Exposure to air pollution, particularly tiny particles from dust, soot and smoke, may increase disease activity and trigger flare-ups in people living with rheumatoid arthritis (RA), according to new research.
The study, published in Annals of the Rheumatic Diseases, found that higher levels of PM2.5 were associated with worsening symptoms in people who already had RA. Researchers say the findings highlight the importance of considering environmental factors as part of long-term disease management.
RA is a chronic autoimmune condition in which the body’s immune system mistakenly attacks healthy tissue, causing inflammation, pain and damage in the joints. It can also affect other parts of the body, leading to wider symptoms beyond joint problems.
The condition affects around 0.5% to 1% of adults worldwide, and its development is influenced by a combination of genetic, immune and environmental factors. Smoking is already recognised as a major risk factor, while other environmental exposures, including certain pollutants, have also been linked to the disease.
Previous studies have suggested that air pollution may increase the risk of developing RA. However, researchers wanted to understand whether pollution could also influence how active the disease becomes in people who already have the condition.
A team of investigators in South Korea followed 1,070 patients with RA over four years, analysing data from more than 12,500 outpatient visits between 2021 and 2024. They compared patients’ disease activity and flare-ups with estimated exposure to six common air pollutants, including PM2.5, PM10, nitrogen dioxide, ozone, sulphur dioxide and carbon monoxide.
After taking into account factors such as age, sex, medication use, socioeconomic conditions, weather and disease characteristics, the researchers identified PM2.5 as the strongest contributor to increased RA activity.
The researchers suggest that these particles may contribute to inflammation by increasing the production of reactive oxygen species — unstable molecules that can cause cellular stress, damage DNA and activate inflammatory responses.
Lead investigator Eun Bong Lee said: ‘Our study has important implications for public health policy making. While further studies are warranted to determine whether improving air quality can reduce disease activity in RA patients, we would recommend these patients avoid prolonged exposure to poor air quality, particularly high PM2.5 levels.’
The full research can be read here.
Photo: roger vaughan
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