Associations between exposure to polycyclic aromatic hydrocarbons and metabolic syndrome in U.S. adolescents: Cross-sectional results from the National Health and Nutrition Examination Survey (2003-2016) data

Abstract

Background: The metabolic syndrome is a constellation of risk factors, including abdominal obesity, hypertension, dyslipidemia, and hyperglycemia. Polycyclic aromatic hydrocarbons (PAHs) constitute a group of chemicals that are formed during the incomplete combustion of coal, oil and gas, garbage, and other organic substances. In the occupational exposure population, PAHs exposure increased the prevalence ratio of metabolic syndrome. However, the effect of PAHs on prevalence of metabolic syndrome in adolescents has not been reported. Because of the propensity for childhood metabolic risk to track into adulthood, there is a great need to identify risk factors for childhood metabolic syndrome.

Method: Using data from the 2003-2016 National Health and Nutrition Examination Survey. We defined metabolic syndrome using a modified version of the National Cholesterol Education Program Adult Treatment Panel Ⅲ definition for adolescents. Weighted logistic regression was used to calculate the odds ratio and 95 % confidence intervals for each biomarker. In addition, we applied the weighted quantile sum (WQS) regressions to adolescent metabolic syndrome to reveal the multiple exposure effects and relative weights of each PAH.

Results: Among the 827 adolescents, 183 (22.13 %) had metabolic syndrome. The levels of 2-hydroxynaphthalene (2-NAP), 2-hydroxyphenanthrene (2-PHE), 2-hydroxyfluorene (2-FLU), 1-hydroxynaphthalene (1-NAP), 3-hydroxyfluorene (3-FLU) and 1-hydroxypyrene (1-PYR) were higher in the group of adolescents with metabolic syndrome. There were positive associations between higher concentrations of 2-NAP, 2-FLU and odds of metabolic syndrome after adjustment, which odds ratios (ORs) in the 3rd tertile were 2.22 (95%CI:1.45-3.44) and 2.09 (95%CI:1.36-3.10), respectively. In subgroups analysis, the ORs between the 3 tertile concentrations of 2-NAP, 2-PHE and high fasting blood glucose (FBG) were 2.20 (95%CI:1.37-3.57) and 1.99 (95%CI:1.16-3.48).

Conclusion: The present study suggested that PAHs may be associated with odds of metabolic syndrome as well as individual metabolic syndrome components among adolescents. A cohort study should be designed to clarify the cause and effect between PAHs and metabolic syndrome in future research.

Keywords: Environmental exposure; Metabolic syndrome; NHANEs; Polycyclic aromatic hydrocarbons.