The study primarily focused on fire smoke as the main pollutant, while also considering secondary pollutants such as carbon monoxide, nitrogen oxides, sulfur dioxide, ozone, and PM10.

The study utilized a case-control design, analyzing data from 9,701 RA patients and 68,851 matched controls from the US Veterans Affairs dataset, covering the period from October 2009 to December 2018.

However, the study faced limitations such as selection bias due to missing data for controls, overrepresentation of men and smokers, potential misclassification of pollutant exposure, and an inability to assess various confounding factors.

This research received support from multiple organizations, including Veterans Affairs and the National Institutes of Health, with some authors disclosing research support from pharmaceutical companies.

Greater exposure to fire smoke containing particulate matter smaller than 2.5 microns (PM2.5) is linked to a higher risk of developing RA and RA-ILD in future years.

The authors of the study advocate for controlling air pollutants and conducting targeted screenings for at-risk populations to improve health outcomes.

A recent study led by Dr. Vanessa L. Kronzer from the Mayo Clinic, published in Arthritis & Rheumatology, highlights the significant health risks associated with fire smoke exposure.

The research found that exposure to fire smoke nearly doubled the risk of developing rheumatoid arthritis-associated interstitial lung disease (RA-ILD), particularly at concentrations of 0.28 µg/m3 or higher, with an adjusted odds ratio of 1.98.

While overall rheumatoid arthritis (RA) was not directly linked to fire smoke exposure, there was a notable increase in risk for those exposed within 1-3 years and 3-5 years prior to diagnosis, showing a 12% and 13% increased risk per 1 µg/m3 increase in PM2.5, respectively.

Additionally, elevated levels of nitrogen oxides were associated with a 16% increased risk for RA, and the highest quartiles of ozone and PM10 exposure were linked to seronegative RA.

Data on exposure were collected over one year following Veterans Affairs enrollment, with a mean age of 65 years for RA patients and 69 years for those with RA-ILD.