Air Pollution Linked to Elevated Risk of RA and RA-Associated Interstitial Lung Disease

According to a study published in Arthritis & Rheumatology, exposure to certain environmental pollutants may play a role in the development of rheumatoid arthritis (RA) and RA-associated interstitial lung disease (RA-ILD), according to findings from a recent Veterans Affairs (VA) study analyzing a decade’s worth of patient data.

In this patient-control study spanning from 2009 to 2018, researchers assessed air pollutant exposure–particularly particulate matter smaller than 2.5 μm (PM2.5) related to fire smoke—and its association with new cases of RA and RA-ILD among VA patients. The cohort included 9701 patients with incident RA (mean age 65 years, 86% male), of whom 531 also had RA-ILD. These were matched to 68,852 controls on age, sex, and enrollment year.

While fire smoke-related PM2.5 was not associated with increased risk for RA overall (adjusted odds ratio [aOR] 1.07; 95% CI, 0.92–1.23), it was significantly associated with nearly double the odds of developing RA-ILD (aOR 1.98; 95% CI, 1.08–3.62, per 1 μg/m³ increase in exposure). The association between air pollution and pulmonary complications in patients with RA underscores a need for greater awareness of environmental risk factors in clinical care.

Additional pollutants were also linked to RA risk. Higher exposure to nitrogen oxides (NOx) was associated with increased risk of RA (aOR 1.16; 95% CI, 1.06–1.27), while ozone (aOR 1.19; 95% CI, 1.06–1.34) and PM10 (aOR 1.25; 95% CI, 1.10–1.43) were associated with seronegative RA. In contrast, exposure to carbon monoxide, overall PM2.5, and sulfur dioxide (SO2) showed no positive association or were negatively associated with RA or RA-ILD.

“These findings suggest that specific pollutants, particularly NOx, ozone, PM10, and fire-related PM2.5, may be linked to increased risk for RA and RA-ILD,” the authors stated. “Given the systemic and pulmonary manifestations of RA, environmental exposures warrant closer consideration in both clinical management and public health interventions.”

The results support growing evidence of air pollution as a modifiable risk factor in autoimmune and rheumatic diseases. For rheumatologists, integrating environmental exposure history into risk assessment may be particularly valuable in patients with pulmonary symptoms or high-risk occupational or geographic profiles.

Reference
Kronzer VL, Yang Y, Roul P, et al. Associations of fire smoke and other pollutants with incident rheumatoid arthritis and rheumatoid arthritis-associated interstitial lung disease. Arthritis Rheumatol. Published online January 12, 2025. doi:10.1002/art.43113