Environmental polycyclic aromatic hydrocarbon exposure in relation to metabolic syndrome in US adults

The present study examined the associations of polycyclic aromatic hydrocarbon (PAH) exposure with metabolic syndrome (MetS) and its components. Data were from 5181 US adults recruited in the National Health and Nutrition Examine Survey 2001-2012. Environmental PAH exposure was estimated as concentrations of urinary PAH metabolites. Weighted quantile sum (WQS) regression and modified Poisson regression were separately conducted to estimate the associations of mixed and single PAH metabolites with MetS and its components. WQS regression analyses showed that participants with higher mixed PAH exposure had increased prevalence of MetS (prevalence ratio, 1.12; 95 % confidence interval, 1.06, 1.19), elevated waist circumference (1.07; 1.02, 1.12), elevated fasting blood glucose (1.07; 1.00, 1.14), elevated triglycerides (1.19; 1.09, 1.30), and reduced high-density lipoprotein cholesterol (1.11; 1.03, 1.20). In the models for single PAH metabolites, higher levels of 1-hydroxynaphthalene (1.15; 1.00, 1.32), 2-hydroxynaphthalene (1.20; 1.05, 1.38), 1-hydroxyphenanthrene (1.18; 1.04, 1.34), 2-hydroxyphenanthrene (1.38; 1.22, 1.57), and 1-pyrene (1.19; 1.05, 1.34) were respectively associated with increased prevalence of MetS (highest tertile vs lowest tertile). In addition, linear trends were noted for the associations of these PAH metabolites with MetS (all P for linear association ≤0.047). Smokers, drinkers, and participants with poor diet quality showed stronger associations between certain PAH metabolite with MetS. The findings suggest that the prevalence of MetS and its components increases when PAH exposure is at a high level, and that lifestyle factors, such as cigarette smoking, alcohol consumption, and diet quality, could modify the positive associations of certain PAH exposure with MetS.