To determine the prevalence of mild cognitive impairment (MCI), dementia and subtypes among oldest old women.
Prospective cohort study
Women, Cognitive Impairment Study of Exceptional Aging
1299 oldest old (≥ 85 years) women
Main Outcome Measures
All women completed a neuropsychological test battery. Those who screened positive for possible cognitive impairment (n=634) were further assessed for a diagnosis of dementia, MCI, or normal by an expert panel. Remaining women were considered cognitively normal. Dementia and MCI subtypes were determined using standard criteria.
The women had a mean age of 88.2 years and 27.0% were ≥90 years; 231 women (17.8%) were diagnosed with dementia and 301 (23.2%) with MCI for a combined cognitive impairment prevalence of 41.0%. Clinical features consistent with Alzheimer’s disease and mixed dementia were most common, each accounting for 40% of dementia cases. Amnestic multiple domain and non-amnestic single domain were the most common MCI types, accounting for 33.9% and 28.9% of cases respectively. Cognitive impairment was more frequent among women ≥90 years compared to those 85–89 years (dementia 28.2% vs. 13.9%, p<0.0001, and MCI 24.5% v. 22.7%, p=0.02) and more common among women with less education, history of stroke, and prevalent depression.
In this large sample of oldest old women, approximately 40% had clinically adjudicated cognitive impairment. Subtypes of dementia and MCI were similar to younger populations. Our results suggest that women in the fastest growing demographic, the oldest old, should be carefully screened for cognitive disorders, especially high risk groups.