Association between polycyclic aromatic hydrocarbons exposure and metabolic dysfunction-associated steatotic liver disease in US adults

Objective: To investigate the individual or combined effects of polycyclic aromatic hydrocarbons (PAHs) on metabolic dysfunction-associated steatotic liver disease (MASLD) in U.S. adults. Methods: We enrolled 3,130 participants aged 20 and over from the 2007-2016 National Health and Nutrition Examination Survey (NHANES) and analyzed six urinary PAH metabolites. The Poisson regression, Bayesian kernel machine regression (BKMR), and weighted quantile sum (WQS) regression models were used to assess the associations between PAHs and MASLD. Results: After adjusting for covariates, Poisson regression model showed significant associations [RRs (95% CIs)] between higher exposure quartiles of 2-hydroxynaphthalene (2-NAP) [Q2: 1.35 (1.06, 1.73); Q3: 1.67 (1.35, 2.07); Q4: 1.62 (1.23, 2.15); p-trend < 0.001], 2-hydroxyfluorene (2-FLU) [Q3: 1.36 (1.08, 1.70); p-trend = 0.073], 1-hydroxyphenanthrene (1-PHE) [Q4: 1.35 (1.03, 1.76); p-trend = 0.009], and 1-hydroxypyrene (1-PYR) [Q3: 1.37 (1.12, 1.69); Q4: 1.33 (1.01, 1.76); p-trend = 0.025] and MASLD (p < 0.05), compared with Q1. BKMR model exhibited a positive trend between mixed PAHs and MASLD. The WQS index constructed for six PAHs was significantly related to MASLD [OR (95% CI): 1.25 (1.06, 1.49)]. Conclusion: This study suggests that exposure to PAHs, individually or in combination, may be associated with an increased risk of MASLD.