Lifetime occupation, education, smoking, and risk of ALS

To investigate the association between cigarette smoking, level of education, occupation, and the occurrence of sporadic amyotrophic lateral sclerosis (ALS). A total of 364 patients and 392 controls completed a questionnaire covering smoking habits, level of education, and occupational history. Main occupations were coded according to the International Standard Classification of Occupations and compared between patients and controls. The univariate analysis showed an increased risk of developing ALS among current cigarette smokers (OR = 1.7; 95% CI = 1.1 to 2.6; p = 0.01), those with a low level of education (elementary school) (OR = 2.2; 95% CI = 1.2 to 3.8; p < 0.01), and among women whose main occupation was classified as crafts and related trades workers (OR = 8.4; 95% CI = 1.0 to 70.1; p = 0.05). Multivariate analysis (with covariates age, smoking, education, and occupation) showed an increased risk for current smokers of cigarettes (OR = 1.6; 95% CI = 1.0 to 2.5; p = 0.04). Occupation, education, and cigarette smoking are risk factors for amyotrophic lateral sclerosis, but only smoking appeared independently associated.