The Canadian Study of Health and Aging: risk factors for Alzheimer's disease in Canada.

OBJECTIVE: To study risk factors for Alzheimer's disease (AD) based on data from the Canadian Study of Health and Aging. DESIGN: Population-based case-control study. SETTING: Communities and institutions in 10 Canadian provinces. PARTICIPANTS: Two hundred fifty-eight cases clinically diagnosed with probable AD, with onset of symptoms within 3 years of diagnosis, and 535 controls, frequency matched on age group, study center, and residence in community or institution, clinically confirmed to be cognitively normal. MAIN OUTCOME MEASURE: Odds ratios (ORs) were calculated using unconditional logistic regression for previously hypothesized and potential risk factors for AD. RESULTS: The OR for family history of dementia was significantly elevated (2.62; 95% confidence interval [CI], 1.53 to 4.51) and increased with the number of relatives with dementia. Those with less education were at higher risk of AD, with an OR of 4.00 (95% CI, 2.49 to 6.43) for those with 0 to 6 years, in comparison with those with 10 or more years. Head injury achieved borderline significance. A history of arthritis resulted in a low risk of AD (OR = 0.54; 95% CI, 0.36 to 0.81), as did a history of use of nonsteroidal anti-inflammatory drugs. Initial analyses showed an increased risk of AD for occupational exposure to glues as well as to pesticides and fertilizers; the increased risk was greater in those with less education. CONCLUSION: This study confirmed a number of previously reported risk factors for AD, but provided little support for others. A new finding was an increased risk for those with occupational exposure to glues as well as pesticides and fertilizers, but this needs further study.

Duke Scholars

Author Truls Ostbye Family Medicine and Community Health