The nonlinear impact of air pollutants and solar radiation exposure on the risk of hospitalisation for pterygium among adults in Shanghai, China: a time series analysis.

Background: In recent years, many studies have focused on the effects of air pollution on ocular surface health. However, there is currently little research on the relationship between pterygium and air pollution. We aimed to investigate the effects of air pollutants and solar radiation on the progression of pterygium in adults through a 5-year time series analysis.

Methods: After collecting the meteorological data and clinical visits for pterygium in Shanghai, China from 2017 to 2023, we established a distributed lag nonlinear model (DLNM) for statistical analysis. We also conducted subgroup analysis according to age and sex to investigate the impact of risk factors on different populations.

Results: This cohort included a total of 57 211 cases. We found that solar radiation, particulate matter less than 2.5 micrometre (μm) (PM_2.5), ozone (O₃) and nitrogen dioxide (NO₂) all increased the risk of outpatient treatment of pterygium within a certain concentration range. Among them, PM_2.5 and solar radiation have the most significant lag effects. The relative risk (RR) value was highest when the concentration of PM_2.5 reach the peak value at a lag time of 13 days. Subgroup analysis showed that women and people aged 55 to 65 years were more susceptible to extremely high concentrations of PM_2.5.

Conclusions: Our results suggested that in addition to solar radiation, which is recognized as a risk factor for pterygium, PM_2.5 exposure also seems to be related with an increase in the risk of pterygium. More targeted prevention and early interventions strategies remain to be studied.