Air Pollution Associated with Motor Neuron Disease Incidence and Disease Progression

Long-term exposure to ambient air pollution may increase both the risk of motor neuron disease (MND)—including amyotrophic lateral sclerosis (ALS)—as well as the speed of disease progression, according to a nationwide Swedish study published in JAMA Neurology. Even at the relatively low pollution levels typical in Sweden, the investigators linked particulate matter (PM) and nitrogen dioxide (NO₂) exposure with incident MND, higher risk of death or invasive ventilation, and faster decline in motor and respiratory function, pointing to air quality as a potentially modifiable neurologic factor.

The population-based nested case-control study included an analysis of Swedish registry data for 1463 people with newly diagnosed MND between 2015 and 2023, along with 7310 age- and sex-matched population controls and 1768 sibling controls. Researchers estimated 1-, 3-, 5-, and 10-year average residential exposure to NO₂ and PMs of 2.5 μm or less, 2.5 to 10 μm, and 10 μm or less (PM_2.5, PM_2.5-10, PM₁₀) using validated spatiotemporal models, then assessed associations with MND diagnosis, mortality or invasive ventilation after diagnosis, and risk of rapid functional decline based on ALS Functional Rating Scale–Revised (ALSFRS-R) scores.

Key Findings

• In the population comparison, each interquartile-range increase in 10-year exposure was associated with higher odds of MND: PM_2.5 (odds ratio [OR], 1.21; 95% CI, 1.09 to 1.34), PM_2.5-10 (OR, 1.30; 95% CI, 1.19 to 1.42), PM₁₀ (OR, 1.29; 95% CI, 1.18 to 1.42), and NO2 (OR, 1.20; 95% CI, 1.12 to 1.29).
• The sibling analysis showed similar associations with 10-year exposure: PM_2.5 (OR, 1.22; 95% CI, 1.02 to 1.47), PM_2.5-10 (OR, 1.15; 95% CI, 1.00 to 1.33), PM₁₀ (OR, 1.20; 95% CI, 1.04 to 1.39), and NO₂ (OR, 1.12; 95% CI, 1.00 to 1.26).
• Higher PM₁₀ and NO₂ exposure was associated with greater hazard of death or invasive ventilation after diagnosis, with the largest effect seen for 1-year PM₁₀ exposure (hazard ratio [HR], 1.30; 95% CI, 1.12 to 1.50) and 1-year NO₂ exposure (HR, 1.23; 95% CI, 1.10 to 1.36).
• Higher particulate exposure was also tied to faster functional decline, including worse total ALSFRS-R progression and stronger signals for motor and respiratory deterioration, while bulbar decline was not clearly associated.

Source

Wu J, Pyko A, Chourpiliadis C, et al. Long-term exposure to air pollution and risk and prognosis of motor neuron disease. JAMA Neurol. 2026;83(3):213-222. doi:10.1001/jamaneurol.2025.5379