Background: The role of DM as a risk factor for cognitive decline in later life has received little epidemiological attention until recently. This is despite the high prevalence of diabetes (especially type 2) in older populations. Objective: To compare between the risk of development of Alzheimer disease (AD) in patients with and without non-insulin dependent diabetes mellitus (NIDDM). Methods: This study is a longitudinal cohort study. For up to 2 years, 764 subjects underwent annual evaluation that included medical history, neurological examination, neuropsychological performance testing, and review of a brain scan when available. For a diagnosis of probable Alzheimer's disease, the criteria adapted from the National Institute of Neurological and Communicative Disorders and Stroke and Alzheimer’s disease and Related Disorders Association (NINCDS-ADRDA). Results: Diabetes mellitus was present in 106 (13.9%) of the participants. During a mean of 2 years of observation, 137 persons developed AD. In a proportional hazards model adjusted for age, sex, and educational level, those with diabetes mellitus had a 61% increase in the risk of developing AD compared with those without diabetes mellitus (hazard ratio, 1.53; 95% confidence interval, 0.96-2.45). The risk of incident dementia was clearly modified by baseline treatment), with the lowest relative risk in newly discovered or untreated diabetic patients (RR 1.3, 95% CI 0.7 to 2.3) and the highest RR among patients treated with insulin (RR 4.3, 95% CI 1.7 to 10.5). Conclusion: Patients with NIDDM; particularly those treated with insulin may be at an increased risk of developing AD. [Egypt J Neurol Psychiat Neurosurg. 2010; 47(3): 419-424]
Key Words: Alzheimer's disease, NIDDM.