Forty-one percent of women age 85 and older – members of the so-called “oldest old” age cohort – had clinically significant cognitive impairment or dementia, in a study led by Kristine Yaffe, MD, chief of geriatric psychiatry at the San Francisco VA Medical Center.
“The oldest old are the fastest-growing segment of the U.S. population, with a known high risk for developing serious cognitive problems,” said Yaffe. “However, the nature and extent of those problems have not been well-characterized by researchers until now. This is one of the first studies to analyze the types of cognitive deficits experienced by the oldest old, whose population is expected to increase 40 percent in the next decade.”
Since the treatment and expected course of dementia depend on the specific type of impairment, screening of the oldest old is absolutely vital from a public health perspective, said Yaffe, who is also associate chair for clinical and translational research in psychiatry and professor of psychiatry, neurology, and epidemiology and biostatistics at the University of California, San Francisco.
The results of the national multi-center prospective study of 1,299 women, called the Women Cognitive Impairment Study of Exceptional Aging (WISE), appear in the May 2011 issue of Archives of Neurology.
In total, 231 women (17.8 percent) were diagnosed with dementia and 301 (23.2 percent) were diagnosed with mild cognitive impairment (MCI), which is known to be a risk factor for more serious cognitive problems. Women 90 years and older had a dementia rate more than double that of women 85 to 89 years – 28.2 percent versus 13.9 percent.
Of the women with dementia, 80 percent were diagnosed with Alzheimer’s disease or mixed dementia, and 12.1 percent were diagnosed with vascular dementia, which is caused by reduced blood flow to the brain.
Women with dementia were more likely to be older, live in a nursing home, have reported depression, have a history of stroke, and have the APOE e4 gene known to be associated with a greater risk of dementia; they were less likely to have completed high school.
MCI was also more common in women 90 and older – 24.5 percent compared with 22.7 percent for women 85 to 89. Of the women with MCI, 33.9 percent were diagnosed with amnestic multiple domain MCI, which affects multiple cognitive processes including memory, and 28.9 percent were diagnosed with non-amnestic single domain MCI, which affects one type of cognitive function and does not affect memory.
The women in WISE, who were enrolled between 1986 and 1988 and cognitively assessed between 2006 and 2008, were participants in the larger Study of Osteoporotic Fractures, a multi-center prospective study coordinated by UCSF and funded by the National Institutes of Health.
Co-authors of the study are Laura E. Middleton, PhD, of Sunnybrook Hospital, Toronto, Ontario, Canada; Li-Yung Lui, MA, MS, of California Pacific Medical Center, San Francisco; Adam P. Spyra, PhD, of The Johns Hopkins Bloomberg School of Public Health; Katie Stone, PhD, of CPMC; Caroline Racine, PhD, of UCSF; Kristine E. Ensrud, MD, of VAMC Minneapolis, MN; and Joel H. Kramer, PsyD, of UCSF.
The study was supported by funds from the National Institute of Aging, the Alzheimer’s Association, the Canadian Institute of Health, and multiple other grants from the NIH.
SFVAMC has the largest medical research program in the national VA system, with more than 200 research scientists, all of whom are faculty members at UCSF.