Association between polycyclic aromatic hydrocarbons exposure and bone turnover in adults

Background Cigarette smoking is a risk factor of osteoporosis and bone fracture. Tobacco smoke contains several polycyclic aromatic hydrocarbons. Thus, we hypothesized that environmental polycyclic aromatic hydrocarbon exposure is associated with bone loss and fracture risk. The present study examined the association between polycyclic aromatic hydrocarbon exposure and bone turnover in the general adult population. Methods A total of 1408 eligible participants from the National Health and Nutrition Examination Survey (NHANES 2001–2006) were included in this cross-sectional analysis. The levels of urinary N-telopeptide and serum bone-specific alkaline phosphatase, which are biomarkers of bone resorption and formation, respectively, were assessed. Meanwhile, polycyclic aromatic hydrocarbon exposure was evaluated using the concentrations of urinary polycyclic aromatic hydrocarbon metabolites. The association between polycyclic aromatic hydrocarbon exposures and N-telopeptide, and bone-specific alkaline phosphatase levels was assessed using a multivariate linear regression model. Results All polycyclic aromatic hydrocarbon metabolites except 3-phenanthrene were significantly associated with increased N-telopeptide levels ( P  < 0.05) after adjustment of relevant covariables. However, no significant relationship was observed between polycyclic aromatic hydrocarbon metabolites and bone-specific alkaline phosphatase levels. This relationship remained significant after the participants were assessed according to sex ( P  < 0.05). Additionally, all polycyclic aromatic hydrocarbon metabolites showed a positive association with N-telopeptide levels in participants aged <60 years ( P  < 0.05). Conclusion Polycyclic aromatic hydrocarbon exposure is associated with increased bone resorption among the general adult population in the United States. Further studies must assess the potential mechanisms associated with the adverse effects of polycyclic aromatic hydrocarbon exposure on bone loss.