to test the matter. The Age-Related Eye Disease Study looked at vitamin C, vitamin E, beta-carotene, zinc, and copper. There was no benefit on any of the six cognitive tests administered to patients. The Women’s Health Study, the Women’s Antioxidant Cardiovascular Study and PREADViSE have all failed to show any benefit to the various vitamins and minerals they studied. A meta-analysis of 11 trials found no benefit to B vitamins in slowing cognitive aging.

The claim that COSMOS is the “first” study to test the hypothesis hinges on some careful wordplay. Prior studies tested specific vitamins, not a multivitamin. In the discussion of the paper, these other studies are critiqued for being short term. But the Physicians’ Health Study II did in fact study a multivitamin and assessed cognitive performance on average 2.5 years after randomization. It found no benefit. The authors of COSMOS-Web critiqued the 2.5-year wait to perform cognitive testing, saying it would have missed any short-term benefits. Although, given that they simultaneously praised their 3 years of follow-up, the criticism is hard to fully accept or even understand.

Whether follow-up is short or long, uses individual vitamins or a multivitamin, the results excluding COSMOS are uniformly negative. I for one am skeptical that a multivitamin or any individual vitamin can prevent dementia. Same goes for chocolate.

Do enough tests in the same population, and something will rise above the noise just by chance. When you get a positive result in your research, it’s always exciting. But when a slew of studies that came before you are negative, you aren’t groundbreaking. You’re an outlier.

Dr. Labos is a cardiologist at Hôpital Notre-Dame, Montreal. He has disclosed no relevant financial relationships.

A version of this article appeared on Medscape.com.

Given the patient's insidious cognitive decline, as well as increased agitation, irritability, anxiety, social isolation, inability to fully manage finances, loss of routine hygienic practices, and loss of interest in regular meals, this patient is diagnosed with probable Alzheimer's disease (AD) dementia and is referred to a specialist for further testing.

AD is one of the most common forms of dementia. More than 6 million people in the United States have clinical AD or mild cognitive impairment because of AD. By 2060, the incidence of AD is expected to grow to 15 million people. AD is classified into four stages: preclinical, mild, moderate, and severe. Patients with preclinical AD — a relatively new classification currently only used for research — do not yet show abnormal results on physical exam or mental status testing, but areas of the brain are undergoing pathologic changes. Mild AD signs and symptoms include memory loss, compromised judgment, trouble handling money and paying bills, mood and personality changes, and increased anxiety. People with moderate AD show increasing signs of memory loss and confusion, problems with recognizing family and friends, and difficulty with organizing thoughts and thinking logically, and they repeat themselves in conversation, among other symptoms. Severe AD is generally described as a complete loss of self, with the inability to recognize family and friends, inability to communicate effectively, and complete dependence on others for care. 

Diagnosing AD currently relies on a clinical approach. A complete physical examination, with a detailed neurologic examination and a mental status examination, is used to evaluate disease stage and rule out comorbid conditions. Initial mental status testing should evaluate attention and concentration, recent and remote memory, language, praxis, executive function, and visuospatial function. Imaging studies may be performed to rule out other treatable causes of cognitive decline. In addition, volumetric studies of the hippocampus and 2-[¹⁸F]fluoro-2-deoxy-D-glucose PET with or without amyloid imaging can be used for early detection and differentiating dementia etiologies. Lumbar puncture as a diagnostic measure for levels of tau (which is often elevated in AD) and amyloid (which is often reduced in AD) is currently reserved for research settings.

Although the cause of AD is unknown, experts believe that environmental and genetic risk factors trigger a pathophysiologic cascade that, over decades, leads to Alzheimer's pathology and dementia. Universally accepted pathologic hallmarks of AD are beta-amyloid plaques and neurofibrillary tangles (NFTs). NFTs result from changes in the tau protein, a key chemical in neuronal support structures, and are associated with malfunctions in communication between neurons as well as cell death. Beta-amyloid plaques are dense, mostly insoluble deposits that develop around neurons in the hippocampus and other regions in the cerebral cortex used for decision-making, disrupting function and leading to brain atrophy. Risk factors for AD include advancing age, family history, APOE e4 genotype, insulin resistance, hypertension, depression, and traumatic brain injury.

After an AD diagnosis, physicians should encourage the involvement of family and friends who agree to become more involved in the patient's care as the disease progresses. These individuals need to understand the patient's wishes around care, especially for the future, when the patient is no longer able to make decisions. The patient may also consider establishing medical advance directives and durable power of attorney for medical and financial decision-making. Caregivers supporting the patient are encouraged to help balance the physical needs of the patient while maintaining respect for them as a competent adult to the extent allowed by the progression of their disease. 

Currently, AD treatments are focused on symptomatic therapies that modulate neurotransmitters — either acetylcholine or glutamate. The standard medical treatment includes cholinesterase inhibitors and a partial N-methyl-D-aspartate antagonist. Two amyloid-directed antibodies (aducanumab, lecanemab) are currently available in the US for individuals with AD exhibiting mild cognitive impairment or mild dementia. A third agent currently in clinical trials (donanemab) has shown significantly slowed clinical progression after 1.5 years among clinical trial participants with early symptomatic AD and amyloid and tau pathology.

Jasvinder Chawla, MD, Professor of Neurology, Loyola University Medical Center, Maywood; Director, Clinical Neurophysiology Lab, Department of Neurology, Hines VA Hospital, Hines, IL.

Jasvinder Chawla, MD, has disclosed no relevant financial relationships.

Image Quizzes are fictional or fictionalized clinical scenarios intended to provide evidence-based educational takeaways.

Given the patient's insidious cognitive decline, as well as increased agitation, irritability, anxiety, social isolation, inability to fully manage finances, loss of routine hygienic practices, and loss of interest in regular meals, this patient is diagnosed with probable Alzheimer's disease (AD) dementia and is referred to a specialist for further testing.

AD is one of the most common forms of dementia. More than 6 million people in the United States have clinical AD or mild cognitive impairment because of AD. By 2060, the incidence of AD is expected to grow to 15 million people. AD is classified into four stages: preclinical, mild, moderate, and severe. Patients with preclinical AD — a relatively new classification currently only used for research — do not yet show abnormal results on physical exam or mental status testing, but areas of the brain are undergoing pathologic changes. Mild AD signs and symptoms include memory loss, compromised judgment, trouble handling money and paying bills, mood and personality changes, and increased anxiety. People with moderate AD show increasing signs of memory loss and confusion, problems with recognizing family and friends, and difficulty with organizing thoughts and thinking logically, and they repeat themselves in conversation, among other symptoms. Severe AD is generally described as a complete loss of self, with the inability to recognize family and friends, inability to communicate effectively, and complete dependence on others for care. 

Diagnosing AD currently relies on a clinical approach. A complete physical examination, with a detailed neurologic examination and a mental status examination, is used to evaluate disease stage and rule out comorbid conditions. Initial mental status testing should evaluate attention and concentration, recent and remote memory, language, praxis, executive function, and visuospatial function. Imaging studies may be performed to rule out other treatable causes of cognitive decline. In addition, volumetric studies of the hippocampus and 2-[¹⁸F]fluoro-2-deoxy-D-glucose PET with or without amyloid imaging can be used for early detection and differentiating dementia etiologies. Lumbar puncture as a diagnostic measure for levels of tau (which is often elevated in AD) and amyloid (which is often reduced in AD) is currently reserved for research settings.

Although the cause of AD is unknown, experts believe that environmental and genetic risk factors trigger a pathophysiologic cascade that, over decades, leads to Alzheimer's pathology and dementia. Universally accepted pathologic hallmarks of AD are beta-amyloid plaques and neurofibrillary tangles (NFTs). NFTs result from changes in the tau protein, a key chemical in neuronal support structures, and are associated with malfunctions in communication between neurons as well as cell death. Beta-amyloid plaques are dense, mostly insoluble deposits that develop around neurons in the hippocampus and other regions in the cerebral cortex used for decision-making, disrupting function and leading to brain atrophy. Risk factors for AD include advancing age, family history, APOE e4 genotype, insulin resistance, hypertension, depression, and traumatic brain injury.

After an AD diagnosis, physicians should encourage the involvement of family and friends who agree to become more involved in the patient's care as the disease progresses. These individuals need to understand the patient's wishes around care, especially for the future, when the patient is no longer able to make decisions. The patient may also consider establishing medical advance directives and durable power of attorney for medical and financial decision-making. Caregivers supporting the patient are encouraged to help balance the physical needs of the patient while maintaining respect for them as a competent adult to the extent allowed by the progression of their disease. 

Currently, AD treatments are focused on symptomatic therapies that modulate neurotransmitters — either acetylcholine or glutamate. The standard medical treatment includes cholinesterase inhibitors and a partial N-methyl-D-aspartate antagonist. Two amyloid-directed antibodies (aducanumab, lecanemab) are currently available in the US for individuals with AD exhibiting mild cognitive impairment or mild dementia. A third agent currently in clinical trials (donanemab) has shown significantly slowed clinical progression after 1.5 years among clinical trial participants with early symptomatic AD and amyloid and tau pathology.

Jasvinder Chawla, MD, Professor of Neurology, Loyola University Medical Center, Maywood; Director, Clinical Neurophysiology Lab, Department of Neurology, Hines VA Hospital, Hines, IL.

Jasvinder Chawla, MD, has disclosed no relevant financial relationships.

Image Quizzes are fictional or fictionalized clinical scenarios intended to provide evidence-based educational takeaways.

Given the patient's insidious cognitive decline, as well as increased agitation, irritability, anxiety, social isolation, inability to fully manage finances, loss of routine hygienic practices, and loss of interest in regular meals, this patient is diagnosed with probable Alzheimer's disease (AD) dementia and is referred to a specialist for further testing.

AD is one of the most common forms of dementia. More than 6 million people in the United States have clinical AD or mild cognitive impairment because of AD. By 2060, the incidence of AD is expected to grow to 15 million people. AD is classified into four stages: preclinical, mild, moderate, and severe. Patients with preclinical AD — a relatively new classification currently only used for research — do not yet show abnormal results on physical exam or mental status testing, but areas of the brain are undergoing pathologic changes. Mild AD signs and symptoms include memory loss, compromised judgment, trouble handling money and paying bills, mood and personality changes, and increased anxiety. People with moderate AD show increasing signs of memory loss and confusion, problems with recognizing family and friends, and difficulty with organizing thoughts and thinking logically, and they repeat themselves in conversation, among other symptoms. Severe AD is generally described as a complete loss of self, with the inability to recognize family and friends, inability to communicate effectively, and complete dependence on others for care. 

Diagnosing AD currently relies on a clinical approach. A complete physical examination, with a detailed neurologic examination and a mental status examination, is used to evaluate disease stage and rule out comorbid conditions. Initial mental status testing should evaluate attention and concentration, recent and remote memory, language, praxis, executive function, and visuospatial function. Imaging studies may be performed to rule out other treatable causes of cognitive decline. In addition, volumetric studies of the hippocampus and 2-[¹⁸F]fluoro-2-deoxy-D-glucose PET with or without amyloid imaging can be used for early detection and differentiating dementia etiologies. Lumbar puncture as a diagnostic measure for levels of tau (which is often elevated in AD) and amyloid (which is often reduced in AD) is currently reserved for research settings.

Although the cause of AD is unknown, experts believe that environmental and genetic risk factors trigger a pathophysiologic cascade that, over decades, leads to Alzheimer's pathology and dementia. Universally accepted pathologic hallmarks of AD are beta-amyloid plaques and neurofibrillary tangles (NFTs). NFTs result from changes in the tau protein, a key chemical in neuronal support structures, and are associated with malfunctions in communication between neurons as well as cell death. Beta-amyloid plaques are dense, mostly insoluble deposits that develop around neurons in the hippocampus and other regions in the cerebral cortex used for decision-making, disrupting function and leading to brain atrophy. Risk factors for AD include advancing age, family history, APOE e4 genotype, insulin resistance, hypertension, depression, and traumatic brain injury.

After an AD diagnosis, physicians should encourage the involvement of family and friends who agree to become more involved in the patient's care as the disease progresses. These individuals need to understand the patient's wishes around care, especially for the future, when the patient is no longer able to make decisions. The patient may also consider establishing medical advance directives and durable power of attorney for medical and financial decision-making. Caregivers supporting the patient are encouraged to help balance the physical needs of the patient while maintaining respect for them as a competent adult to the extent allowed by the progression of their disease. 

Currently, AD treatments are focused on symptomatic therapies that modulate neurotransmitters — either acetylcholine or glutamate. The standard medical treatment includes cholinesterase inhibitors and a partial N-methyl-D-aspartate antagonist. Two amyloid-directed antibodies (aducanumab, lecanemab) are currently available in the US for individuals with AD exhibiting mild cognitive impairment or mild dementia. A third agent currently in clinical trials (donanemab) has shown significantly slowed clinical progression after 1.5 years among clinical trial participants with early symptomatic AD and amyloid and tau pathology.

Jasvinder Chawla, MD, Professor of Neurology, Loyola University Medical Center, Maywood; Director, Clinical Neurophysiology Lab, Department of Neurology, Hines VA Hospital, Hines, IL.

Jasvinder Chawla, MD, has disclosed no relevant financial relationships.

Image Quizzes are fictional or fictionalized clinical scenarios intended to provide evidence-based educational takeaways.

Traumatic brain injury (TBI) that occurs in early adulthood is associated with cognitive decline in later life, results from a study of identical twins who served in World War II show.

The research, which included almost 9,000 individuals, showed that twins who had experienced a TBI were more likely to have lower cognitive function at age 70 versus their twin who did not experience a TBI, especially if they had lost consciousness or were older than age 24 at the time of injury. In addition, their cognitive decline occurred at a more rapid rate.

“We know that TBI increases the risk of developing Alzheimer’s disease and other dementias in later life, but we haven’t known about TBI’s effect on cognitive decline that does not quite meet the threshold for dementia,” study investigator Marianne Chanti-Ketterl, PhD, Duke University, Durham, N.C., said in an interview.

“We know that TBI increases the risk of dementia in later life, but we haven’t known if TBI affects cognitive function, causes cognitive decline that has not progressed to the point of severity with Alzheimer’s or dementia,” she added.

Being able to study the impact of TBI in monozygotic twins gives this study a unique strength, she noted.

“The important thing about this is that they are monozygotic twins, and we know they shared a lot of early life exposure, and almost 100% genetics,” Dr. Chanti-Ketterl said.

The study was published online in Neurology.

For the study, the investigators assessed 8,662 participants born between 1917 and 1927 who were part of the National Academy of Sciences National Research Council’s Twin Registry. The registry is composed of male veterans of World War II with a history of TBI, as reported by themselves or a caregiver.

The men were followed up for many years as part of the registry, but cognitive assessment only began in the 1990s. They were followed up at four different time points, at which time the Telephone Interview for Cognitive Status (TICS-m), an alternative to the Mini-Mental State Examination that must be given in person, was administered.

A total of 25% of participants had experienced concussion in their lifetime. Of this cohort, there were 589 pairs of monozygotic twins who were discordant (one twin had TBI and the other had not).

Among the monozygotic twin cohort, a history of any TBI and being older than age 24 at the time of TBI were associated with lower TICS-m scores.

A twin who experienced TBI after age 24 scored 0.59 points lower on the TICS-m at age 70 than his twin with no TBI, and cognitive function declined faster, by 0.05 points per year.
 

First study of its kind

Holly Elser, MD, PhD, MPH, an epidemiologist and resident physician in neurology at the University of Pennsylvania, Philadelphia, and coauthor of an accompanying editorial, said in an interview that the study’s twin design was a definite strength.

“There are lots of papers that have remarked on the apparent association between head injury and subsequent dementia or cognitive decline, but to my knowledge, this is one of the first, if not the first, to use a twin study design, which has the unique advantage of having better control over early life and genetic factors than would ever typically be possible in a dataset of unrelated adults,” said Dr. Elser.

She added that the study findings “strengthen our understanding of the relationship between TBI and later cognitive decline, so I think there is an etiologic value to the study.”

However, Dr. Elser noted that the composition of the study population may limit the extent to which the results apply to contemporary populations.

“This was a population of White male twins born between 1917 and 1927,” she noted. “However, does the experience of people who were in the military generalize to civilian populations? Are twins representative of the general population or are they unique in terms of their risk factors?”

It is always important to emphasize inclusivity in clinical research, and in dementia research in particular, Dr. Elser added.

“There are many examples of instances where racialized and otherwise economically marginalized groups have been excluded from analysis, which is problematic because there are already economically and socially marginalized groups who disproportionately bear the brunt of dementia.

“This is not a criticism of the authors’ work, that their data didn’t include a more diverse patient base, but I think it is an important reminder that we should always interpret study findings within the limitations of the data. It’s a reminder to be thoughtful about taking explicit steps to include more diverse groups in future research,” she said.

The study was funded by the National Institute on Aging/National Institutes of Health and the Department of Defense. Dr. Chanti-Ketterl and Dr. Elser have reported no relevant financial relationships.

A version of this article appeared on Medscape.com.

Traumatic brain injury (TBI) that occurs in early adulthood is associated with cognitive decline in later life, results from a study of identical twins who served in World War II show.

The research, which included almost 9,000 individuals, showed that twins who had experienced a TBI were more likely to have lower cognitive function at age 70 versus their twin who did not experience a TBI, especially if they had lost consciousness or were older than age 24 at the time of injury. In addition, their cognitive decline occurred at a more rapid rate.

“We know that TBI increases the risk of developing Alzheimer’s disease and other dementias in later life, but we haven’t known about TBI’s effect on cognitive decline that does not quite meet the threshold for dementia,” study investigator Marianne Chanti-Ketterl, PhD, Duke University, Durham, N.C., said in an interview.

“We know that TBI increases the risk of dementia in later life, but we haven’t known if TBI affects cognitive function, causes cognitive decline that has not progressed to the point of severity with Alzheimer’s or dementia,” she added.

Being able to study the impact of TBI in monozygotic twins gives this study a unique strength, she noted.

“The important thing about this is that they are monozygotic twins, and we know they shared a lot of early life exposure, and almost 100% genetics,” Dr. Chanti-Ketterl said.

The study was published online in Neurology.

For the study, the investigators assessed 8,662 participants born between 1917 and 1927 who were part of the National Academy of Sciences National Research Council’s Twin Registry. The registry is composed of male veterans of World War II with a history of TBI, as reported by themselves or a caregiver.

The men were followed up for many years as part of the registry, but cognitive assessment only began in the 1990s. They were followed up at four different time points, at which time the Telephone Interview for Cognitive Status (TICS-m), an alternative to the Mini-Mental State Examination that must be given in person, was administered.

A total of 25% of participants had experienced concussion in their lifetime. Of this cohort, there were 589 pairs of monozygotic twins who were discordant (one twin had TBI and the other had not).

Among the monozygotic twin cohort, a history of any TBI and being older than age 24 at the time of TBI were associated with lower TICS-m scores.

A twin who experienced TBI after age 24 scored 0.59 points lower on the TICS-m at age 70 than his twin with no TBI, and cognitive function declined faster, by 0.05 points per year.
 

First study of its kind

Holly Elser, MD, PhD, MPH, an epidemiologist and resident physician in neurology at the University of Pennsylvania, Philadelphia, and coauthor of an accompanying editorial, said in an interview that the study’s twin design was a definite strength.

“There are lots of papers that have remarked on the apparent association between head injury and subsequent dementia or cognitive decline, but to my knowledge, this is one of the first, if not the first, to use a twin study design, which has the unique advantage of having better control over early life and genetic factors than would ever typically be possible in a dataset of unrelated adults,” said Dr. Elser.

She added that the study findings “strengthen our understanding of the relationship between TBI and later cognitive decline, so I think there is an etiologic value to the study.”

However, Dr. Elser noted that the composition of the study population may limit the extent to which the results apply to contemporary populations.

“This was a population of White male twins born between 1917 and 1927,” she noted. “However, does the experience of people who were in the military generalize to civilian populations? Are twins representative of the general population or are they unique in terms of their risk factors?”

It is always important to emphasize inclusivity in clinical research, and in dementia research in particular, Dr. Elser added.

“There are many examples of instances where racialized and otherwise economically marginalized groups have been excluded from analysis, which is problematic because there are already economically and socially marginalized groups who disproportionately bear the brunt of dementia.

“This is not a criticism of the authors’ work, that their data didn’t include a more diverse patient base, but I think it is an important reminder that we should always interpret study findings within the limitations of the data. It’s a reminder to be thoughtful about taking explicit steps to include more diverse groups in future research,” she said.

The study was funded by the National Institute on Aging/National Institutes of Health and the Department of Defense. Dr. Chanti-Ketterl and Dr. Elser have reported no relevant financial relationships.

A version of this article appeared on Medscape.com.

Traumatic brain injury (TBI) that occurs in early adulthood is associated with cognitive decline in later life, results from a study of identical twins who served in World War II show.

The research, which included almost 9,000 individuals, showed that twins who had experienced a TBI were more likely to have lower cognitive function at age 70 versus their twin who did not experience a TBI, especially if they had lost consciousness or were older than age 24 at the time of injury. In addition, their cognitive decline occurred at a more rapid rate.

“We know that TBI increases the risk of developing Alzheimer’s disease and other dementias in later life, but we haven’t known about TBI’s effect on cognitive decline that does not quite meet the threshold for dementia,” study investigator Marianne Chanti-Ketterl, PhD, Duke University, Durham, N.C., said in an interview.

“We know that TBI increases the risk of dementia in later life, but we haven’t known if TBI affects cognitive function, causes cognitive decline that has not progressed to the point of severity with Alzheimer’s or dementia,” she added.

Being able to study the impact of TBI in monozygotic twins gives this study a unique strength, she noted.

“The important thing about this is that they are monozygotic twins, and we know they shared a lot of early life exposure, and almost 100% genetics,” Dr. Chanti-Ketterl said.

The study was published online in Neurology.

For the study, the investigators assessed 8,662 participants born between 1917 and 1927 who were part of the National Academy of Sciences National Research Council’s Twin Registry. The registry is composed of male veterans of World War II with a history of TBI, as reported by themselves or a caregiver.

The men were followed up for many years as part of the registry, but cognitive assessment only began in the 1990s. They were followed up at four different time points, at which time the Telephone Interview for Cognitive Status (TICS-m), an alternative to the Mini-Mental State Examination that must be given in person, was administered.

A total of 25% of participants had experienced concussion in their lifetime. Of this cohort, there were 589 pairs of monozygotic twins who were discordant (one twin had TBI and the other had not).

Among the monozygotic twin cohort, a history of any TBI and being older than age 24 at the time of TBI were associated with lower TICS-m scores.

A twin who experienced TBI after age 24 scored 0.59 points lower on the TICS-m at age 70 than his twin with no TBI, and cognitive function declined faster, by 0.05 points per year.
 

First study of its kind

Holly Elser, MD, PhD, MPH, an epidemiologist and resident physician in neurology at the University of Pennsylvania, Philadelphia, and coauthor of an accompanying editorial, said in an interview that the study’s twin design was a definite strength.

“There are lots of papers that have remarked on the apparent association between head injury and subsequent dementia or cognitive decline, but to my knowledge, this is one of the first, if not the first, to use a twin study design, which has the unique advantage of having better control over early life and genetic factors than would ever typically be possible in a dataset of unrelated adults,” said Dr. Elser.

She added that the study findings “strengthen our understanding of the relationship between TBI and later cognitive decline, so I think there is an etiologic value to the study.”

However, Dr. Elser noted that the composition of the study population may limit the extent to which the results apply to contemporary populations.

“This was a population of White male twins born between 1917 and 1927,” she noted. “However, does the experience of people who were in the military generalize to civilian populations? Are twins representative of the general population or are they unique in terms of their risk factors?”

It is always important to emphasize inclusivity in clinical research, and in dementia research in particular, Dr. Elser added.

“There are many examples of instances where racialized and otherwise economically marginalized groups have been excluded from analysis, which is problematic because there are already economically and socially marginalized groups who disproportionately bear the brunt of dementia.

“This is not a criticism of the authors’ work, that their data didn’t include a more diverse patient base, but I think it is an important reminder that we should always interpret study findings within the limitations of the data. It’s a reminder to be thoughtful about taking explicit steps to include more diverse groups in future research,” she said.

The study was funded by the National Institute on Aging/National Institutes of Health and the Department of Defense. Dr. Chanti-Ketterl and Dr. Elser have reported no relevant financial relationships.

A version of this article appeared on Medscape.com.

A newly published scientific statement from the American Heart Association focuses on the impact of aggressive low-density lipoprotein cholesterol (LDL-C) lowering on the risk for dementia and hemorrhagic stroke.

“The brain is the body’s most cholesterol-rich organ, and some have questioned whether aggressive LDL-C lowering induces abnormal structural and functional changes,” the writing group, led by Larry Goldstein, MD, chair, department of neurology, University of Kentucky, Lexington, points out.

The 39-page AHA scientific statement, titled “Aggressive LDL-C Lowering and the Brain: Impact on Risk for Dementia and Hemorrhagic Stroke,” was published online in the journal Arteriosclerosis, Thrombosis, and Vascular Biology.

The objective was to evaluate contemporary evidence that either supports or refutes the conclusion that aggressive LDL-C lowering or lipid lowering exerts toxic effects on the brain, leading to cognitive impairment or dementia or hemorrhagic stroke.

The eight-member writing group used literature reviews, references to published clinical and epidemiology studies, clinical and public health guidelines, authoritative statements, and expert opinion to summarize the latest evidence and identify gaps in current knowledge.

They reached four main conclusions:

• First, the available data “consistently” show that LDL-C lowering reduces the risk of atherosclerotic cardiovascular disease-related events in high-risk groups.
• Second, although some older retrospective, case-control, and prospective longitudinal studies suggest that statins and LDL-C lowering are associated with cognitive impairment or dementia, the “preponderance” of observational studies and data from randomized trials do not support this conclusion, at least among trials with median follow-up of up to 6 years. The group says additional studies are needed to ensure cognitive safety over longer periods of time. For now, contemporary guidelines recommending the risk-stratified attainment of lipid-lowering goals are “reasonable,” they conclude.
• Third, the risk for hemorrhagic stroke associated with statin therapy in patients without a history of cerebrovascular disease is “small and consistently nonsignificant.” They found no evidence that PCSK9 inhibitors or ezetimibe (Zetia) increases bleeding risk. Further, there is “no indication” that patients or populations with lifelong low LDL-C have enhanced vulnerability to hemorrhagic stroke, and there is “little evidence” that achieving very low levels of LDL-C increases that risk. What is clear, the writing group says, is that lower LDL-C levels correlate with lower risk of overall stroke and stroke recurrence, mostly related to a reduction in ischemic stroke. “Concern about hemorrhagic stroke risk should not deter a clinician from treating LDL-C to guideline-recommended risk-stratified targets,” the writing group says.
• Fourth, the group notes that data reflecting the risk of hemorrhagic stroke with statin therapy among patients with a history of hemorrhagic stroke are not robust. PCSK9 inhibitors have not been adequately tested in patients with prior intracerebral hemorrhage. Lipid lowering in these populations requires more focused study.

The research had no commercial funding. A list of disclosures for the writing group is available with the original article.

A version of this article appeared on Medscape.com.

A newly published scientific statement from the American Heart Association focuses on the impact of aggressive low-density lipoprotein cholesterol (LDL-C) lowering on the risk for dementia and hemorrhagic stroke.

“The brain is the body’s most cholesterol-rich organ, and some have questioned whether aggressive LDL-C lowering induces abnormal structural and functional changes,” the writing group, led by Larry Goldstein, MD, chair, department of neurology, University of Kentucky, Lexington, points out.

The 39-page AHA scientific statement, titled “Aggressive LDL-C Lowering and the Brain: Impact on Risk for Dementia and Hemorrhagic Stroke,” was published online in the journal Arteriosclerosis, Thrombosis, and Vascular Biology.

The objective was to evaluate contemporary evidence that either supports or refutes the conclusion that aggressive LDL-C lowering or lipid lowering exerts toxic effects on the brain, leading to cognitive impairment or dementia or hemorrhagic stroke.

The eight-member writing group used literature reviews, references to published clinical and epidemiology studies, clinical and public health guidelines, authoritative statements, and expert opinion to summarize the latest evidence and identify gaps in current knowledge.

They reached four main conclusions:

• First, the available data “consistently” show that LDL-C lowering reduces the risk of atherosclerotic cardiovascular disease-related events in high-risk groups.
• Second, although some older retrospective, case-control, and prospective longitudinal studies suggest that statins and LDL-C lowering are associated with cognitive impairment or dementia, the “preponderance” of observational studies and data from randomized trials do not support this conclusion, at least among trials with median follow-up of up to 6 years. The group says additional studies are needed to ensure cognitive safety over longer periods of time. For now, contemporary guidelines recommending the risk-stratified attainment of lipid-lowering goals are “reasonable,” they conclude.
• Third, the risk for hemorrhagic stroke associated with statin therapy in patients without a history of cerebrovascular disease is “small and consistently nonsignificant.” They found no evidence that PCSK9 inhibitors or ezetimibe (Zetia) increases bleeding risk. Further, there is “no indication” that patients or populations with lifelong low LDL-C have enhanced vulnerability to hemorrhagic stroke, and there is “little evidence” that achieving very low levels of LDL-C increases that risk. What is clear, the writing group says, is that lower LDL-C levels correlate with lower risk of overall stroke and stroke recurrence, mostly related to a reduction in ischemic stroke. “Concern about hemorrhagic stroke risk should not deter a clinician from treating LDL-C to guideline-recommended risk-stratified targets,” the writing group says.
• Fourth, the group notes that data reflecting the risk of hemorrhagic stroke with statin therapy among patients with a history of hemorrhagic stroke are not robust. PCSK9 inhibitors have not been adequately tested in patients with prior intracerebral hemorrhage. Lipid lowering in these populations requires more focused study.

The research had no commercial funding. A list of disclosures for the writing group is available with the original article.

A version of this article appeared on Medscape.com.

A newly published scientific statement from the American Heart Association focuses on the impact of aggressive low-density lipoprotein cholesterol (LDL-C) lowering on the risk for dementia and hemorrhagic stroke.

“The brain is the body’s most cholesterol-rich organ, and some have questioned whether aggressive LDL-C lowering induces abnormal structural and functional changes,” the writing group, led by Larry Goldstein, MD, chair, department of neurology, University of Kentucky, Lexington, points out.

The 39-page AHA scientific statement, titled “Aggressive LDL-C Lowering and the Brain: Impact on Risk for Dementia and Hemorrhagic Stroke,” was published online in the journal Arteriosclerosis, Thrombosis, and Vascular Biology.

The objective was to evaluate contemporary evidence that either supports or refutes the conclusion that aggressive LDL-C lowering or lipid lowering exerts toxic effects on the brain, leading to cognitive impairment or dementia or hemorrhagic stroke.

The eight-member writing group used literature reviews, references to published clinical and epidemiology studies, clinical and public health guidelines, authoritative statements, and expert opinion to summarize the latest evidence and identify gaps in current knowledge.

They reached four main conclusions:

• First, the available data “consistently” show that LDL-C lowering reduces the risk of atherosclerotic cardiovascular disease-related events in high-risk groups.
• Second, although some older retrospective, case-control, and prospective longitudinal studies suggest that statins and LDL-C lowering are associated with cognitive impairment or dementia, the “preponderance” of observational studies and data from randomized trials do not support this conclusion, at least among trials with median follow-up of up to 6 years. The group says additional studies are needed to ensure cognitive safety over longer periods of time. For now, contemporary guidelines recommending the risk-stratified attainment of lipid-lowering goals are “reasonable,” they conclude.
• Third, the risk for hemorrhagic stroke associated with statin therapy in patients without a history of cerebrovascular disease is “small and consistently nonsignificant.” They found no evidence that PCSK9 inhibitors or ezetimibe (Zetia) increases bleeding risk. Further, there is “no indication” that patients or populations with lifelong low LDL-C have enhanced vulnerability to hemorrhagic stroke, and there is “little evidence” that achieving very low levels of LDL-C increases that risk. What is clear, the writing group says, is that lower LDL-C levels correlate with lower risk of overall stroke and stroke recurrence, mostly related to a reduction in ischemic stroke. “Concern about hemorrhagic stroke risk should not deter a clinician from treating LDL-C to guideline-recommended risk-stratified targets,” the writing group says.
• Fourth, the group notes that data reflecting the risk of hemorrhagic stroke with statin therapy among patients with a history of hemorrhagic stroke are not robust. PCSK9 inhibitors have not been adequately tested in patients with prior intracerebral hemorrhage. Lipid lowering in these populations requires more focused study.

The research had no commercial funding. A list of disclosures for the writing group is available with the original article.

A version of this article appeared on Medscape.com.

Lecanemab (Lequembi, Esai), an amyloid-beta–directed antibody therapy, is approved by the Food and Drug Administration for the treatment of Alzheimer’s disease (AD). But exactly how the drug clears amyloid-beta wasn’t clear.

Now new research suggests the drug, which was approved by the FDA in January, targets a particular molecular cascade, the plasma contact system, which drives amyloid-beta toxicity.

The investigators tested the effectiveness of various forms of amyloid-beta in activating the plasma contact system and found that amyloid-beta protofibrils, known to be the most toxic form of amyloid-beta, promoted the activation of this molecular cascade and that lecanemab inhibited pathway activation.

“In our study, we looked at lecanemab and found it can block the activation of the contact system, which could be one of the reasons that it works so well for AD,” study coinvestigator Erin Norris, PhD, research associate professor, Rockefeller University, New York, said in an interview.

The study was published online in the Proceedings of the National Academy of Science.
 

Unknown mechanism

“Many years ago, we started looking at the involvement of vascular dysfunction in AD,” Dr. Norris said. “We wanted to see whether or not irregular blood clotting or problems with blood flow was problematic in Alzheimer’s patients.”

The researchers found that fibrin, a major component involved in blood clotting, can extravasate into the brain.

“The blood-brain barrier can break down in Alzheimer’s, so things from the blood can move into the brain and deposit there,” she added. Fibrin then interacts with amyloid-beta, the major pathogenic protein in AD.

Dr. Norris explained that fibrin clots can form in two different ways. One is through the normal process that occurs when there’s an injury and bleeding. The second is through intrinsic clotting, which takes place through the contact system.

“We started looking into this system and found that the plasma of Alzheimer’s patients showed irregular levels of these enzymes and proteins that are part of the intrinsic clotting system compared to those of normal controls,” said Dr. Norris.

“This paper was an extension of years studying this pathway and these mechanisms. It was also inspired by the approval of lecanemab and its release for use in Alzheimer’s patients,” she added.

In previous research, the same researchers found that amyloid-beta has different forms. “It’s normally soluble, and it’s a very tiny molecule,” Dr. Norris said. “But over time, and in different situations, it can start to aggregate, becoming bigger and bigger.”
 

Implications beyond Alzheimer’s

Postmortem tissue analysis has found fibrillar plaques that are “clumped together.” These are insoluble and hard to get rid of, she said. “Protofibrils are the step before amyloid-beta forms fibrils and are considered to be the most toxic form, although the mechanism behind why it’s so toxic is not understood.”

Previous research has already shown that amyloid-beta can activate the contact system. The contact system has two “arms,” the first of which is involved with clotting, and the second with inflammation, Dr. Norris said. In fact, it’s the plasma contact system that links vascular and inflammatory pathways.

The plasma contact system leads to the clotting of fibrin, Dr. Norris continued. It activates factor XII, which leads to blood clotting by binding to coagulation factor XI.

The contact system also causes inflammation – the second “arm.” Bradykinin, a potent inflammatory molecule, is released by binding to high-molecular-weight kininogen (HK). In addition to inflammation, bradykinin can cause edema and blood-brain barrier permeability.

Although it’s been known that amyloid-beta can activate the contact system, the particular form of amyloid-beta implicated in this cascade has not been identified. And so, the researchers incubated amyloid-beta42 with human plasma, testing various types of amyloid-beta – monomers, oligomers, protofibrils, and fibrils – to see which would activate the contact system.

Amyloid-beta protofibrils promoted the activation of the contact system, as evidenced by several reactions, including activation of factor XII, while other forms of amyloid-beta did not. HK also “bound tightly” to amyloid-beta protofibrils, with “weaker” binding to other amyloid-beta species, the authors reported, confirming that amyloid-beta protofibrils bind to HK and factor XII.

Bradykinin levels were increased by amyloid-beta protofibrils, which also induced faster clotting, compared with other forms of amyloid-beta.

The researchers introduced lecanemab into the picture and found it “dramatically inhibited” contact system activation induced by amyloid-beta protofibrils. For example, it blocked the binding of factor XII to amyloid-beta. By contrast, human IgG (which the researchers used as a control) had no effect.

Additionally, lecanemab also prevented accelerated intrinsic coagulation in normal human plasma mediated by amyloid-beta protofibril.

Senior author Sidney Strickland, PhD, the Zachary and Elizabeth M. Fisher professor in Alzheimer’s and neurodegenerative disease, Rockefeller University, said in an interview: “One of the strong motivators for conducting this study was the fact that this drug, which is effective in AD, targets this specific form of amyloid-beta; but no one knows why it›s more toxic. We thought we could see if we could tie it to what we›re working on, and we found it ties in beautifully.”

The findings have implications that go beyond AD, Dr. Strickland said. “The contact system is implicated in lots of different pathologies, including sickle cell anemia, sepsis, inflammatory bowel disease, and so on.” Blocking the contact system might be a helpful approach in these conditions too.
 

Innovative, plausible, but still preliminary

In a comment, Heather M. Snyder, PhD, vice president of medical and scientific relations at the Alzheimer’s Association, called the investigation “innovative,” with ideas that are “certainly plausible.” However, “at this time, the work is preliminary and not conclusive.”

The hypothesized mechanisms for why amyloid (lecanemab’s target) is toxic to the brain “does incorporate important AD-related brain changes that have been observed in other studies, including inflammatory/immune changes and vascular-related changes,” said Dr. Snyder, who was not involved with the current study.

However, “additional studies that look both in model systems and in humans are needed to further illuminate these relationships,” Dr. Snyder said.

The study was supported by grants from the National Institutes of Health as well as the Robertson Therapeutic Development Fund, Samuel Newhouse Foundation, John A. Herrmann, and the May and Samuel Rudin Family Foundation. Dr. Norris, Dr. Strickland, and Dr. Snyder declared no relevant financial relationships.

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

Lecanemab (Lequembi, Esai), an amyloid-beta–directed antibody therapy, is approved by the Food and Drug Administration for the treatment of Alzheimer’s disease (AD). But exactly how the drug clears amyloid-beta wasn’t clear.

Now new research suggests the drug, which was approved by the FDA in January, targets a particular molecular cascade, the plasma contact system, which drives amyloid-beta toxicity.

The investigators tested the effectiveness of various forms of amyloid-beta in activating the plasma contact system and found that amyloid-beta protofibrils, known to be the most toxic form of amyloid-beta, promoted the activation of this molecular cascade and that lecanemab inhibited pathway activation.

“In our study, we looked at lecanemab and found it can block the activation of the contact system, which could be one of the reasons that it works so well for AD,” study coinvestigator Erin Norris, PhD, research associate professor, Rockefeller University, New York, said in an interview.

The study was published online in the Proceedings of the National Academy of Science.
 

Unknown mechanism

“Many years ago, we started looking at the involvement of vascular dysfunction in AD,” Dr. Norris said. “We wanted to see whether or not irregular blood clotting or problems with blood flow was problematic in Alzheimer’s patients.”

The researchers found that fibrin, a major component involved in blood clotting, can extravasate into the brain.

“The blood-brain barrier can break down in Alzheimer’s, so things from the blood can move into the brain and deposit there,” she added. Fibrin then interacts with amyloid-beta, the major pathogenic protein in AD.

Dr. Norris explained that fibrin clots can form in two different ways. One is through the normal process that occurs when there’s an injury and bleeding. The second is through intrinsic clotting, which takes place through the contact system.

“We started looking into this system and found that the plasma of Alzheimer’s patients showed irregular levels of these enzymes and proteins that are part of the intrinsic clotting system compared to those of normal controls,” said Dr. Norris.

“This paper was an extension of years studying this pathway and these mechanisms. It was also inspired by the approval of lecanemab and its release for use in Alzheimer’s patients,” she added.

In previous research, the same researchers found that amyloid-beta has different forms. “It’s normally soluble, and it’s a very tiny molecule,” Dr. Norris said. “But over time, and in different situations, it can start to aggregate, becoming bigger and bigger.”
 

Implications beyond Alzheimer’s

Postmortem tissue analysis has found fibrillar plaques that are “clumped together.” These are insoluble and hard to get rid of, she said. “Protofibrils are the step before amyloid-beta forms fibrils and are considered to be the most toxic form, although the mechanism behind why it’s so toxic is not understood.”

Previous research has already shown that amyloid-beta can activate the contact system. The contact system has two “arms,” the first of which is involved with clotting, and the second with inflammation, Dr. Norris said. In fact, it’s the plasma contact system that links vascular and inflammatory pathways.

The plasma contact system leads to the clotting of fibrin, Dr. Norris continued. It activates factor XII, which leads to blood clotting by binding to coagulation factor XI.

The contact system also causes inflammation – the second “arm.” Bradykinin, a potent inflammatory molecule, is released by binding to high-molecular-weight kininogen (HK). In addition to inflammation, bradykinin can cause edema and blood-brain barrier permeability.

Although it’s been known that amyloid-beta can activate the contact system, the particular form of amyloid-beta implicated in this cascade has not been identified. And so, the researchers incubated amyloid-beta42 with human plasma, testing various types of amyloid-beta – monomers, oligomers, protofibrils, and fibrils – to see which would activate the contact system.

Amyloid-beta protofibrils promoted the activation of the contact system, as evidenced by several reactions, including activation of factor XII, while other forms of amyloid-beta did not. HK also “bound tightly” to amyloid-beta protofibrils, with “weaker” binding to other amyloid-beta species, the authors reported, confirming that amyloid-beta protofibrils bind to HK and factor XII.

Bradykinin levels were increased by amyloid-beta protofibrils, which also induced faster clotting, compared with other forms of amyloid-beta.

The researchers introduced lecanemab into the picture and found it “dramatically inhibited” contact system activation induced by amyloid-beta protofibrils. For example, it blocked the binding of factor XII to amyloid-beta. By contrast, human IgG (which the researchers used as a control) had no effect.

Additionally, lecanemab also prevented accelerated intrinsic coagulation in normal human plasma mediated by amyloid-beta protofibril.

Senior author Sidney Strickland, PhD, the Zachary and Elizabeth M. Fisher professor in Alzheimer’s and neurodegenerative disease, Rockefeller University, said in an interview: “One of the strong motivators for conducting this study was the fact that this drug, which is effective in AD, targets this specific form of amyloid-beta; but no one knows why it›s more toxic. We thought we could see if we could tie it to what we›re working on, and we found it ties in beautifully.”

The findings have implications that go beyond AD, Dr. Strickland said. “The contact system is implicated in lots of different pathologies, including sickle cell anemia, sepsis, inflammatory bowel disease, and so on.” Blocking the contact system might be a helpful approach in these conditions too.
 

Innovative, plausible, but still preliminary

In a comment, Heather M. Snyder, PhD, vice president of medical and scientific relations at the Alzheimer’s Association, called the investigation “innovative,” with ideas that are “certainly plausible.” However, “at this time, the work is preliminary and not conclusive.”

The hypothesized mechanisms for why amyloid (lecanemab’s target) is toxic to the brain “does incorporate important AD-related brain changes that have been observed in other studies, including inflammatory/immune changes and vascular-related changes,” said Dr. Snyder, who was not involved with the current study.

However, “additional studies that look both in model systems and in humans are needed to further illuminate these relationships,” Dr. Snyder said.

The study was supported by grants from the National Institutes of Health as well as the Robertson Therapeutic Development Fund, Samuel Newhouse Foundation, John A. Herrmann, and the May and Samuel Rudin Family Foundation. Dr. Norris, Dr. Strickland, and Dr. Snyder declared no relevant financial relationships.

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

Lecanemab (Lequembi, Esai), an amyloid-beta–directed antibody therapy, is approved by the Food and Drug Administration for the treatment of Alzheimer’s disease (AD). But exactly how the drug clears amyloid-beta wasn’t clear.

Now new research suggests the drug, which was approved by the FDA in January, targets a particular molecular cascade, the plasma contact system, which drives amyloid-beta toxicity.

The investigators tested the effectiveness of various forms of amyloid-beta in activating the plasma contact system and found that amyloid-beta protofibrils, known to be the most toxic form of amyloid-beta, promoted the activation of this molecular cascade and that lecanemab inhibited pathway activation.

“In our study, we looked at lecanemab and found it can block the activation of the contact system, which could be one of the reasons that it works so well for AD,” study coinvestigator Erin Norris, PhD, research associate professor, Rockefeller University, New York, said in an interview.

The study was published online in the Proceedings of the National Academy of Science.
 

Unknown mechanism

“Many years ago, we started looking at the involvement of vascular dysfunction in AD,” Dr. Norris said. “We wanted to see whether or not irregular blood clotting or problems with blood flow was problematic in Alzheimer’s patients.”

The researchers found that fibrin, a major component involved in blood clotting, can extravasate into the brain.

“The blood-brain barrier can break down in Alzheimer’s, so things from the blood can move into the brain and deposit there,” she added. Fibrin then interacts with amyloid-beta, the major pathogenic protein in AD.

Dr. Norris explained that fibrin clots can form in two different ways. One is through the normal process that occurs when there’s an injury and bleeding. The second is through intrinsic clotting, which takes place through the contact system.

“We started looking into this system and found that the plasma of Alzheimer’s patients showed irregular levels of these enzymes and proteins that are part of the intrinsic clotting system compared to those of normal controls,” said Dr. Norris.

“This paper was an extension of years studying this pathway and these mechanisms. It was also inspired by the approval of lecanemab and its release for use in Alzheimer’s patients,” she added.

In previous research, the same researchers found that amyloid-beta has different forms. “It’s normally soluble, and it’s a very tiny molecule,” Dr. Norris said. “But over time, and in different situations, it can start to aggregate, becoming bigger and bigger.”
 

Implications beyond Alzheimer’s

Postmortem tissue analysis has found fibrillar plaques that are “clumped together.” These are insoluble and hard to get rid of, she said. “Protofibrils are the step before amyloid-beta forms fibrils and are considered to be the most toxic form, although the mechanism behind why it’s so toxic is not understood.”

Previous research has already shown that amyloid-beta can activate the contact system. The contact system has two “arms,” the first of which is involved with clotting, and the second with inflammation, Dr. Norris said. In fact, it’s the plasma contact system that links vascular and inflammatory pathways.

The plasma contact system leads to the clotting of fibrin, Dr. Norris continued. It activates factor XII, which leads to blood clotting by binding to coagulation factor XI.

The contact system also causes inflammation – the second “arm.” Bradykinin, a potent inflammatory molecule, is released by binding to high-molecular-weight kininogen (HK). In addition to inflammation, bradykinin can cause edema and blood-brain barrier permeability.

Although it’s been known that amyloid-beta can activate the contact system, the particular form of amyloid-beta implicated in this cascade has not been identified. And so, the researchers incubated amyloid-beta42 with human plasma, testing various types of amyloid-beta – monomers, oligomers, protofibrils, and fibrils – to see which would activate the contact system.

Amyloid-beta protofibrils promoted the activation of the contact system, as evidenced by several reactions, including activation of factor XII, while other forms of amyloid-beta did not. HK also “bound tightly” to amyloid-beta protofibrils, with “weaker” binding to other amyloid-beta species, the authors reported, confirming that amyloid-beta protofibrils bind to HK and factor XII.

Bradykinin levels were increased by amyloid-beta protofibrils, which also induced faster clotting, compared with other forms of amyloid-beta.

The researchers introduced lecanemab into the picture and found it “dramatically inhibited” contact system activation induced by amyloid-beta protofibrils. For example, it blocked the binding of factor XII to amyloid-beta. By contrast, human IgG (which the researchers used as a control) had no effect.

Additionally, lecanemab also prevented accelerated intrinsic coagulation in normal human plasma mediated by amyloid-beta protofibril.

Senior author Sidney Strickland, PhD, the Zachary and Elizabeth M. Fisher professor in Alzheimer’s and neurodegenerative disease, Rockefeller University, said in an interview: “One of the strong motivators for conducting this study was the fact that this drug, which is effective in AD, targets this specific form of amyloid-beta; but no one knows why it›s more toxic. We thought we could see if we could tie it to what we›re working on, and we found it ties in beautifully.”

The findings have implications that go beyond AD, Dr. Strickland said. “The contact system is implicated in lots of different pathologies, including sickle cell anemia, sepsis, inflammatory bowel disease, and so on.” Blocking the contact system might be a helpful approach in these conditions too.
 

Innovative, plausible, but still preliminary

In a comment, Heather M. Snyder, PhD, vice president of medical and scientific relations at the Alzheimer’s Association, called the investigation “innovative,” with ideas that are “certainly plausible.” However, “at this time, the work is preliminary and not conclusive.”

The hypothesized mechanisms for why amyloid (lecanemab’s target) is toxic to the brain “does incorporate important AD-related brain changes that have been observed in other studies, including inflammatory/immune changes and vascular-related changes,” said Dr. Snyder, who was not involved with the current study.

However, “additional studies that look both in model systems and in humans are needed to further illuminate these relationships,” Dr. Snyder said.

The study was supported by grants from the National Institutes of Health as well as the Robertson Therapeutic Development Fund, Samuel Newhouse Foundation, John A. Herrmann, and the May and Samuel Rudin Family Foundation. Dr. Norris, Dr. Strickland, and Dr. Snyder declared no relevant financial relationships.

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

More than 10 hours a day of sedentary behavior significantly increases the risk of dementia in older adults, a new study suggests.

The study of nearly 50,000 adults in the UK Biobank shows that dementia risk increased 8% with 10 hours of sedentary time and 63% with 12 hours. That’s particularly concerning because Americans spend an average of 9.5 hours a day sitting.

Sleep wasn’t factored into the sedentary time and how someone accumulated the 10 hours – either in one continuous block or broken up throughout the day – was irrelevant.

“Our analysis cannot determine whether there is a causal link, so prescriptive conclusions are not really possible; however. I think it is very reasonable to conclude that sitting less and moving more may help reduce risk of dementia,” lead investigator David Raichlen, PhD, professor of biological sciences and anthropology, University of Southern California, Los Angeles, said in an interview.

The findings were published online in JAMA.
 

A surprising find?

The study is a retrospective analysis of prospectively collected data from the UK Biobank of 49,841 adults aged 60 years or older who wore an accelerometer on their wrists 24 hours a day for a week. Participants had no history of dementia when they wore the movement monitoring device.

Investigators used machine-based learning to determine sedentary time based on readings from the accelerometers. Sleep was not included as sedentary behavior.

Over a mean follow-up of 6.72 years, 414 participants were diagnosed with dementia.

Investigators found that dementia risk rises by 8% at 10 hours a day (adjusted hazard ratio, 1.08; P < .001) and 63% at 12 hours a day (aHR, 1.63; P < .001), compared with 9.27 hours a day. Those who logged 15 hours of sedentary behavior a day had more than triple the dementia risk (aHR, 3.21; P < .001).

Although previous studies had found that breaking up sedentary periods with short bursts of activity help offset some negative health effects of sitting, that wasn’t the case here. Dementia risk was elevated whether participants were sedentary for 10 uninterrupted hours or multiple sedentary periods that totaled 10 hours over the whole day.

“This was surprising,” Dr. Raichlen said. “We expected to find that patterns of sedentary behavior would play a role in risk of dementia, but once you take into account the daily volume of time spent sedentary, how you get there doesn’t seem to matter as much.”

The study did not examine how participants spent sedentary time, but an earlier study by Dr. Raichlen found that watching TV was associated with a greater risk of dementia in older adults, compared with working on a computer.
 

More research welcome

Dr. Raichlen noted that the number of dementia cases in the study is low and that the view of sedentary behavior is based on 1 week of accelerometer readings. A longitudinal study is needed to determine if the findings last over a longer time period.

In a comment, Claire Sexton, DPhil, senior director of scientific programs and outreach for the Alzheimer’s Association, says that earlier studies reported an association between sedentary time and dementia, so these results aren’t “particularly surprising.”

“However, reports that did not find an association have also been published, so additional research on possible associations is welcome,” she said.

It’s also important to note that this observational study doesn’t establish a causal relationship between inactivity and cognitive function, which Dr. Sexton said means the influence of other dementia risk factors that are also exacerbated by sedentary behavior can’t be ruled out.

“Although results remained significant after adjusting for several of these factors, further research is required to better understand the various elements that may influence the observed relationship,” noted Dr. Sexton, who was not part of the study. “Reverse causality – that changes in the brain related to dementia are causing the sedentary behavior – cannot be ruled out.”

The study was funded by the National Institutes of Health, the state of Arizona, the Arizona Department of Health Services, and the McKnight Brain Research Foundation. Dr. Raichlen and Dr. Sexton report no relevant financial relationships.

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

More than 10 hours a day of sedentary behavior significantly increases the risk of dementia in older adults, a new study suggests.

The study of nearly 50,000 adults in the UK Biobank shows that dementia risk increased 8% with 10 hours of sedentary time and 63% with 12 hours. That’s particularly concerning because Americans spend an average of 9.5 hours a day sitting.

Sleep wasn’t factored into the sedentary time and how someone accumulated the 10 hours – either in one continuous block or broken up throughout the day – was irrelevant.

“Our analysis cannot determine whether there is a causal link, so prescriptive conclusions are not really possible; however. I think it is very reasonable to conclude that sitting less and moving more may help reduce risk of dementia,” lead investigator David Raichlen, PhD, professor of biological sciences and anthropology, University of Southern California, Los Angeles, said in an interview.

The findings were published online in JAMA.
 

A surprising find?

The study is a retrospective analysis of prospectively collected data from the UK Biobank of 49,841 adults aged 60 years or older who wore an accelerometer on their wrists 24 hours a day for a week. Participants had no history of dementia when they wore the movement monitoring device.

Investigators used machine-based learning to determine sedentary time based on readings from the accelerometers. Sleep was not included as sedentary behavior.

Over a mean follow-up of 6.72 years, 414 participants were diagnosed with dementia.

Investigators found that dementia risk rises by 8% at 10 hours a day (adjusted hazard ratio, 1.08; P < .001) and 63% at 12 hours a day (aHR, 1.63; P < .001), compared with 9.27 hours a day. Those who logged 15 hours of sedentary behavior a day had more than triple the dementia risk (aHR, 3.21; P < .001).

Although previous studies had found that breaking up sedentary periods with short bursts of activity help offset some negative health effects of sitting, that wasn’t the case here. Dementia risk was elevated whether participants were sedentary for 10 uninterrupted hours or multiple sedentary periods that totaled 10 hours over the whole day.

“This was surprising,” Dr. Raichlen said. “We expected to find that patterns of sedentary behavior would play a role in risk of dementia, but once you take into account the daily volume of time spent sedentary, how you get there doesn’t seem to matter as much.”

The study did not examine how participants spent sedentary time, but an earlier study by Dr. Raichlen found that watching TV was associated with a greater risk of dementia in older adults, compared with working on a computer.
 

More research welcome

Dr. Raichlen noted that the number of dementia cases in the study is low and that the view of sedentary behavior is based on 1 week of accelerometer readings. A longitudinal study is needed to determine if the findings last over a longer time period.

In a comment, Claire Sexton, DPhil, senior director of scientific programs and outreach for the Alzheimer’s Association, says that earlier studies reported an association between sedentary time and dementia, so these results aren’t “particularly surprising.”

“However, reports that did not find an association have also been published, so additional research on possible associations is welcome,” she said.

It’s also important to note that this observational study doesn’t establish a causal relationship between inactivity and cognitive function, which Dr. Sexton said means the influence of other dementia risk factors that are also exacerbated by sedentary behavior can’t be ruled out.

“Although results remained significant after adjusting for several of these factors, further research is required to better understand the various elements that may influence the observed relationship,” noted Dr. Sexton, who was not part of the study. “Reverse causality – that changes in the brain related to dementia are causing the sedentary behavior – cannot be ruled out.”

The study was funded by the National Institutes of Health, the state of Arizona, the Arizona Department of Health Services, and the McKnight Brain Research Foundation. Dr. Raichlen and Dr. Sexton report no relevant financial relationships.

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

More than 10 hours a day of sedentary behavior significantly increases the risk of dementia in older adults, a new study suggests.

The study of nearly 50,000 adults in the UK Biobank shows that dementia risk increased 8% with 10 hours of sedentary time and 63% with 12 hours. That’s particularly concerning because Americans spend an average of 9.5 hours a day sitting.

Sleep wasn’t factored into the sedentary time and how someone accumulated the 10 hours – either in one continuous block or broken up throughout the day – was irrelevant.

“Our analysis cannot determine whether there is a causal link, so prescriptive conclusions are not really possible; however. I think it is very reasonable to conclude that sitting less and moving more may help reduce risk of dementia,” lead investigator David Raichlen, PhD, professor of biological sciences and anthropology, University of Southern California, Los Angeles, said in an interview.

The findings were published online in JAMA.
 

A surprising find?

The study is a retrospective analysis of prospectively collected data from the UK Biobank of 49,841 adults aged 60 years or older who wore an accelerometer on their wrists 24 hours a day for a week. Participants had no history of dementia when they wore the movement monitoring device.

Investigators used machine-based learning to determine sedentary time based on readings from the accelerometers. Sleep was not included as sedentary behavior.

Over a mean follow-up of 6.72 years, 414 participants were diagnosed with dementia.

Investigators found that dementia risk rises by 8% at 10 hours a day (adjusted hazard ratio, 1.08; P < .001) and 63% at 12 hours a day (aHR, 1.63; P < .001), compared with 9.27 hours a day. Those who logged 15 hours of sedentary behavior a day had more than triple the dementia risk (aHR, 3.21; P < .001).

Although previous studies had found that breaking up sedentary periods with short bursts of activity help offset some negative health effects of sitting, that wasn’t the case here. Dementia risk was elevated whether participants were sedentary for 10 uninterrupted hours or multiple sedentary periods that totaled 10 hours over the whole day.

“This was surprising,” Dr. Raichlen said. “We expected to find that patterns of sedentary behavior would play a role in risk of dementia, but once you take into account the daily volume of time spent sedentary, how you get there doesn’t seem to matter as much.”

The study did not examine how participants spent sedentary time, but an earlier study by Dr. Raichlen found that watching TV was associated with a greater risk of dementia in older adults, compared with working on a computer.
 

More research welcome

Dr. Raichlen noted that the number of dementia cases in the study is low and that the view of sedentary behavior is based on 1 week of accelerometer readings. A longitudinal study is needed to determine if the findings last over a longer time period.

In a comment, Claire Sexton, DPhil, senior director of scientific programs and outreach for the Alzheimer’s Association, says that earlier studies reported an association between sedentary time and dementia, so these results aren’t “particularly surprising.”

“However, reports that did not find an association have also been published, so additional research on possible associations is welcome,” she said.

It’s also important to note that this observational study doesn’t establish a causal relationship between inactivity and cognitive function, which Dr. Sexton said means the influence of other dementia risk factors that are also exacerbated by sedentary behavior can’t be ruled out.

“Although results remained significant after adjusting for several of these factors, further research is required to better understand the various elements that may influence the observed relationship,” noted Dr. Sexton, who was not part of the study. “Reverse causality – that changes in the brain related to dementia are causing the sedentary behavior – cannot be ruled out.”

The study was funded by the National Institutes of Health, the state of Arizona, the Arizona Department of Health Services, and the McKnight Brain Research Foundation. Dr. Raichlen and Dr. Sexton report no relevant financial relationships.

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

New research provides strong evidence of an association between abdominal fat and reduced brain volumes, particularly those involved with cognitive function.

In a large study of healthy middle-aged adults, greater visceral and subcutaneous abdominal fat on abdominal MRI predicted brain atrophy on imaging, especially in women.

“The study shows that excess fat is bad for the brain and worse in women, including in Alzheimer’s disease risk regions,” lead author Cyrus Raji, MD, PhD, with the Mallinckrodt Institute of Radiology, Washington University, St. Louis, Mo., said in an interview.

The study was published online in the journal Aging and Disease
 

Modifiable risk factor

Multiple studies have suggested a connection between body fat accumulation and increased dementia risk. But few have examined the relationship between types of fat (visceral and subcutaneous) and brain volume.

For the new study, 10,000 healthy adults aged 20-80 years (mean age, 52.9 years; 53% men) underwent a short whole-body MRI protocol. Regression analyses of abdominal fat types and normalized brain volumes were evaluated, controlling for age and sex.

The research team found that higher amounts of both visceral and subcutaneous abdominal fat predicted lower total gray and white matter volume, as well as lower volume in the hippocampus, frontal cortex, and temporal, parietal, and occipital lobes.

“The findings are quite dramatic,” Dr. Raji told this news organization. “Overall, we found that both subcutaneous and visceral fat has similar levels of negative relationships with brain volumes.”

Women had a higher burden of brain atrophy with increased visceral fat than men. However, it’s difficult to place the sex differences in context because of the lack of prior work specifically investigating visceral fat, brain volume loss, and sex differences, the researchers caution.

They also note that while statistically significant relationships were observed between visceral fat levels and gray matter volume changes, their effect sizes were generally small. 

“Thus, the statistical significance of this work is influenced by the large sample size and less so by large effect size in any given set of regions,” the investigators write.

Other limitations include the cross-sectional nature of the study, which precludes conclusions about causality. The analysis also did not account for other lifestyle factors such as physical activity, diet, and genetic variables.

The researchers call for further investigation “to better elucidate underlying mechanisms and discover possible interventions targeting abdominal fat reduction as a strategy to maintain brain health.”
 

‘Helpful addition to the literature’

In a comment, Claire Sexton, DPhil, Alzheimer’s Association senior director of scientific programs and outreach, noted that “previous studies have linked obesity with cognitive decline and increased risk of dementia. Rather than using BMI as a proxy for body fat, the current study examined visceral and subcutaneous fat directly using imaging techniques.”

Dr. Sexton, who was not associated with this study, said the finding that increased body fat was associated with reduced brain volumes suggests “a possible mechanism to explain the previously reported associations between obesity and cognition.”

“Though some degree of atrophy and brain shrinkage is common with old age, awareness of this association is important because reduced brain volume may be associated with problems with thinking, memory, and performing everyday tasks, and because rates of obesity continue to rise in the United States, along with obesity-related conditions including heart disease, stroke, type 2 diabetes and certain types of cancer,” she added.

“While a helpful addition to the literature, the study does have important limitations. As an observational study, it cannot establish whether higher levels of body fat directly causes reduced brain volumes,” Dr. Sexton cautioned.

In addition, the study did not take into account important related factors like physical activity and diet, which may influence any relationship between body fat and brain volumes, she noted. “Overall, it is not just one factor that is important to consider when considering risk for cognitive decline and dementia, but multiple factors.

“Obesity and the location of body fat must be considered in combination with one’s total lived experience and habits, including physical activity, education, head injury, sleep, mental health, and the health of your heart/cardiovascular system and other key bodily systems,” Dr. Sexton said.

The Alzheimer’s Association is leading a 2-year clinical trial known as U.S. POINTER to see whether combining physical activity, healthy nutrition, social and intellectual challenges, and improved self-management of medical conditions can protect cognitive function in older adults who are at increased risk for cognitive decline.

This work was supported in part by Providence St. Joseph Health in Seattle; Saint John’s Health Center Foundation; Pacific Neuroscience Institute and Foundation; Will and Cary Singleton; and the McLoughlin family. Dr. Raji is a consultant for Brainreader, Apollo Health, Voxelwise, Neurevolution, Pacific Neuroscience Institute Foundation, and Icometrix. Dr. Sexton reports no relevant financial relationships.

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

New research provides strong evidence of an association between abdominal fat and reduced brain volumes, particularly those involved with cognitive function.

In a large study of healthy middle-aged adults, greater visceral and subcutaneous abdominal fat on abdominal MRI predicted brain atrophy on imaging, especially in women.

“The study shows that excess fat is bad for the brain and worse in women, including in Alzheimer’s disease risk regions,” lead author Cyrus Raji, MD, PhD, with the Mallinckrodt Institute of Radiology, Washington University, St. Louis, Mo., said in an interview.

The study was published online in the journal Aging and Disease
 

Modifiable risk factor

Multiple studies have suggested a connection between body fat accumulation and increased dementia risk. But few have examined the relationship between types of fat (visceral and subcutaneous) and brain volume.

For the new study, 10,000 healthy adults aged 20-80 years (mean age, 52.9 years; 53% men) underwent a short whole-body MRI protocol. Regression analyses of abdominal fat types and normalized brain volumes were evaluated, controlling for age and sex.

The research team found that higher amounts of both visceral and subcutaneous abdominal fat predicted lower total gray and white matter volume, as well as lower volume in the hippocampus, frontal cortex, and temporal, parietal, and occipital lobes.

“The findings are quite dramatic,” Dr. Raji told this news organization. “Overall, we found that both subcutaneous and visceral fat has similar levels of negative relationships with brain volumes.”

Women had a higher burden of brain atrophy with increased visceral fat than men. However, it’s difficult to place the sex differences in context because of the lack of prior work specifically investigating visceral fat, brain volume loss, and sex differences, the researchers caution.

They also note that while statistically significant relationships were observed between visceral fat levels and gray matter volume changes, their effect sizes were generally small. 

“Thus, the statistical significance of this work is influenced by the large sample size and less so by large effect size in any given set of regions,” the investigators write.

Other limitations include the cross-sectional nature of the study, which precludes conclusions about causality. The analysis also did not account for other lifestyle factors such as physical activity, diet, and genetic variables.

The researchers call for further investigation “to better elucidate underlying mechanisms and discover possible interventions targeting abdominal fat reduction as a strategy to maintain brain health.”
 

‘Helpful addition to the literature’

In a comment, Claire Sexton, DPhil, Alzheimer’s Association senior director of scientific programs and outreach, noted that “previous studies have linked obesity with cognitive decline and increased risk of dementia. Rather than using BMI as a proxy for body fat, the current study examined visceral and subcutaneous fat directly using imaging techniques.”

Dr. Sexton, who was not associated with this study, said the finding that increased body fat was associated with reduced brain volumes suggests “a possible mechanism to explain the previously reported associations between obesity and cognition.”

“Though some degree of atrophy and brain shrinkage is common with old age, awareness of this association is important because reduced brain volume may be associated with problems with thinking, memory, and performing everyday tasks, and because rates of obesity continue to rise in the United States, along with obesity-related conditions including heart disease, stroke, type 2 diabetes and certain types of cancer,” she added.

“While a helpful addition to the literature, the study does have important limitations. As an observational study, it cannot establish whether higher levels of body fat directly causes reduced brain volumes,” Dr. Sexton cautioned.

In addition, the study did not take into account important related factors like physical activity and diet, which may influence any relationship between body fat and brain volumes, she noted. “Overall, it is not just one factor that is important to consider when considering risk for cognitive decline and dementia, but multiple factors.

“Obesity and the location of body fat must be considered in combination with one’s total lived experience and habits, including physical activity, education, head injury, sleep, mental health, and the health of your heart/cardiovascular system and other key bodily systems,” Dr. Sexton said.

The Alzheimer’s Association is leading a 2-year clinical trial known as U.S. POINTER to see whether combining physical activity, healthy nutrition, social and intellectual challenges, and improved self-management of medical conditions can protect cognitive function in older adults who are at increased risk for cognitive decline.

This work was supported in part by Providence St. Joseph Health in Seattle; Saint John’s Health Center Foundation; Pacific Neuroscience Institute and Foundation; Will and Cary Singleton; and the McLoughlin family. Dr. Raji is a consultant for Brainreader, Apollo Health, Voxelwise, Neurevolution, Pacific Neuroscience Institute Foundation, and Icometrix. Dr. Sexton reports no relevant financial relationships.

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

New research provides strong evidence of an association between abdominal fat and reduced brain volumes, particularly those involved with cognitive function.

In a large study of healthy middle-aged adults, greater visceral and subcutaneous abdominal fat on abdominal MRI predicted brain atrophy on imaging, especially in women.

“The study shows that excess fat is bad for the brain and worse in women, including in Alzheimer’s disease risk regions,” lead author Cyrus Raji, MD, PhD, with the Mallinckrodt Institute of Radiology, Washington University, St. Louis, Mo., said in an interview.

The study was published online in the journal Aging and Disease
 

Modifiable risk factor

Multiple studies have suggested a connection between body fat accumulation and increased dementia risk. But few have examined the relationship between types of fat (visceral and subcutaneous) and brain volume.

For the new study, 10,000 healthy adults aged 20-80 years (mean age, 52.9 years; 53% men) underwent a short whole-body MRI protocol. Regression analyses of abdominal fat types and normalized brain volumes were evaluated, controlling for age and sex.

The research team found that higher amounts of both visceral and subcutaneous abdominal fat predicted lower total gray and white matter volume, as well as lower volume in the hippocampus, frontal cortex, and temporal, parietal, and occipital lobes.

“The findings are quite dramatic,” Dr. Raji told this news organization. “Overall, we found that both subcutaneous and visceral fat has similar levels of negative relationships with brain volumes.”

Women had a higher burden of brain atrophy with increased visceral fat than men. However, it’s difficult to place the sex differences in context because of the lack of prior work specifically investigating visceral fat, brain volume loss, and sex differences, the researchers caution.

They also note that while statistically significant relationships were observed between visceral fat levels and gray matter volume changes, their effect sizes were generally small. 

“Thus, the statistical significance of this work is influenced by the large sample size and less so by large effect size in any given set of regions,” the investigators write.

Other limitations include the cross-sectional nature of the study, which precludes conclusions about causality. The analysis also did not account for other lifestyle factors such as physical activity, diet, and genetic variables.

The researchers call for further investigation “to better elucidate underlying mechanisms and discover possible interventions targeting abdominal fat reduction as a strategy to maintain brain health.”
 

‘Helpful addition to the literature’

In a comment, Claire Sexton, DPhil, Alzheimer’s Association senior director of scientific programs and outreach, noted that “previous studies have linked obesity with cognitive decline and increased risk of dementia. Rather than using BMI as a proxy for body fat, the current study examined visceral and subcutaneous fat directly using imaging techniques.”

Dr. Sexton, who was not associated with this study, said the finding that increased body fat was associated with reduced brain volumes suggests “a possible mechanism to explain the previously reported associations between obesity and cognition.”

“Though some degree of atrophy and brain shrinkage is common with old age, awareness of this association is important because reduced brain volume may be associated with problems with thinking, memory, and performing everyday tasks, and because rates of obesity continue to rise in the United States, along with obesity-related conditions including heart disease, stroke, type 2 diabetes and certain types of cancer,” she added.

“While a helpful addition to the literature, the study does have important limitations. As an observational study, it cannot establish whether higher levels of body fat directly causes reduced brain volumes,” Dr. Sexton cautioned.

In addition, the study did not take into account important related factors like physical activity and diet, which may influence any relationship between body fat and brain volumes, she noted. “Overall, it is not just one factor that is important to consider when considering risk for cognitive decline and dementia, but multiple factors.

“Obesity and the location of body fat must be considered in combination with one’s total lived experience and habits, including physical activity, education, head injury, sleep, mental health, and the health of your heart/cardiovascular system and other key bodily systems,” Dr. Sexton said.

The Alzheimer’s Association is leading a 2-year clinical trial known as U.S. POINTER to see whether combining physical activity, healthy nutrition, social and intellectual challenges, and improved self-management of medical conditions can protect cognitive function in older adults who are at increased risk for cognitive decline.

This work was supported in part by Providence St. Joseph Health in Seattle; Saint John’s Health Center Foundation; Pacific Neuroscience Institute and Foundation; Will and Cary Singleton; and the McLoughlin family. Dr. Raji is a consultant for Brainreader, Apollo Health, Voxelwise, Neurevolution, Pacific Neuroscience Institute Foundation, and Icometrix. Dr. Sexton reports no relevant financial relationships.

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

I’m really going to miss Jimmy Buffett.

I’ve liked his music as far back as I can remember, and was lucky enough to see him in person in the mid-90s.

I’ve written about music before, but its affect on us never fails to amaze me. Songs can be background noise conducive to getting things done. They can also be in the foreground, serving as a mental vacation (or accompanying a real one). They can transport you to another place, briefly clearing your head from the daily goings-on around you. Even if it’s just during the drive home, it’s a welcome escape to a virtual beach and tropical drink.

Songs can bring back memories of certain events or people that we link them to. My dad loved anything by Neil Diamond, and nothing brings back thoughts of Dad more than when my iTunes randomly picks “I Am ... I Said.” Or John Williams’ Star Wars theme, taking me back to the summer of 1977 when I sat, spellbound, by this incredible movie whose magic is still going strong two generations later.

It’s amazing how our brain tries to make music out of nothing. Even in silence we have ear worms, the songs stuck in our head for hours to days (recently I’ve had “I Sing the Body Electric” from the 1980 movie Fame playing in there).

My office is over an MRI scanner, so I can always hear the chiller pumps softly running in the background. Sometimes my brain will turn their rhythmic chirping into a song, altering the pace of the song to fit them. The soft clicking of the ceiling fan, in my home office, does the same thing (for some reason my brain usually tries to fit “Yellow Submarine” to that one, no idea why).

Music is a part of that mysterious essence that makes us human. It touches all of us in some way, which varies between people, songs, and artists.

Jimmy Buffet’s music has a vacation vibe. Songs of the Caribbean & Keys, beaches, bars, boats, and tropical drinks. The 4:12 running time of his most well-known song, “Margaritaville,” gives a brief respite from my day when it comes on.

He passes into the beyond, to the sadness of his family, friends, and fans. But, unlike people, music can be immortal, and so he lives on through his creations. Like, Bach, Lennon, Bowie, Joplin, Sousa, and too many others to count, his work – and the enjoyment we get from it – are a gift left behind for the future.

Tight lines, Jimmy.

Dr. Block has a solo neurology practice in Scottsdale, Ariz.

I’m really going to miss Jimmy Buffett.

I’ve liked his music as far back as I can remember, and was lucky enough to see him in person in the mid-90s.

I’ve written about music before, but its affect on us never fails to amaze me. Songs can be background noise conducive to getting things done. They can also be in the foreground, serving as a mental vacation (or accompanying a real one). They can transport you to another place, briefly clearing your head from the daily goings-on around you. Even if it’s just during the drive home, it’s a welcome escape to a virtual beach and tropical drink.

Songs can bring back memories of certain events or people that we link them to. My dad loved anything by Neil Diamond, and nothing brings back thoughts of Dad more than when my iTunes randomly picks “I Am ... I Said.” Or John Williams’ Star Wars theme, taking me back to the summer of 1977 when I sat, spellbound, by this incredible movie whose magic is still going strong two generations later.

It’s amazing how our brain tries to make music out of nothing. Even in silence we have ear worms, the songs stuck in our head for hours to days (recently I’ve had “I Sing the Body Electric” from the 1980 movie Fame playing in there).

My office is over an MRI scanner, so I can always hear the chiller pumps softly running in the background. Sometimes my brain will turn their rhythmic chirping into a song, altering the pace of the song to fit them. The soft clicking of the ceiling fan, in my home office, does the same thing (for some reason my brain usually tries to fit “Yellow Submarine” to that one, no idea why).

Music is a part of that mysterious essence that makes us human. It touches all of us in some way, which varies between people, songs, and artists.

Jimmy Buffet’s music has a vacation vibe. Songs of the Caribbean & Keys, beaches, bars, boats, and tropical drinks. The 4:12 running time of his most well-known song, “Margaritaville,” gives a brief respite from my day when it comes on.

He passes into the beyond, to the sadness of his family, friends, and fans. But, unlike people, music can be immortal, and so he lives on through his creations. Like, Bach, Lennon, Bowie, Joplin, Sousa, and too many others to count, his work – and the enjoyment we get from it – are a gift left behind for the future.

Tight lines, Jimmy.

Dr. Block has a solo neurology practice in Scottsdale, Ariz.

I’m really going to miss Jimmy Buffett.

I’ve liked his music as far back as I can remember, and was lucky enough to see him in person in the mid-90s.

I’ve written about music before, but its affect on us never fails to amaze me. Songs can be background noise conducive to getting things done. They can also be in the foreground, serving as a mental vacation (or accompanying a real one). They can transport you to another place, briefly clearing your head from the daily goings-on around you. Even if it’s just during the drive home, it’s a welcome escape to a virtual beach and tropical drink.

Songs can bring back memories of certain events or people that we link them to. My dad loved anything by Neil Diamond, and nothing brings back thoughts of Dad more than when my iTunes randomly picks “I Am ... I Said.” Or John Williams’ Star Wars theme, taking me back to the summer of 1977 when I sat, spellbound, by this incredible movie whose magic is still going strong two generations later.

It’s amazing how our brain tries to make music out of nothing. Even in silence we have ear worms, the songs stuck in our head for hours to days (recently I’ve had “I Sing the Body Electric” from the 1980 movie Fame playing in there).

My office is over an MRI scanner, so I can always hear the chiller pumps softly running in the background. Sometimes my brain will turn their rhythmic chirping into a song, altering the pace of the song to fit them. The soft clicking of the ceiling fan, in my home office, does the same thing (for some reason my brain usually tries to fit “Yellow Submarine” to that one, no idea why).

Music is a part of that mysterious essence that makes us human. It touches all of us in some way, which varies between people, songs, and artists.

Jimmy Buffet’s music has a vacation vibe. Songs of the Caribbean & Keys, beaches, bars, boats, and tropical drinks. The 4:12 running time of his most well-known song, “Margaritaville,” gives a brief respite from my day when it comes on.

He passes into the beyond, to the sadness of his family, friends, and fans. But, unlike people, music can be immortal, and so he lives on through his creations. Like, Bach, Lennon, Bowie, Joplin, Sousa, and too many others to count, his work – and the enjoyment we get from it – are a gift left behind for the future.

Tight lines, Jimmy.

Dr. Block has a solo neurology practice in Scottsdale, Ariz.