Dementia Continues to Rise Among Even the Oldest Old

VIENNA – Dementia does not appear to spare the oldest old, contrary to findings of prior studies suggesting that the incidence tapers off after age 85.

Studies presented at the International Conference on Alzheimer's Disease suggest that dementia rates continue their linear increase even as people approach 100, with a doubling of incidence every 5 years.

“We believe there is now convincing evidence that, unfortunately, this disorder does not go down with age,” Dr. Claudia H. Kawas said at the meeting, which was sponsored by the Alzheimer's Association. The findings are especially important, given that the population of those 90 years and older will increase 10-fold by the middle of this century, said Dr. Kawas, the Al and Trish Nichols Chair in Clinical Neuroscience at the University of California, Irvine. “As more individuals live to these extreme ages, dementia in the oldest old could become an epidemic with enormous public health impact.”

Dr. Kawas and her colleagues presented data from The 90+ Study, a population-based study established in the early 1980s in a California retirement community. Out of the original 14,000 enrolled, her substudy comprised 330 who were aged 90 years or older at the beginning of 2003, available for in-person interviews, and nondemented.

At baseline, the participants ranged in age from 90–108 years; the mean age was 94 years. Most (54%) were still living alone; 29% were living at home with a relative; and 17% were in a group facility or nursing home. Seventy percent were women.

Assessments occurred every 6 months through Jan. 1, 2008, and included a neurologic exam, neuropsychiatric testing, informative questionnaires, and medical records. The mean follow-up time was a little longer than 2 years; almost 400 person-years of follow-up data were collected overall, with 50 person-years of data on those who were 100 years or older. “As far as I know, this is the largest study of dementia in centenarians ever done,” Dr. Kawas said.

By the end of the study, 140 cases of dementia had developed: 49 in those aged 90–94; 71 in those aged 95–99; and 20 in those aged 100 and older. The rate was 18% for both men and women.

The investigators found that the risk of dementia doubled every 5 years, from 10% for the 90- to 94-year-olds to 20% for the 95- to 99-year-olds, and 41% for those 100 and older.

An Italian study that examined dementia rates in people 80 years and older came to similar conclusions. “Although not increasing exponentially, the overall prevalence and incidence rates of dementia continue to rise in very old age,” Dr. Ugo Lucca of Istituto di Ricerche Farmacologiche “Mario Negri,” Milan, wrote in his poster.

Dr. Lucca and his colleagues examined the rate of new-onset dementia in subjects older than 80 years, who were followed for a mean of 3 years. The Monzino 80-plus Study gathered baseline information on 2,138 residents of eight municipalities in Varese province, Italy. Most of the assessment information was gathered at a first visit that occurred at the subjects' residence.

The assessment included neuropsychiatric testing, functional status, and mood and behavioral assessments. Those who screened positive for dementia received additional testing to make a more specific determination of their cognitive status.

VIENNA – Dementia does not appear to spare the oldest old, contrary to findings of prior studies suggesting that the incidence tapers off after age 85.

Studies presented at the International Conference on Alzheimer's Disease suggest that dementia rates continue their linear increase even as people approach 100, with a doubling of incidence every 5 years.

“We believe there is now convincing evidence that, unfortunately, this disorder does not go down with age,” Dr. Claudia H. Kawas said at the meeting, which was sponsored by the Alzheimer's Association. The findings are especially important, given that the population of those 90 years and older will increase 10-fold by the middle of this century, said Dr. Kawas, the Al and Trish Nichols Chair in Clinical Neuroscience at the University of California, Irvine. “As more individuals live to these extreme ages, dementia in the oldest old could become an epidemic with enormous public health impact.”

Dr. Kawas and her colleagues presented data from The 90+ Study, a population-based study established in the early 1980s in a California retirement community. Out of the original 14,000 enrolled, her substudy comprised 330 who were aged 90 years or older at the beginning of 2003, available for in-person interviews, and nondemented.

At baseline, the participants ranged in age from 90–108 years; the mean age was 94 years. Most (54%) were still living alone; 29% were living at home with a relative; and 17% were in a group facility or nursing home. Seventy percent were women.

Assessments occurred every 6 months through Jan. 1, 2008, and included a neurologic exam, neuropsychiatric testing, informative questionnaires, and medical records. The mean follow-up time was a little longer than 2 years; almost 400 person-years of follow-up data were collected overall, with 50 person-years of data on those who were 100 years or older. “As far as I know, this is the largest study of dementia in centenarians ever done,” Dr. Kawas said.

By the end of the study, 140 cases of dementia had developed: 49 in those aged 90–94; 71 in those aged 95–99; and 20 in those aged 100 and older. The rate was 18% for both men and women.

The investigators found that the risk of dementia doubled every 5 years, from 10% for the 90- to 94-year-olds to 20% for the 95- to 99-year-olds, and 41% for those 100 and older.

An Italian study that examined dementia rates in people 80 years and older came to similar conclusions. “Although not increasing exponentially, the overall prevalence and incidence rates of dementia continue to rise in very old age,” Dr. Ugo Lucca of Istituto di Ricerche Farmacologiche “Mario Negri,” Milan, wrote in his poster.

Dr. Lucca and his colleagues examined the rate of new-onset dementia in subjects older than 80 years, who were followed for a mean of 3 years. The Monzino 80-plus Study gathered baseline information on 2,138 residents of eight municipalities in Varese province, Italy. Most of the assessment information was gathered at a first visit that occurred at the subjects' residence.

The assessment included neuropsychiatric testing, functional status, and mood and behavioral assessments. Those who screened positive for dementia received additional testing to make a more specific determination of their cognitive status.

VIENNA – Dementia does not appear to spare the oldest old, contrary to findings of prior studies suggesting that the incidence tapers off after age 85.

Studies presented at the International Conference on Alzheimer's Disease suggest that dementia rates continue their linear increase even as people approach 100, with a doubling of incidence every 5 years.

“We believe there is now convincing evidence that, unfortunately, this disorder does not go down with age,” Dr. Claudia H. Kawas said at the meeting, which was sponsored by the Alzheimer's Association. The findings are especially important, given that the population of those 90 years and older will increase 10-fold by the middle of this century, said Dr. Kawas, the Al and Trish Nichols Chair in Clinical Neuroscience at the University of California, Irvine. “As more individuals live to these extreme ages, dementia in the oldest old could become an epidemic with enormous public health impact.”

Dr. Kawas and her colleagues presented data from The 90+ Study, a population-based study established in the early 1980s in a California retirement community. Out of the original 14,000 enrolled, her substudy comprised 330 who were aged 90 years or older at the beginning of 2003, available for in-person interviews, and nondemented.

At baseline, the participants ranged in age from 90–108 years; the mean age was 94 years. Most (54%) were still living alone; 29% were living at home with a relative; and 17% were in a group facility or nursing home. Seventy percent were women.

Assessments occurred every 6 months through Jan. 1, 2008, and included a neurologic exam, neuropsychiatric testing, informative questionnaires, and medical records. The mean follow-up time was a little longer than 2 years; almost 400 person-years of follow-up data were collected overall, with 50 person-years of data on those who were 100 years or older. “As far as I know, this is the largest study of dementia in centenarians ever done,” Dr. Kawas said.

By the end of the study, 140 cases of dementia had developed: 49 in those aged 90–94; 71 in those aged 95–99; and 20 in those aged 100 and older. The rate was 18% for both men and women.

The investigators found that the risk of dementia doubled every 5 years, from 10% for the 90- to 94-year-olds to 20% for the 95- to 99-year-olds, and 41% for those 100 and older.

An Italian study that examined dementia rates in people 80 years and older came to similar conclusions. “Although not increasing exponentially, the overall prevalence and incidence rates of dementia continue to rise in very old age,” Dr. Ugo Lucca of Istituto di Ricerche Farmacologiche “Mario Negri,” Milan, wrote in his poster.

Dr. Lucca and his colleagues examined the rate of new-onset dementia in subjects older than 80 years, who were followed for a mean of 3 years. The Monzino 80-plus Study gathered baseline information on 2,138 residents of eight municipalities in Varese province, Italy. Most of the assessment information was gathered at a first visit that occurred at the subjects' residence.

The assessment included neuropsychiatric testing, functional status, and mood and behavioral assessments. Those who screened positive for dementia received additional testing to make a more specific determination of their cognitive status.