Question  Has the incidence of all-cause dementia decreased in successive birth cohorts in a representative sample of community-residing adults in Bronx County, New York? Findings  Using a birth cohort analysis to disentangle age from cohort effects, this study found that dementia incidence rates decreased significantly among individuals born after 1929. Adjustment for age, sex, educational level, and prevalence of cardiovascular comorbidities did not explain the observed trend. Please contact the library to request a copy of this article - http://bit.ly/1Xyazai