Gender and incidence of dementia in the Framingham Heart Study from mid-adult life.
Level 3 - non-randomized controlled study
Prospective observational cohort study
PubMed 24418058 · doi:10.1016/j.jalz.2013.10.005
What was done
Data from 7,901 Framingham Heart Study participants (4,333 women) followed over 136,266 person-years were analyzed to calculate 10- to 50-year risk estimates of incident dementia and Alzheimer's disease (AD) starting in midlife. Risk was evaluated using standard Kaplan-Meier cumulative incidence as well as lifetime risk (LTR) models accounting for the competing risk of death, alongside age-stratified cardiovascular mortality.
What was found
A total of 777 incident dementia cases (including 601 AD cases) occurred during follow-up. Standard cumulative incidences were similar between sexes, but lifetime risk accounting for competing mortality was higher in women older than 85 years. At age 45, the estimated lifetime risk of dementia/AD was 1 in 5 for women and 1 in 10 for men. Cardiovascular mortality was markedly higher in men, with male-to-female rate ratios decreasing from approximately 6 at ages 45–54 to less than 2 after age 65.
Why it matters
This study demonstrates that the higher lifetime risk of dementia observed in women is partly an artifact of selective survival, as higher midlife cardiovascular mortality selectively removes men with worse vascular risk profiles prior to the age of dementia onset.
Limits
The Framingham Heart Study cohort consists almost entirely of individuals of European descent, limiting generalizability to other racial and ethnic groups. The abstract does not provide confidence intervals or formal statistical test metrics for the reported risk estimates, nor does it detail specific adjustments for education, lifestyle, or APOE genotype.
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