Association of cigarette smoking with amyotrophic lateral sclerosis

We explored the relationship between amyotrophic lateral sclerosis (ALS) an d cigarette smoking in a case-control study conducted in New England from 1 993 to 1996. Recently diagnosed ALS cases (n = 109) were recruited from two major referral centers. Population controls (n = 256) were identified by r andom telephone screening. Data were analyzed by logistic regression. After adjusting for age, sex, region and education, ever having smoked cigarette s was associated with an increase in risk for ALS (odds ratio 1.7; 95% conf idence interval 1.0-2.8). Average cigarettes smoked per day, years smoked a nd pack-years were all greater in cases than controls, but dose-response tr ends were not observed. Similar numbers of cases and controls had ever used alcohol, and only a small, nonsignificant association of drinks per month with ALS was observed. The association of cigarette smoking with ALS was no t affected by adjusting for alcohol use. In contrast, the weak relationship of ALS with alcohol use was apparently due to confounding by smoking.