LONG-TERM exposure to air pollution is associated with both an increased risk of developing motor neuron disease (MND) and worse outcomes after diagnosis, according to a large population-based study from Sweden. The findings suggest that air pollution may play a role not only in disease onset but also in accelerating disease progression and mortality.
Investigating Environmental Risk Factors for Motor Neuron Disease
While air pollution has been linked to other neurodegenerative diseases, evidence for its role in MND has remained sparse, particularly regarding disease prognosis.
To address this gap, researchers conducted a nationwide nested case-control study using Swedish health registry data. The study included patients newly diagnosed with MND between 2015 and 2023, along with matched population controls and sibling controls to account for shared genetic and environmental factors. Long-term exposure to particulate matter and nitrogen dioxide was estimated at participants’ residential addresses over exposure windows of up to 10 years prior to diagnosis.
Consistent Associations with Disease Risk and Progression
The study included 1,463 patients with MND, 7,310 population controls, and 1,768 sibling controls. Higher long-term exposure to fine and coarse particulate matter (PM2.5, PM2.5–10, and PM10) and nitrogen dioxide (NO₂) was consistently associated with an increased risk of MND. The strongest associations were observed for 10-year average exposure, highlighting the importance of cumulative air pollution exposure.
Among individuals diagnosed with MND, higher levels of PM10 and NO₂ were associated with increased mortality and a greater likelihood of requiring invasive ventilation. In addition, higher exposure to all particulate matter measures was linked to faster functional decline, particularly affecting motor and respiratory function, as measured by the ALS Functional Rating Scale–Revised.
Implications For Public Health and Disease Prevention
These findings indicate that air pollution, even at relatively low levels typical of high-income countries, may contribute to both the development and progression of motor neuron disease. The results strengthen the evidence that environmental exposures are relevant in neurodegenerative disease risk and prognosis.
From a public health perspective, reducing long-term exposure to air pollution could represent a modifiable strategy to lower the burden of MND and potentially slow disease progression after diagnosis. The study also highlights the need for future research exploring interactions between genetic susceptibility and environmental pollutants to better understand individual risk profiles.
Reference
Wu J et al. Long-term exposure to air pollution and risk and prognosis of motor neuron disease. JAMA Neurol. 2026;DOI:10.1001/jamaneurol.2025.5379.
