Diabetes mellitus, apolipoprotein E and dementia: Results from the Canadian Study of Health and Aging

Introduction: We have previously found that diabetes is related to vascular cognitive impairment, though not to Alzheimer's disease. We now report the effect of apolipoprotein E on this relationship. Method: Data is from the Canadian Study of Health and Aging. Apolipoprotein E results were available on 1183 subjects, of whom 134 were diabetic. Incident dementia was diagnosed by consensus conference after a comprehensive evaluation. We classified dementia as Alzheimer's disease, vascular cognitive impairment or other. Results: There were 162 subjects with incident Alzheimer's disease and 137 with incident vascular cognitive impairment. Diabetes was not related to incident dementia, with no effect modification from ApoE (OR 1.07, 95% CI 0.68-1.69). Results were similar for incident Alzheimer's disease (OR 0.99, 95%CI 0.57-1.73). Odds ratios for incident vascular cognitive impairment were significant, and unchanged by the addition of ApoE to the model (OR 1.88, 95% CI 1.16-3.06 and OR 1.86, 95% CI 1.14-3.04). Conclusion: Diabetes is a risk factor for vascular cognitive impairment, though not for Alzheimer's disease, with no effect modification from apolipoprotein E.