Synergistic interaction between polycyclic aromatic hydrocarbons and environmental tobacco smoke on the risk of obesity in children and adolescents: The U.S. National Health and Nutrition Examination Survey 2003-2008.

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) may be obesogens. However, the role of PAHs independent of environmental tobacco smoke (ETS) is unclear, and the interaction between PAHs and ETS remains unknown.

METHODS

We performed cross-sectional analyses of urinary concentrations of PAH metabolites, body mass index (BMI), and waist circumference (WC) in 1985 people aged 6-18 years using data from the 2003-2008 U.S. National Health and Nutrition Examination Survey. ETS exposure level was measured as serum cotinine level.

RESULTS

PAH metabolites were positively associated with BMI and WC in both the ETS-unexposed and ETS-exposed groups. The adjusted odds ratios for general obesity defined by age- and sex-specific BMI≥95th percentile across the quartiles of total PAH metabolites were 1, 4.51, 2.57, and 8.09 (Ptrend=0.003) in the ETS-unexposed group and 1, 2.02, 1.83, and 3.86 (Ptrend<0.001) in the ETS-exposed group. However, the association of PAH metabolites with obesity became stronger as serum cotinine levels increased (Pinteraction<0.05). Among those with high ETS exposure, the adjusted odds ratios for general obesity across quartiles of total PAH metabolites were 1, 2.89, 5.26, and 16.29 (Ptrend<0.001). Compared to the low PAH-exposure group without exposure to ETS, the high ETS- and high PAH-exposure group had 33.85- and 17.64-fold greater risks of general and central obesity, respectively.

CONCLUSIONS

Environmental exposure to PAHs may be associated with childhood obesity irrespective of ETS. In particular, simultaneous exposure to PAHs and ETS may substantially increase the risk of obesity.