RISK OF DEMENTIA AMONG PERSONS WITH DIABETES-MELLITUS - A POPULATION-BASED COHORT STUDY

It is unclear whether persons with diabetes are at increased risk for dementia, including Alzheimer's disease. Existing studies are limited by small sample size, selection bias, and case-control designs. This p opulation-based historical cohort study provides estimates of the risk of dementia and Alzheimer's disease associated with adult onset diabe tes mellitus (AODM). The sample included all persons with AODM residin g in Rochester, Minnesota, on January 1, 1970, plus all persons diagno sed in Rochester or who moved to Rochester with the diagnosis between January 1, 1970, and December 31, 1984. Individuals were followed thro ugh review of their complete medical records from AODM diagnosis until dementia onset, emigration, death, or January 1, 1985. Standardized m orbidity ratios for dementia and Alzheimer's disease were calculated, using an expected incidence based on age- and sex-specific rates for t he Rochester population. Poisson regression was used to estimate risks for persons with AODM relative to those without. Of the 1,455 cases o f AODM followed for 9,981 person-years, 101 developed dementia, includ ing 77 who met criteria for Alzheimer's disease. Persons with AODM exh ibited significantly increased risk of all dementia (Poisson regressio n relative risk(RR) = 1.66, 95% confidence interval (Cl) 1.34-2.05). R isk of Alzheimer's disease was also elevated (for men, RR = 2.27, 95% CI 1.55-3.31; for women, RR = 1.37, 95% Cl 0.94-2.01). These findings emphasize the importance of AODM prevention and prompt additional inve stigation of the relation between AODM and dementia.