Epidemiological studies have established a connection between environmental factors and the prevalence of non-alcoholic fatty liver disease (NAFLD).Fine particulate matter with an aerodynamic diameter 2.5 m (PM2.5), a major component of ambient air pollution, has been implicated in systemic inflammation and metabolic dysfunction.The waist-hip ratio (WHR), an important measure of body composition, is a key risk factor for metabolic syndrome and NAFLD.We investigated the association between ambient PM2.5 exposure, WHR, and NAFLD.We used data from the Taiwan Biobank collected between 2016 and 2020, involving 15,049 individuals aged 30 to 70 years.Ambient PM2.5 exposure was estimated using a land-use regression model and categorized into quartiles.NAFLD was identified using liver function tests and imaging, and WHR was classified as normal or abnormal based on sex-specific cutoffs.Participants with NAFLD (n = 7179) had higher body mass index, a greater prevalence of abnormal WHR, and less favorable lipid profiles compared with those without NAFLD (n = 7870).Higher PM2.5 exposure was associated with increased odds of NAFLD, with participants in the highest quartile (PM2.5 > 39.85 g/m) showing an odds ratio (OR) of 1.251 (95% CI: 1.114-1.404).An abnormal WHR was also associated with higher odds of NAFLD (OR = 1.641, 95% CI: 1.507-1.787).A statistically significant interaction between PM2.5 exposure and WHR was observed, with individuals with abnormal WHR exhibiting consistently higher odds of NAFLD across all PM2.5 quartiles.In the highest PM2.5 quartile, participants with abnormal WHR had an OR of 2.020 (95% CI: 1.708-2.389),compared with an OR of 1.442 (95% CI: 1.215-1.712)among those with normal WHR.These findings suggest that central obesity may amplify the association between PM2.5 exposure and NAFLD, highlighting the importance of integrated public health strategies targeting both air pollution and metabolic health.
Chang et al. (Mon,) studied this question.