Declining Incidence of Dementia in the Framingham Heart Study

The prevalence of dementia is expected to increase as average life expectancy increases. However, data from the Framingham Heart Study suggest a different trend. Researchers analyzed the incidence of dementia since 1975 in 5205 dementia-free study participants (age, ≥60 years). A neurologist and neuropsychologist reviewed each case of possible cognitive impairment identified through screening and used published criteria to diagnose dementia.

For each consecutive epoch (1977–1983, 1986–1991, 1992–1998, and 2004–2008), the 5-year age- and sex-adjusted cumulative hazard ratios for dementia were 3.6, 2.8, 2.2, and 2.0 per 100 persons, respectively. The decline in dementia incidence averaged 20% per decade, was limited to those with a high school…