Obesity as a Mediator in the Association Between Urinary Polycyclic Aromatic Hydrocarbon Exposure and Liver Fibrosis Risk in US Adults

Abstract

Polycyclic aromatic hydrocarbons (PAHs) exposure may be associated with obesity-mediated liver injury. However, there is lacking evidence on the role of obesity in associations of PAHs exposure with liver fibrosis among population-based study. Participants were sourced from the National Health and Nutrition Survey 2001-2016. Urinary metabolites of PAHs were analyzed using gas chromatography-mass spectrometry. Liver fibrosis was classified as low and high risk. The weight-adjusted waist index (WWI) was calculated by waist circumference divided by the square of Weight. Logistic regression models and WQS regression were used to explore associations between exposure to six types of PAHs and the risk of liver fibrosis in adults and further analyzed the mediating effects of obesity on the above-mentioned associations. Multiple-urinary PAHs metabolites were associated with increased the risk of liver fibrosis. Positive association between mixture of 6 PAHs and liver fibrosis (OR: 1.41, 95% CI: 1.10-1.80) were found and 2-naphthol, 1-pyrene, 1-naphthol, and 2-fluorene were the primary contributor to this association. Furthermore, the proportion mediation of obesity on associations of individual and the mixture of PAHs with liver fibrosis ranged from 4.6% to 38.3%. This study results showed that exposure to the mixture of PAHs was associated with increased liver fibrosis and these associations were partially mediated by obesity.