Abstract
BACKGROUND: Evidence regarding the association between ambient polycyclic aromatic hydrocarbon (PAH) mixtures and non-neoplastic gastrointestinal diseases in general populations remains limited. This study examined whether provincial ambient particulate-phase PAH burden was associated with prevalent gastrointestinal disease among middle-aged and older adults in China. METHODS: Provincial annual mean concentrations of particulate-phase PAHs for 2015 were compiled from published monitoring studies across 12 Chinese provinces and linked to participants in the 2015 wave of the China Health and Retirement Longitudinal Study. Gastrointestinal disease was defined as a self-reported physician diagnosis and/or current treatment, excluding tumors and cancer. Using multivariable logistic regression, we estimated odds ratios and 95% confidence intervals for prevalent gastrointestinal disease per doubling (log2) of total PAHs and of 17 individual PAHs, adjusting for demographic, socioeconomic, and health-related covariates. The Benjamini-Hochberg procedure controlled the false discovery rate. Likelihood ratio tests for interaction were used to assess effect modification. RESULTS: Of 3,671 adults aged 45 years or older, 1,056 (28.8%) reported a gastrointestinal disease. In fully adjusted models, each doubling of total PAH concentration was associated with increased odds of gastrointestinal disease (odds ratio 1.07, 95% confidence interval 1.02-1.12; false discovery rate-adjusted q = 0.014). Following multiple-comparison correction, naphthalene, fluorene, phenanthrene, and pyrene each demonstrated consistent positive associations. The association for total PAHs was more pronounced among non-drinkers (odds ratio 1.43, 95% confidence interval 1.19-1.71; P for interaction = 0.015) and rural residents (odds ratio 1.37, 95% confidence interval 1.15-1.65; P for interaction = 0.035). CONCLUSIONS: Higher provincial ambient particulate-phase PAH burden was associated with a greater prevalence of self-reported non-neoplastic gastrointestinal disease among middle-aged and older Chinese adults, with potential heterogeneity by residence and alcohol consumption. Given the cross-sectional design and province-level exposure assignment, longitudinal studies with individual-level exposure assessment and validated outcomes are needed.