Air Pollution Linked to Increased Rheumatoid Arthritis Activity and Flares: Study
Researchers have found in a new study that exposure to high levels of fine particulate air pollution (PM) was associated with increased disease activity and a higher risk of flares in patients with rheumatoid arthritis (RA). The findings suggest that environmental air pollution, like tobacco smoke, may worsen RA and should be considered a modifiable factor in disease management. The study was published in the Annals of the Rheumatic Diseases by Sung C. and colleagues.
The association of atmospheric pollution and joint inflammation was studied using a prospective cohort study design where 1,070 patients with rheumatoid arthritis, admitted during the period from January 2021 to December 2024, participated. Environmental exposure levels were measured based on average monthly concentrations of six primary pollutants present in ambient air like sulfur dioxide, nitrogen dioxide, ozone, carbon monoxide, particulate matter (PM10, PM2.5).
The clinical outcome and joint count measures and acute disease exacerbation were measured over 12,583 visits using generalized estimating equation. Furthermore, the sensitivity analysis of within patient case-crossover analysis was carried out using conditional logistic regression.
Key findings:
- The analytical dataset consisted of 12,583 total outpatient clinical evaluations obtained from 1,070 individual patients with diagnosed rheumatoid arthritis.
- The six pollutants that were examined included PM2.5, which showed statistically significant correlation with increased risk of flaring disease (adjusted odds ratio [aOR], 1.113; 95% CI, 1.017–1.218).
- Increased concentration levels of PM2.5 were positively correlated with higher Disease Activity Score based on 28 joints and calculated using C-reactive protein (DAS28-CRP), Clinical Disease Activity Index, count of 28 tender joints, and 28 swollen joints.
- Case crossover studies showed that long position of elevated PM2.5 exposure exceeding 2 weeks significantly increased the risk of acute rheumatoid arthritis flare.
- Overall, the statistical relationship between fine particulate exposure and increased DAS28-CRP was more pronounced among female patients and non-smoking individuals.
Overall, air pollution exposure, especially PM2.5, had an association with disease activity and disease flare among individuals with RA. Additional research is needed to understand the impact of bettering air quality on reducing disease activity among those with RA. It is essential for both medical professionals and environmental policymakers to understand that air pollution is a modifiable risk factor for autoimmune disease, including protection of joint health.
Reference:
Jung, S. C., Curtis, J. R., Yang, S., Choi, Y., Lim, M. H., Lee, S., Cho, S. I., Park, J. K., Park, J. W., & Lee, E. B. (2026). Effects of air pollution on disease activity in patients with rheumatoid arthritis. Annals of the Rheumatic Diseases. https://doi.org/10.1016/j.ard.2026.06.018
