A new study by the University of Verona and presented at the 2022 Congress of the European Alliance of Associations of Rheumatology (EULAR) examined the association between long-term exposure to air pollution and immune-mediated diseases such as rheumatoid arthritis (RA) or inflammatory bowel disease (IBD). Experts have found that people exposed to high levels of air pollution for a long time have a significantly higher risk of developing autoimmune diseases.
Particulate matter (PM) is a mixture of solid and liquid particles in the air, consisting of various chemicals and materials, some of which are highly toxic (in particular, the so-called PM10 and PM2.5). After analyzing data from more than 80,000 people in Italy, scientists found a positive relationship between PM levels measured at local air quality stations and the risk of developing autoimmune diseases.
The results showed that exposure to PM10 above 30 µg/m³ and PM2.5 above 20 µg/m³ was associated with a 12 and 13 percent increased risk of developing autoimmune diseases. If exposure to PM10 was associated with an increased risk of developing RA but not other autoimmune diseases, then exposure to high levels of PM2.5 led to an increased risk of developing both RA and IBD. Overall, chronic exposure to particulate matter has been associated with a 10 percent increased risk of developing immune-mediated diseases.
The same research team studied the association between long-term PM exposure and osteoporosis – which, while not an autoimmune disease, appears to be caused by a malfunctioning immune system – in a cohort of 60,000 women at high risk of fracture. They found that chronic exposures greater than 25µg/m³ for PM2.5 and 30µg/m³ for PM10 were associated with a 16% and 15% increased risk of osteoporotic bone mass at any site.
A related study found that one of the main causes of RA is exposure to crystalline silica, a substance released during cleaning, which includes handling dusty clothes or talc. These results suggest that housekeeping is an underestimated source of silica exposure, which is more present in women with RA compared to the general population and may be a significant contributor to the pathogenesis of the disease.
Further research is needed to clarify the links between air pollution and immune-mediated diseases, and to properly map the complex relationships between environmental factors, gender, occupation, and disease risk.