Université de Sherbrooke and Canadian collaborators report an association between long-term residential sulfur dioxide exposure and higher odds of amyotrophic lateral sclerosis (ALS) onset.
ALS is a rare motor neuron disease with limited therapeutic options and substantial mortality within a few years of symptom onset. Previous environmental work has linked air pollution to respiratory illness and neurodegeneration, with some studies examining fine particulates and nitrogen dioxide (NO2) in relation to ALS.
Sulfur dioxide is emitted primarily through the burning of fossil fuels, released into the air during the combustion of coal and oil in power plants as well as diesel-powered vehicles. Investigation into sulfur dioxide’s potential ALS role has been sparse, and identification of confounders such as ozone (O3) and particulate matter (PM) has been lacking.
In the study, “Associations between long-term air pollution exposure and the development of amyotrophic lateral sclerosis: A matched case-control study,” published in Environmental Research, researchers conducted a matched case-control study to test whether long-term exposure to common ambient pollutants relates to ALS onset.
Study enrollment drew from a provincial ALS clinic in New Brunswick, Canada, yielding 304 ALS cases and 1,207 sex- and birth-year-matched controls after applying inclusion criteria.
Exposure histories came from postal-code linked estimates for NO2, O3, PM2.5, PM2.5 (smoke), and SO2. Conditional logistic regression modeled associations with onset standardized to two years before diagnosis.
Results showed higher median residential SO2 among cases than controls with a significant P value of 0.024. Adjusted direct-effect models indicated increased odds of ALS per interquartile rise in SO2 of 0.14 parts per billion (ppb) with an odds ratio (OR) of 1.23.
NO2, O3, PM2.5, and smoke were not significantly associated in adjusted models, including NO2 with OR 1.15, O3 with OR 0.98, PM2.5 with OR 0.99, and smoke with OR 1.05. SO2 remained associated in a model that included NO2 with OR 1.23.
Models that only considered the five-year and 10-year windows before onset also showed associations for SO2 with OR 1.21 and with OR 1.23.
Authors conclude that residential SO2 exposure relates to ALS development in residential air and call for strengthened air-pollution control strategies.
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More information:
Daniel Saucier et al, Associations between long-term air pollution exposure and the development of amyotrophic lateral sclerosis: A matched case-control study, Environmental Research (2025). DOI: 10.1016/j.envres.2025.122232
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Residential sulfur dioxide exposure linked to higher odds of amyotrophic lateral sclerosis onset (2025, September 30)
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