Heatwave exposure and gastrointestinal and liver diseases: complementary evidence from a population-based study and animal experiments.

BACKGROUND

Heatwaves are becoming increasingly frequent under climate change, yet their association with gastrointestinal (GI) and liver diseases remains poorly understood. This study aimed to evaluate the association between heatwave exposure and the prevalence of GI and liver diseases in middle-aged and older adults and to explore the biological plausibility using a heat-exposure mouse model.

METHODS

We analyzed 10,409 participants from the 2015 China Health and Retirement Longitudinal Study (CHARLS) using 12 city-level heatwave definitions and applied multivariable logistic regression models to evaluate associations between heatwave exposure and the prevalence of GI and liver diseases. A heat exposure mouse model was further used for histopathological, biochemical, immunofluorescence, inflammatory, and gut microbiome analyses.

RESULTS

Heatwave exposure was significantly associated with a higher prevalence of gastrointestinal and liver diseases in middle-aged and older adults, with a sex-divergent pattern observed in subgroup analyses. Smokers also showed stronger associations between heatwave exposure and disease prevalence. In mice, heat exposure induced gastrointestinal and hepatic injury, accompanied by dysregulated metabolism, elevated ALT, AST, TNF-α, and LPS levels, reduced colonic ZO-1 expression, and marked alterations in gut microbial composition and predicted metabolic pathways.

CONCLUSION

These findings suggest that heatwave exposure is associated with GI and liver diseases and may be related to gut microbiome dysregulation.