Relation of smoking and alcohol consumption to incident Alzheimer's disease.

The authors examined the effects of smoking and alcohol use in a prospective community-based study of incident Alzheimer's disease. Two in-home interviews of the total elderly population of East Boston, Massachusetts, conducted in 1982 and 1985 were used to sample individuals for clinical evaluation for Alzheimer's disease. A total of 513 persons underwent detailed clinical evaluation including neurologic, neuropsychologic, and psychiatric evaluation to diagnose Alzheimer's disease. In weighted logistic regression controlled for age, sex, and education, the estimated odds ratio of Alzheimer's disease was 0.7 (95% confidence interval 0.3-1.4) for ever smokers compared with never smokers. For 40 pack-years of smoking, the odds ratio of Alzheimer's disease was 0.8 (95% confidence interval 0.6-1.1). Consumption of 1 oz (30 ml) of alcohol per day was associated with an odds ratio of 1.1 (95% confidence interval 0.8-1.5). These results suggest that recent mild-to-moderate consumption of alcohol is not substantially related to incidence of Alzheimer's disease and that smoking does not increase risk of the disease.