Air pollution may increase autoimmune risk through ANA positivity

A Canadian analysis showed that higher long-term exposure to fine particulate matter (PM2.5) correlates with increased antinuclear antibody (ANA) positivity. This finding reinforces that air pollution may serve as an environmental trigger for autoimmune responses.

Environmental factors relevant to systemic autoimmune rheumatic diseases (SARDs) are increasingly being recognised, but direct serological associations have remained limited until now. In the Ontario Health Study, 1 of Canada’s largest population health databases, Dr Sasha Bernatsky (Research Institute of the McGill University Health Centre, Canada) and colleagues explored the relationship between PM2.5 exposure and ANA positivity, a recognised biomarker of SARDs [1].

The researchers analysed data from 3,548 randomly selected serum samples collected between 2010–2013. ANA titres were determined by indirect immunofluorescence, and 5-year average ambient PM2.5 levels were assigned to participants using residential postal codes. Multivariable logistic regression models were adjusted for age, sex, ethnicity, smoking status, and the Rurality Index of Ontario.

While lower ANA titres (≥1:160 or ≥1:320) showed no statistically significant association with PM2.5, higher titres revealed an exposure-response relationship. Individuals in the highest quartile of PM2.5 exposure had an adjusted odds ratio (aOR) of 1.67 (95% CI 0.99–2.82) for titres ≥1:640 and an aOR of 2.33 (95% CI 1.11–4.91) for titres ≥1:1280, indicating more than a 2-fold increased likelihood of high-titre ANA positivity.

These findings support the hypothesis that sustained exposure to airborne pollutants can disrupt immune regulation, potentially triggering or exacerbating autoimmune responses. The effect was particularly notable at the highest ANA titres, highlighting the need for environmental considerations in autoimmunity research and prevention strategies.

According to the authors, this analysis underscores the immune-disruptive effects of air pollution and its potential link to the development of autoimmune diseases.

1. Zhao N, et Fine particulate matter air pollution and anti-nuclear antibody positivity: the Ontario Health Study. POS0101, EULAR 2025, 11–14 June, Barcelona, Spain.

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Posted on 8 August 20258 August 2025