The effects of PCB exposure and fish consumption on endogenous hormones.

Abstract

Previous studies have suggested that exposure to polychlorinated biphenyls (PCBs) may alter thyroid function, but data on effects of PCB exposure on other endogenous hormones has been lacking. The current study is ancillary to a larger investigation of the effects of Great Lakes fish consumption on PCBs and reproductive function. In the current study we examine associations of PCBs, 1,1-bis (4-chlorophenyl)-2,2-dichloroethene (DDE), and fish consumption with thyroid and steroid hormones in 178 men and PCBs, DDE, and fish consumption with thyroid hormones in 51 women from the original study. Serum PCB level and consumption of Great Lakes fish are associated with significantly lower levels of thyroxine (T(4)) and free thyroxine index (FTI) in women and with significantly lower levels of T(4) in men. Fish consumption, but not PCB level, is significantly and inversely associated with triiodothyronine (T(3)) in men. Results for thyroid-stimulating hormone (TSH) are inconsistent. Among men, there are significant inverse associations of both PCB and fish consumption with sex hormone-binding globulin (SHBG)-bound testosterone, but no association with SHBG or free testosterone. There are no significant overall associations of PCB, DDE, or fish consumption with estrone sulfate, follicle-stimulating hormone, luteinizing hormone, or dehydroepiandrosterone sulfate. The results of this study are consistent with previous studies showing effects of fish consumption and PCB exposure on thyroid hormones and suggest that PCBs may also decrease steroid binding to SHBG. Elucidation of specific mechanisms must await future investigations.

Serum PCBs, p,p′-DDE and HCB predict thyroid hormone levels in men

“…Inconsistent with our findings were results from two other human studies that found no associations between p,p′-DDE and thyroid hormones in adult men (Hagmar et al 2001a;Persky et al 2001). Also inconsistent with our results but consistent with what they reported for HCB and PCBs, Takser et al (2005) found an inverse association between p,p′-DDE and total T 3 with no associations between p,p′-DDE and free T 4 or TSH in pregnant women.…”

“…Likewise, inverse associations between PCBs and T 3 levels were also previously observed in the wives of Swedish fishermen (Hagmar et al 2001b) and in German schoolchildren (Osius et al 1999), while another study among Dutch women reported an inverse association with T 3 that was also accompanied by an inverse association with T 4 and a positive association with TSH (Sala et al 2001). Other studies have reported an inverse association between PCBs, and T 4 and/or a positive association between PCBs and TSH, with no association between PCBs and total T 3 (Schell et al 2004;Hagmar 2003;Persky et al 2001;Emmett et al 1988), while another reported no associations between PCBs and thyroid hormones among 160 neonates from North Carolina from 1978 to 1982 (Longnecker et al 2000).…”

“…The associations for PCBs remained after adjusting for confounding by weight loss, as weight loss is independently associated with decreased T 3 and with increased concentrations of lipophilic compounds, such as organochlorines, that are released from adipose tissue during fat mobilization which leads to increased concentrations in circulating blood. Conversely, a study of 110 Swedish fishermen reported no associations between PCBs, HCB, DDT or p,p′-DDE and thyroid hormones (Hagmar et al 2001a), while a study of 178 U.S. men that had fished in the Great Lakes reported an inverse association between PCBs and total T 4 but no association with total T 3 (Persky et al 2001).…”

“…In addition, several human studies have investigated associations between levels of these compounds in the body and thyroid hormone levels (Takser et al 2005;Schell et al 2004;Bloom et al 2003;Hagmar 2003;Pelletier et al 2002;Hagmar et al 2001a;2001b;Persky et al 2001;Sala et al 2000;Longnecker et al 2000;Osius et al 1999;Koopman-Esseboom et al 1994;Emmett et al 1988). However, study populations have differed greatly and results have not been consistent across studies.…”

A longitudinal examination of factors related to changes in serum polychlorinated biphenyl levels.

“…Polychlorinated biphenyls (PCBs) have been linked to a broad range of adverse health effects in humans, from developing fetuses to aging adults (Fein et al 1984;Hicks 1996;Lai et al 2001;Persky et al 2001;Rylander et al 1998;Sauer et al 1994;Schantz et al 1996;Yu et al 1991). However, efforts to ascertain historical PCB exposure and determine a causal relationship with health outcomes such as cancer and immune dysfunction have yielded inconsistent results (Hansen 1998;Kimbrough 1995;Wolff and Toniolo 1995).…”