Amyotrophic lateral sclerosis and exposure to diesel exhaust in a Danish cohort

Abstract

Previous studies have suggested an increased risk of amyotrophic lateral sclerosis (ALS) and other motor neuron diseases for those in occupations commonly exposed to diesel exhaust (DE). In this study, we investigated the association between occupational exposures to DE and odds of ALS. ALS cases were identified from the Danish National Patient Registry 1982 to 2013 and individually matched to 100 controls per case based on birth year and sex. Using occupational history since 1964 from the Danish Pension Fund, Cumulative DE exposures were estimated using a job exposure matrix. Associations were evaluated using conditional logistic regression analyses and stratified by sex. DE exposure at 10-year lag periods was positively associated with ALS in men ever exposed (aOR: 1.20; 95% CI: 1.05, 1.38). For men with > 50% probability of DE exposure, we observed a positive association with ALS and the highest quartile exposures during the 5-year lag period (aOR: 1.40; 95% CI: 1.11, 1.78) and 10-year lag period (aOR: 1.41; 95% CI: 1.11, 1.79). Our study suggests an association between consistently higher exposures to DE and ALS in men but not in women. These findings support those of previously reported associations between ALS and commonly DE exposed occupations.