Observational studies: Ambient air pollution and hospitalization for RA-ILD in a heavily polluted city in China

Little is known within the medical community about the impact of air pollution on hospital admissions due to rheumatoid arthritis associated with interstitial lung disease (RA-ILD). Our research aimed to explore whether there is a correlation and to estimate how the association was distributed across various lags in Jinan, China. The relationships between ambient air pollutant concentrations, including PM(2.5), PM(10), sulfur dioxide (SO(2)), ozone (O(3)), and nitrogen dioxide (NO(2)), and monthly hospitalizations for RA-ILD were studied by employing a general linear model with a Poisson distribution. This time-series study was performed from January 1(st), 2015 to December 31(st), 2019. In the 5-year study, there were 221 hospitalizations for RA-ILD in Jinan city. The levels of PM(2.5), PM(10), SO(2), and NO(2) were significantly related to the number of admissions for RA-ILD. PM(2.5), PM(10), and SO(2) showed the most significant effect on the month (lag 0), and NO(2) was most related to RA-ILD at a lag of two months (lag 2). The monthly admissions of RA-ILD increased by 0.875% (95% CI: 0.375–1.377%), 0.548% (95% CI: 0.148–0.949%), 1.968% (95% CI: 0.869–3.080%), and 1.534% (95% CI: 0.305–2.778%) for each 10 μg/m(3) increase in PM(2.5), PM(10), SO(2) and NO(2), respectively. This study might add more detailed evidence that higher levels of PM(2.5), PM(10), SO(2) and NO(2) increase the risk of hospitalizations for RA-ILD. Further study of the role of air pollution in the pathogenesis of RA-ILD is warranted.