Associations between particulate matter air pollutants and hospitalization risk for systemic lupus erythematosus: a time-series study from Xi’an, China

Air pollution exposure is an important environmental risk factor involved in the development of systemic lupus erythematosus (SLE). This study was conducted to investigate the relationships between particulate matter (PM) air pollutants exposure and the risk of SLE admission in Xi'an, China. The records of SLE admission, air pollutants and meteorological data were retrieved from the First Affiliated Hospital of Xi'an Jiaotong University, the Xi'an Environmental Monitoring Station and China Meteorological Data Network, respectively. A distributed lagged nonlinear model combined with Poisson generalized linear regression was used to evaluate the effect of air pollution on SLE admission. Exposure-response curves showed positive associations of PM ≤ 2.5 (PM