Ambient air pollution and hospitalization of wide-spectrum digestive diseases: A nationwide case-crossover study in China.

Previous evidence on the short-term associations between air pollutants and digestive diseases is limited. We conducted a time-stratified case-crossover study among patients with digestive diseases across 153 hospitals in 20 provincial-level regions in China during 2013-2021. Daily concentrations of air pollutants were obtained from the nearest fixed-site monitoring stations. Conditional logistic regression models were applied. Subset analyses were performed to identify potential effect modifiers. A total of 783,090 hospital admission records of digestive diseases were included in the analysis. Significant associations of fine particulate matter (PM2.5), sulfur dioxide (SO2), nitrogen dioxide (NO2), and carbon monoxide (CO) with hospitalizations for total digestive diseases were observed. Each 10 μg/m3 increase in PM2.5, SO2, NO2, and 1 mg/m3 increase in CO concentrations during lag 01 day was associated with 0.19 % (95 % confidence interval: 0.08 %, 0.31 %), 0.45 % (0.13 %, 0.77 %), 0.81 % (0.59 %, 1.03 %), and 2.10 % (1.22 %, 2.98 %) increase in the risk of digestive hospitalization, respectively. The exposure-response curves were positive and almost linear for PM2.5 and NO2. In contrast, non-significant associations were found for coarse particulate matter and ozone. Diseases of the esophagus, stomach, and duodenum as well as diseases of noninfective enteritis and colitis were significantly associated with most air pollutants. There were stronger effects among females, patients aged under 65 years, and during cold season. This nationwide study provides evidence on the significant associations between short-term air pollutants exposure and hospitalization of total digestive diseases. Our results shed light on the broader health impacts of air pollution, particularly emphasizing the threats to the digestive system.