Background: Polycyclic aromatic hydrocarbons (PAHs) are a group of ubiquitous environmental pollutants. In vivo and in vitro studies have demonstrated that PAHs can alter endocrine function, yet evidence from human studies is limited.
Objectives: The objective of this study was to investigate whether environmental exposure to PAHs was associated with altered reproductive hormone levels, using repeated measures of urinary OH-PAHs as biomarkers.
Methods: We measured 10 monohydroxylated PAHs (OH-PAHs) in repeated urine samples from 371 men in an infertility clinic in Wuhan, China. Multivariable linear regression models were used to estimate the associations between average urinary OH-PAH levels and serum reproductive hormones, and restricted cubic spline models were further used to examine the shapes of dose-response relationships.
Results: We observed dose-response associations of urinary 2-hydroxynaphthalene (2-OHNa) with decreased serum free testosterone (fT) and urinary 1-hydroxypyrene (1-OHP), 9-hydroxyphenanthrene (9-OHPh), and 9-hydroxyfluorene (9-OHFlu) with decreased serum estradiol (all P for trends <0.05). These associations were linear and significant when these four OH-PAHs were modeled as continuous variables in restricted cubic spline models. Furthermore, a U-shaped association was observed across urinary 4-OHPh levels, with lower levels of serum sex hormone-binding globulin (SHBG) at median concentrations compared with 5th and 95th percentile concentrations.
Conclusion: Environmental levels of PAH exposure in our study are associated with altered reproductive hormones. However, further research is needed to confirm our findings.
Keywords: Exposure; Male; Polycyclic aromatic hydrocarbons; Repeated measures; Reproductive hormone.
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