A Case-Control Study of Smoking and Alzheimer's Disease

Objectives. To study the association between Alzheimer's disease and smoking history. Design. An unmatched case-control study. Setting. Psychogeriatric unit serving an elderly population of Warrington. Period. 2 years 1991–1993. Subjects. 198 cases of Alzheimer's disease (ADRDA–NINCDS diagnostic criteria) were compared to two selected control groups (164 other dementias and 176 non-dementing group) with respect to their smoking history. Main outcome measure. Relative risk (odds ratio) of Alzheimer's disease. Results. The odds ratio for Alzheimer's disease in patients who smoked was 0.68 (95% CI 0.47–0.98). The negative association was statistically significant only in male patients, OR 0.45 95% CI (0.23–0.87), p<0.05. The inverse association was also only significant in patients with family history of dementia, OR 0.34 95% CI (0.12–0.92), p<0.05. Conclusion. The study supports previous findings of an inverse relationship between smoking and Alzheimer's disease. This, however, does not suggest that smoking is used as a preventive measure for Alzheimer's disease.