Air pollution resulting predominantly from industrial production and vehicle exhaust is among the environmental factors linked to the development of immune-mediated diseases. The incidence and prevalence of these diseases have been increasing steadily for the past 10 years. An observational, nationwide cohort study was designed to examine the association between long-term exposure to fine particulate matter (PM) and the prevalence of immune-mediated diseases.
Clinical and demographic data were extracted from a nationwide dataset of men and women. Data on daily concentrations of PM10 and PM2.5 in the air were obtained from 2016 to 2020.
Of 81,363 subjects (mean age, 65 years) enrolled in the study, 91.9% were women. Among the 22% of subjects who had at least one comorbidity, 11.9% were diagnosed with an autoimmune disease.
The researchers found a small but positive association between exposure to PM10 and the risk of being diagnosed with an autoimmune disease. Every 10 micrograms per cubic meter ([mu]g/m3) increase in PM10 concentration was associated with a 7% higher risk of having any autoimmune disease. Subjects chronically exposed-a threshold of PM10 levels greater than 30 [mu]g/m3 or PM2.5 levels greater than 20 [mu]g/m3-had a 13% higher risk of developing an autoimmune disease. Exposure to high levels of PM10 was associated with an increased risk of rheumatoid arthritis but no other autoimmune diseases. Exposure to high levels of PM2.5 was associated with an increased risk of rheumatoid arthritis, connective tissue diseases, and inflammatory bowel diseases but no other autoimmune diseases.
The authors point out that the sample may not reflect the real prevalence of autoimmune disease in the general population. In addition, data on socioeconomic factors and smoking were lacking, as was information about other types of pollutants.