Association between mixed exposure of polycyclic aromatic hydrocarbons and telomere length in general population: NHANES 2001–2002

Although an association between single polycyclic aromatic hydrocarbons (PAHs) adult exposure and telomere length has been reported, the evidence of mixed PAHs (1-napthol, 2-napthol, 3-fluorene, 2-fluorene, 3-phenanthrene, 1-phenanthrene, 2-phenanthrene, and 1-pyrene) exposure and telomere length in the adult general population is still not clear. A total of 1460 adults over the age of 20 years provided urine information on 8 PAHs and selected covariates from the 2001–2002 National Health and Nutrition Examination Survey (NHANES). Bayesian nuclear machine regression (BKMR) was conducted to analyze these associations of telomere length in multiple PAH-exposed environments. Linear regression is mainly used for correlation analysis of PAHs with selected covariate adjustments. Restricted cubic spline (RCS) is used to estimate the correlation between selected PAHs and telomere length. After adjusting for potential covariates, PAHs mixed exposure was negatively associated with telomere length. The linear regression results showed that 2-napthol and 2-fluorene were negatively correlated with telomere length. Telomere length decreased by 1.0% in the fully adjusted model per increment of one unit in the base-10-logarithm-transformed 2-napthol and 2-fluorene concentrations (P = 0.030 and 0.049, respectively). However, the other 6 PAH metabolites were not significantly different. In addition, RCS results showed that 2-napthol has a marginal dose effect relationship with telomere length. Our present study suggested that PAHs are negatively associated with telomere length in the general population of the USA. Considering that the low level of PAHs exposure in the general population can also induce reduced telomere length and potential health risks, future research is needed to explore potential mechanisms.