Chronic air pollutant exposure increase the risk of systemic lupus erythematosus, finds study

A new study published in the journal of Arthritis & Rheumatology found that exposure to high levels of common air pollutants considerably elevated the risk of developing new-onset systemic lupus erythematosus (SLE), which was true in persons with known genetic risk factors.

Meiqi Xing and colleagues undertook this study to investigate the connection between long-term exposure to air pollutants and incident SLE, as well as assessing interactions and joint effects of genetic risk and air pollutants.

This study included a total of 4,59,815 people from the UK Biobank. By utilizing a land-use regression model, the concentrations of nitrogen dioxide [NO2], nitrogen oxides [NOx], fine particulate matter with diameter ≤2.5 μm [PM2.5], and particulate matter with diameter ≤10 μm [PM10] were calculated. This study employed Cox proportional hazards model to investigate the connections between air pollution and SLE incidents and polygenic risk score (PRS) to further evaluate the interactions and combined impacts of genetic risk and air pollution.

The key findings of this study were:

A total of 399 SLE patients in all were found over a period of 11.77 years median follow-up. The adjusted hazard ratios for each interquartile range increase in PM2.5, PM10, NO2, and NOx were 1.18 , and 1.13 (1.03–1.23) that indicated positive associations between air pollutant exposure and incident SLE.

This study found that individuals with a higher genetic risk and higher exposure to air pollution were more likely to experience an incident case of SLE when compared to the individuals with a lower genetic risk and a lower exposure to air pollution.

Also, a noteworthy multiplicative interaction was seen between PRS and NO2. Apart from the small number of incident SLE cases and the sample who were primarily middle-aged, other limitations of the study included the voluntary enrollment of participants in the Biobank (indicating that they might be more health-conscious than others) and the possibility that individual exposure to pollutants may vary more than what the annual estimates captured. Also, a number of potential confounders were not taken into consideration, including exposure to silica dust or other pollutants like ground-level ozone.

Overall, this investigation revealed a important concern about environmental variables causing autoimmune illness. These results can help design more stringent air quality standards that could reduce the exposure to dangerous pollutants and lower the chance of developing sickle cell disease.

Reference:

Xing, M., Ma, Y., Cui, F., Li, D., Wang, J., Tang, L., Zheng, L., Yang, J., & Tian, Y. (2024). Air Pollution, Genetic Susceptibility, and Risk of Incident Systemic Lupus Erythematosus: A Prospective Cohort Study. In Arthritis & Rheumatology. Wiley. https://doi.org/10.1002/art.42929