Abstract
BACKGROUND: The general population is exposed to the group of endocrine disrupting chemicals persistent organic pollutants (POPs), that includes polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). OBJECTIVES: The aim of this research was to evaluate the associations of serum levels of PCB, PCDD, and PCDF congeners with follicle stimulating hormone (FSH) and luteinizing hormone (LH) in postmenopausal women not taking exogenous hormones. We hypothesized that associations of POPs with these gonadotropins could be modified by factors affecting endogenous hormones. METHODS: Cross-sectional analyses were conducted on data from 89 postmenopausal women using data from the National Health and Nutrition Examination Survey (NHANES). POPs were summarized based on classification schemes thought to reflect toxicological properties. Associations of POPs and gonadotropin hormones were modeled with multivariable regression models. When evidence of interaction was found, conditional effects were estimated. RESULTS: We found inverse associations of LH, but not FSH, with exposure to anti-estrogenic and/or dioxin-like POPs, but not with non dioxin-like PCBs. A doubling of dioxin-like toxic equivalents (TEQs) was associated with a decrease in LH of 11.9% (95% CI = -21.3%, -1.4%, p = 0.03). Inverse associations were enhanced by potential effect modifiers related to both direct and indirect estrogenicity, including obesity and the obesity-related condition inflammation. CONCLUSIONS: These investigations support a pattern of endocrine-disrupting effects by dioxin-like POPs among postmenopausal women, especially those with conditions related to peripheral estrogenicity.