Increased air pollution has been linked with rise in risk of autoimmune diseases, according to a twin study.
Two abstracts presented by Dr Giovanni Adami at the 2022 EULAR Congress looked at the issue of environmental exposures and their role in disease development.
Particulate matter (PM) is defined as everything in the air that is not a gas, and includes a variety of chemicals and materials, some of which can be toxic.
Data from over 80,000 people in a retrospective observational study in Italy found a positive association between PM levels measured at local air-quality stations and the risk of autoimmune diseases.
In fact, every 10 micrograms per cubic metre increase in PM10 concentration was associated with an incremental 7 per cent risk of having autoimmune disease.
Exposure to PM10 above 30 micrograms per cubic metre and PM2.5 above 20 micrograms per cubic metre was associated with 12 per cent and 13 per cent higher risks of autoimmune disease, respectively.
When broken down by individual diseases, exposure to PM10 was associated with an increased risk of rheumatoid arthritis (RA) but no other autoimmune diseases, whereas exposure to high levels of PM2.5 was associated with an increased risk of RA and inflammatory bowel disease.
Overall, chronic exposure to particulate air pollution above the threshold for human protection was associated with a 10 per cent higher risk of developing immune-mediated diseases.
In a separate study, the same team looked at the association between long-term exposure to PM and osteoporosis in almost 60,000 women at high risk of fracture.
The results showed that exposure to PM2.5 was negatively associated with low bone mass at the top of the thigh bone and lumbar spine.
Chronic exposure above 25 micrograms per cubic metre for PM2.5 and 30 micrograms per cubic metre for PM10 was associated with a 16 per cent and 15 per cent higher risk of having osteoporotic bone mass scores at any site.
The researchers concluded that long-term exposure to air pollution was associated with higher risk of osteoporosis.
Further, among the RA patients, high silica exposure was independently associated with lung abnormalities such as interstitial lung disease and mediastinal lymphadenopathy.