Inhaled substances such as tobacco smoke have previously been linked both to risk for rheumatoid arthritis (RA) and to its exacerbations.The degree to which environmental air pollutants may worsen existing RA, however, has not been examined in detail before.In this study from Korea, levels of small particulate matter correlated with increased RA disease activity and risk for disease flares.
Koreans with rheumatoid arthritis (RA) showed increased disease activity and higher flare rates when exposed to relatively high levels of small atmospheric particulate matter, researchers reported.
Each 6-μg/m3 increment in particles ≤2.5 μm (PM2.5) was associated with an 11% increase in odds for developing an RA flare (OR 1.113, 95% CI 1.017-1.218), according to Eun Bong Lee, MD, PhD, of Seoul National University College of Medicine in South Korea, and colleagues.
As well, each 10-μg/m3 increment in PM2.5 came with a statistically significant 0.052-point increase in 28-joint Disease Activity Score (DAS28) values, the group reported in Annals of the Rheumatic Diseases.
Some other air pollutants also showed similar trends, including particles smaller than 10 μm (PM10), nitrogen oxides, and ozone, which did not achieve statistical significance. Curiously, though, a negative (but not significant) association was seen between carbon monoxide levels and flare risk (OR 0.917 per 1 standard deviation [SD], P=0.092).
