Diabetes mellitus in midlife and the risk of dementia three decades later

Objective: To examine the association between diabetes in midlife (1963-1968) and dementia more than three decades later (1999-2001). Methods: The authors characterized dementia using standard methods for 1,892 participants among 2,606 survivors of 10,059 participants in the Israeli Ischemic Heart Disease study, a longitudinal investigation of the incidence of and risk factors for cardiovascular disease among Jewish male civil servants in Israel. Face to face interviews were conducted with the 652 subjects identified as possibly demented by the Modified Telephone Interview for Cognitive Status. Logistic regression analysis was performed to assess the association of diabetes with dementia controlling for sociodemographic and cardiovascular variables compared to those with no cognitive impairment. Results: Of 1,892 assessed subjects (mean age 82 at assessment), 309 (16.3%) had dementia. Diabetic subjects had significantly more dementia than non-diabetic subjects (χ² = 7.54, df = 1, p = 0.006, OR 2.83 [95% CI = 1.40 to 5.71]). Those who survived to the time of this study were younger and healthier than those who died. Conclusions: Evidence for diabetes as a risk factor for dementia was found, similar to other epidemiologic studies. In contrast to the earlier studies, however, the authors linked diabetes in midlife to dementia more than three decades later in the very old survivors of a large male cohort.