Serum concentrations of p, p′-DDE, HCB, PCBs and reproductive hormones among men of reproductive age
Highlights
► We examined relationships between PCB exposure and sex hormones in adult males with fertility problems. ► Exposure was at levels consistent with those observed in the general US population. ► In crude models, PCBs were negatively associated with several sex hormones. ► In full models results were attenuated but some significant relationships remained. ► PCB exposure may be associated with circulating sex hormone levels in adult males.
Section snippets
Background
Polychlorinated biphenyls (PCBs) were used extensively in the US until 1977 as insulators and lubricants in manufacturing [1]. Despite their discontinued use, they remain persistent in the environment because they are slow to break down in soil and bioaccumulate in fatty animal products in the food chain. Hexachlorobenzene (HCB) and dichlorodiphenyltrichloroethane (DDT), also no longer in use in the US by 1980, similarly continue to pose an exposure risk to humans [2], [3]. Data from the
Study population
Subjects were male partners, aged 18–51, in subfertile couples seeking infertility evaluation and treatment at Massachusetts General Hospital (MGH) between January 2000 and May 2003 [21]. Males who were undergoing postvasectomy semen analysis or who were being treated for infertility with exogenous hormones were ineligible for participation [22]. Sixty-five percent of males (N = 358) approached agreed to participate, and those who did not primarily reported lack of time on day of visit as their
Population characteristics
Of the 358 subjects enrolled in the study, 2 did not have hormone data and 15 were currently using hormonal medications and were excluded from analysis, leaving a final sample size of 341. Most participants were white (84%) and had never smoked (72%), and the average age and BMI were 36 and 28, respectively. Many participants (44%) showed no abnormalities in sperm concentration, motility or morphology, and a small proportion showed abnormalities in all three (11%). Relationships between semen
Discussion
Though several studies examined association between exposure to PCBs, p, p′-DDE and HCB and reproductive hormones in humans, none have thoroughly investigated relationships with such a large panel of exposures in populations of adult males of reproductive age exposed to levels on the order of those observed in the general US population. Studies of PCB associations with reproductive hormones have been primarily in groups highly exposed through fish consumption, and have varied greatly both by
Conclusions
Despite these limitations our study provides notable results. It is the first study to investigate the relationship between a wide range of POP exposures, at levels comparable to those in the general US population, with sex hormones in men of reproductive age. We observed many significant relationships in crude models without lipid adjustment, however in full models with the inclusion of serum lipids, age and BMI as covariates nearly no associations between POPs and reproductive hormone levels
Acknowledgments
This work was supported by grants P30ES000002, R01ES009718, R01ES018872, P20ES018171, P42ES017198, and P30ES017885 from the National Institute of Environmental Health Sciences (NIEHS), and RD83480001 from the US Environmental Protection Agency (USEPA).
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