Long-term exposure to air pollution increases risk of autoimmune disease

Research published in the online edition of the open-access journal RMD open found that long-term exposure to air pollution was associated with an increased risk of autoimmune diseases, particularly rheumatoid arthritis, connective tissue and inflammatory bowel disease

Ambient air pollution from car exhaust and industrial output can trigger adaptive immunity, where the body responds to specific disease-causing entities

Examples of autoimmune diseases include rheumatoid arthritis; systemic lupus erythematosus; inflammatory bowel diseases, such as ulcerative colitis; connective tissue diseases, such as osteoarthritis; and multiple sclerosis

The incidence and prevalence of these diseases have steadily increased over the past decade for reasons that are not fully understood

To shed light on these questions, the researchers mined the Italian National Fracture Risk Database (DeFRA) and retrieved comprehensive medical information for 81,363 men and women submitted by more than 3,500 physicians between June 2016 and November 2020

The majority were women (92%), the mean age was 65 years, and 17,866 (22%) had at least one coexisting health condition

Each participant was linked by their residential postcode to the nearest air quality monitoring station, operated by the Italian Agency for Environmental Protection and Research

The researchers were particularly interested in the potential effects of particulate matter (PM10 and PM2.

Between 2016 and 2020, about 9,723 people (12%) were diagnosed with an autoimmune disease

Information on air quality comes from 617 monitoring stations in 110 Italian provinces

Exposure to PM2.

Long-term exposure to PM10 above 30 μg/m3 and PM2.

Long-term exposure to PM10 was specifically associated with an increased risk of rheumatoid arthritis, while long-term exposure to PM2.

Overall, long-term exposure to traffic and industrial air pollutants was associated with an approximately 40% increased risk of rheumatoid arthritis, a 20% increased risk of inflammatory bowel disease, and a 15% increased risk of connective tissue disease

This is an observational study and cannot establish cause

These include: a lack of information on the date of diagnosis and onset of autoimmune disease symptoms; air quality monitoring may not reflect an individual's exposure to pollutants; and the findings may not apply to the wider population because study participants Mostly older women at risk for fractures

But they explain that air pollution has been linked to immune system abnormalities, and that smoking, along with certain toxins emitted by fossil fuels, is a predisposing factor for rheumatoid arthritis
.