Lifetime occupation, education, smoking, and risk of ALS

Objective: To investigate the association between cigarette smoking, level of education, occupation, and the occurrence of sporadic amyotrophic lateral sclerosis ( ALS). Methods: 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. Results: 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). Conclusions: Occupation, education, and cigarette smoking are risk factors for amyotrophic lateral sclerosis, but only smoking appeared independently associated.