History of Medically Treated Diabetes and Risk of Alzheimer Disease in a Nationwide Case-Control Study

OBJECTIVEdType 2 diabetes in midlife or late life increases the risk of Alzheimer disease (AD), and type 1 diabetes has been associated with a higher risk of detrimental cognitive out-comes, although studies from older adults are lacking. We investigated whether individuals with AD were more likely to have a history of diabetes than matched controls from the general aged population. RESEARCH DESIGN ANDMETHODSdInformation on reimbursed diabetes medica-tion (including both type 1 and 2 diabetes) of all Finnish individuals with reimbursed AD medication in 2005 (n = 28,093) and their AD-free control subjects during 1972–2005 was obtained from a special reimbursement register maintained by the Social Insurance Institute of Finland. RESULTSdThe prevalence of diabetes was 11.4 % in the whole study population, 10.7 % (n = 3,012) among control subjects, and 12.0 % (n = 3,372) among AD case subjects. People with AD were more likely to have diabetes than matched control subjects (unadjusted OR 1.14 [95 % CI 1.08–1.20]), even after adjusting for cardiovascular diseases (OR 1.31 [1.22–1.41]). The asso-ciations were stronger with diabetes diagnosed at midlife (adjusted OR 1.60 [1.34–1.84] an