Type 2 diabetes and late-onset Alzheimer's disease.

BACKGROUND/AIMS To confirm in a cohort recruited in 1999-2001 our finding in a cohort recruited in 1992-1994 relating type 2 diabetes (T2D) to late-onset Alzheimer's disease (LOAD). METHODS Participants were 1,488 persons aged 65 years and older without dementia at baseline from New York City. T2D was ascertained by self-report. Dementia and LOAD were ascertained by standard research procedures. Proportional hazard regression was used for analyses relating T2D and LOAD. RESULTS The prevalence of T2D was 17%. There were 161 cases of dementia and 149 cases of LOAD. T2D was related to dementia (hazard ratio = 1.7; 95% confidence interval = 1.4-2.9) and LOAD (1.6; 1.0-2.6) after adjustment for age, sex, education, ethnic group and apolipoprotein E ε4. This association was weaker when only AD - excluding cases of mixed dementia - was considered (hazard ratio = 1.3; 95% confidence interval = 0.8-2.2). CONCLUSION T2D is associated with LOAD. Cerebrovascular disease may be an important mediator.