Diabetes mellitus and risk of Alzheimer's disease and dementia with strokein a multiethnic cohort

Research on the relation between diabetes mellitus and dementia has produce d conflicting results, and the relation has not been investigated among Bla cks and Hispanics. In this study, Cox proportional hazards models were used to analyze longitudinal data from 1,262 elderly subjects without dementia at baseline (1991-1996) who were followed for an average of 4.3 years betwe en 1992 and 1997. Outcomes were incident Alzheimer's disease and dementia a ssociated with stroke. The prevalence of diabetes was 20% at baseline. The adjusted relative risk of Alzheimer's disease among persons with diabetes a s compared with those without diabetes was 1.3 (95% confidence interval (CI ): 0.8, 1.9). The adjusted relative risk for the composite outcome of Alzhe imer's disease and cognitive impairment without dementia (without stroke) i n subjects with diabetes was 1.6 (95% CI: 1.2, 2.1). The adjusted relative risk of stroke-associated dementia in persons with diabetes was 3.4 (95% CI : 1.7, 6.9). Among Blacks and Hispanics, approximately one third of the ris k of stroke-associated dementia was attributable to diabetes (33% (95% CI: 31, 36) and 36% (95% CI: 33, 37), respectively), as compared with 17% (95% CI: 13, 22) among Whites. The finding of an association between diabetes an d the composite outcome of Alzheimer's disease and cognitive impairment wit hout dementia (without stroke) is consistent with prior reports of a modest relation between diabetes and Alzheimer's disease.