The effect of short-term air pollutants exposure on outpatient admission for blepharitis in Shanghai, China: a hospital-based study

Blepharitis is a very common ophthalmologic disease, and few studies have examined if air pollutants contribute to the risk of blepharitis. We investigated the presence of any potential correlation between exposure to air pollution and outpatient admission for blepharitis in Shanghai, China. Data on daily outpatient admission for blepharitis were collected from January 2017 to July 2022. Air pollution and meteorological data were acquired from the Shanghai Environmental Protection Agency. Using the distributed lag non-linear model (DLNM) we investigated the relationship between air pollutants and blepharitis. Seasonal stratified analysis was carried out. In total, 10,681 blepharitis patients were recruited. In the single-pollutant model, a 10 μg/m 3 increase in particulate matter with < 2.5 μm PM 2.5 and 10 μm PM 10 along with sulfur dioxide (SO 2 ) and 100 μg/m 3 increase in carbon monoxide (CO) was significantly associated with outpatient visits for blepharitis. In the multi-pollutant model, a 10 μg/m 3 increase in ozone (O 3 ) and nitrogen dioxide (NO 2 ) and a 100 μg/m 3 increase in carbon monoxide (CO) was significantly associated with outpatient visits for blepharitis. Moreover, there was an obvious relationship between blepharitis and PM 2.5 and O 3 in the summers and blepharitis and PM 10 , NO 2 , and SO 2 during the winters. Exposure to short-term air pollution increases the risk of blepharitis outpatient visits in Shanghai, China.