Poor air quality from sources like wildfires, vehicle emissions, and factories can damage lung health, but growing evidence suggests it might also raise the risk of developing autoimmune diseases. A study published this summer in Arthritis & Rheumatology indicated that long-term air pollution exposure may trigger lupus, a chronic autoimmune disease.
Approximately 40% of Americans, or over 130 million people, live in areas with unhealthy air pollution levels, according to the latest “State of the Air” report by the American Lung Association, which is an increase of nearly 12 million from last year’s report.
In the U.S., around 50 million people have an autoimmune disease, and the number of these conditions is rising each year. While the exact causes of autoimmune diseases, such as systemic lupus erythematosus (SLE) and rheumatoid arthritis, remain somewhat of a mystery, experts believe that genetics and environmental exposure, including air pollution, may work together to trigger these diseases. Some evidence suggests that in conditions like arthritis, air pollution might be a significant contributing factor, though not the sole one.
Research over the past decade has pointed out the connection between air pollution and autoimmune diseases. Prior studies found that air pollution might disrupt the immune system, lead to systemic inflammation, and alter cells, potentially explaining its link to autoimmune diseases.
A study from 2022 led by Giovanni Adami and his team showed that exposure to poor air quality correlated with a higher risk of rheumatoid arthritis, inflammatory bowel disease, and connective tissue disorders, including lupus. Building on these findings, the recent study from Huazhong University of Science and Technology focused specifically on the link between SLE and air pollution. Researchers analyzed data from nearly 460,000 people in the U.K. Biobank, measuring their exposure to nitrogen dioxide, nitrogen oxides, and fine particulate matter. Over an average follow-up period of nearly 12 years, about 400 participants were diagnosed with SLE.
The study found that those exposed to air pollution were 13% to 27% more likely to develop SLE. Individuals with both a genetic predisposition and high exposure had the highest risk, with a 316% to 461% greater chance of developing SLE compared to those with low genetic risk factors and low pollution exposure. However, air pollution exposure alone doesn’t determine the onset of SLE or any other autoimmune disease—existing genetic risks usually play a role.
Genetic factors are crucial in triggering most diseases, including SLE. Even if lupus isn’t present in a family’s history, an individual might still have genetic risk factors for the disease. Moreover, gender might play a part, as biological women account for about 90% of lupus cases, leading experts to consider estrogen or X chromosome genes in the disease’s development.
Environmental toxins, like air pollution, cigarette smoke, and certain viral infections, can act as a tipping point for those with specific genetic risks, potentially leading to autoimmune diseases. Most people have some genetic immune factors that could put them at risk for conditions like SLE or rheumatoid arthritis. These factors are usually minor contributors, but a combination of environmental exposures can eventually lead to the development of these diseases.
Experts are still figuring out what exactly causes lupus. It is believed that for lupus developing later in life, genetic factors might be worsened by environmental factors until a trigger, such as a viral infection, stimulates the immune system enough to cause the disease spectrum known as SLE.
Not all air pollution is equally harmful. Smaller particles, 10 micrometers or smaller, can penetrate deeper into the body, potentially causing greater harm. Ammonium, a fertilizer chemical, has raised concerns about its potential to trigger rheumatoid arthritis.
Understanding how different air pollution types impact autoimmune diseases could inform policies to reduce exposure. Stricter air quality regulations, particularly as climate change increases air pollution levels and the frequency of wildfire smoke, could mitigate these risks. Yaohua Tian, a study author, highlighted that such findings are vital for developing air quality regulations to lower the risk of lupus.
It’s not always easy for individuals to avoid unhealthy air, especially for low-income and BIPOC communities living in areas with high pollution levels. However, taking certain precautions can help reduce exposure. For people working in mines, with asphalt, or on roadsides, wearing masks at work can protect against excessive air pollution, offering significant benefits, according to Adami.
