Abstract  Although the commercial synthesis of polychlorinated biphenyls (PCBs) has been banned in the United States for several decades, they are persistent in the environment with exposure mainly being through diet. The biologic and toxic effects of PCBs and their metabolites are due in part to their ability to interact with several cellular and nuclear receptors, thereby altering signaling pathways and gene transcription. These effects include endocrine modulation and disruption. Therefore, the natural history of cancer in tissues expressing these receptors may be modulated by PCB congeners, which are known to have estrogenic, antiestrogenic, and other hormonal effects. Several frameworks for grouping PCB congeners based on these interactions have been proposed. We conducted a hospital-based, case-control pilot study of 58 prostate cancer cases and 99 controls to evaluate the association between the proposed PCB groupings and the risk of prostate cancer. Serum samples were analyzed for a total of 30 PCBs. In multivariate analyses, the odds of prostate cancer among men with the highest concentrations of moderately chlorinated PCBs or PCBs with phenobarbital-like activities (constitutively active receptor (CAR) agonists) was over two times that among men with the lowest concentrations. Increasing trends in risk across the concentration levels were also observed. These results suggest that a higher burden of PCBs that are CAR agonists may be positively associated with an increased risk of prostate cancer and they encourage further research in this area.

Abstract  EIS: Epidemiology Information System

Abstract  The aim of the study was to assess whether a correlation may be found between dioxin-like compounds exposure and the presence of endometriosis. 22 Italian and 18 Belgian women underwent laparoscopy: 23 cases had endometriosis, 17 women had no evidence of the disease. PCDD+PCDF and/or dioxin-like PCB levels were measured in blood samples. No significant differences were found in "dioxin" levels between women with and without endometriosis, but the body burdens of the Italians resulted significantly lower than that of the Belgians. The latter result and the higher incidence of endometriosis in this Country, makes the hypothesis of a correlation between these chemicals an endometriosis worthwhile to be further explored.

Abstract  Environmental pollutants can act as endocrine modulators. In this study, we examined whether weight loss-induced changes in plasma organochlorine compounds (OC) were associated with those in plasma insulin levels. Fasting insulin and the area under the curve (AUC) of insulin after a 75-g oral glucose load, plasma levels of 1 commercial polychlorinated biphenyl (PCB) mixture (Aroclor 1260), 1 PCB congener (PCB 153), and 3 pesticides (2,2'-bis(4-chlorophenyl)-1,1-dichloroethylene (p,p'-DDE), beta-hexachlorocyclohexane (beta-HCH), and hexachlorobenzene (HCB)) were measured before and after a 15-week weight loss program induced by a caloric restriction in a sample of obese men and women. Both genders showed a similar reduction in body weight (approximately 11 kg) in response to treatment, although men lost significantly more fat mass than women (mean +/- SD 9.4 +/- 4.1 v 5.9 +/- 5 kg, respectively, P <.05). Fasting insulin and AUC of insulin significantly decreased in men and women after the treatment. In response to weight loss, a significant increase in OC was observed in both genders, and this effect was more pronounced in men. The greater the increase in plasma OC levels, the greater the reduction in fasting insulin was in response to weight loss in men (-.49 < r < -.59, P <.05), but not in women (-.22 < r <.01, not significant [NS]). In both genders, no relationship was observed between changes in plasma OC levels and changes in AUC of insulin (-.41 < r < -.08, NS). In men, relationships between changes in plasma HCB, Aroclor 1260, and PCB-153 concentrations and those in fasting insulin levels in response to weight loss remained significantly correlated after correction for fat mass loss (-.46 < partial r < -.51, P values ranging from.05 to.07). These results suggest that weight loss-induced increase in plasma pollutant levels tends to be independently associated with the reduction of fasting insulin levels in men, but not in women. Further studies are needed to verify whether these findings are causally related.

Abstract  BACKGROUND: Some chemicals appear to have hormonally active properties in animals, but data in humans are sparse. Therefore, we examined ovarian function in relation to organochlorine compound levels.

METHODS: During 1997-1999, 50 Southeast Asian immigrant women of reproductive age collected urine samples daily. These samples were assayed for metabolites of estrogen and progesterone, and the women's menstrual cycle parameters were assessed. Organochlorine compounds (including DDT, its metabolite DDE, and 10 polychlorinated biphenyl [PCB] congeners) were measured in serum.

RESULTS: All samples had detectable DDT and DDE, with mean levels higher than typical U.S. populations. Mean cycle length was approximately 4 days shorter at the highest quartile concentration of DDT or DDE compared with the lowest. After adjustment for lipid levels, age, parity, and tubal ligation, and exclusion of a particularly long cycle, the decrements were attenuated to less than 1 day, with wide confidence intervals (CIs). The adjusted mean luteal phase length was shorter by approximately 1.5 days at the highest quartile of DDT (95% CI = -2.6 to -0.30) or DDE (-2.6 to -0.20). With each doubling of the DDE level, cycle length decreased 1.1 day (-2.4 to 0.23) and luteal phase length decreased 0.6 days (-1.1 to -0.2). Progesterone metabolite levels during the luteal phase were consistently decreased with higher DDE concentration. PCB levels were not generally associated with cycle length or hormone parameters after adjustment, and they did not alter the DDE associations when included in the same models.

CONCLUSIONS: This study indicates a potential effect of DDE on ovarian function, which may influence other end points such as fertility, pregnancy, and reproductive cancers.

Abstract  BACKGROUND: Endometriosis, a gynecologic disorder affecting 8-10% of reproductive-age women in the United States, is defined as the presence of endometrial tissue outside the uterus and is linked to pelvic pain and infertility. Environmental contaminants, including polychlorinated biphenyls (PCBs), are hypothesized to contribute to endometriosis risk through effects on steroid hormones.

OBJECTIVE: We evaluated serum concentrations of certain noncoplanar PCBs, which have no or only weak dioxin-like properties, as risk factors for endometriosis.

METHODS: In a case-control study of Group Health enrollees in western Washington State, 20 PCB congeners were measured in serum from surgically confirmed endometriosis cases that were newly diagnosed between 1996 and 2001 (n = 251) and from female controls matched for age and reference year (n = 538).

RESULTS: Summed and estrogenic PCB concentrations were not associated with endometriosis risk [summed: odds ratio (OR) = 1.3; 95% confidence interval (CI), 0.8-2.2; estrogenic: OR = 1.1; 95% CI, 0.8-1.4]. Although several congener-specific ORs were statistically above or below the null (PCB 170: third quartile vs. lowest: OR = 0.5; 95% CI, 0.3-0.9; PCB 196: third quartile vs. lowest: OR = 0.4; 95% CI, 0.2-0.7; PCB 201: second vs. lowest: OR = 0.5; 95% CI, 0.3-0.8; third quartile vs. lowest: OR = 0.4; 95% CI, 0.2-0.7), there were no overall consistent patterns of endometriosis risk.

CONCLUSIONS: Taken in context with other North American studies, our findings suggest that noncoplanar PCB concentrations consistent within the range of exposure currently observed in western Washington State do not contribute meaningfully to endometriosis risk.

Abstract  OBJECTIVE: To investigate the possible association between birth size and cord concentrations of some organochlorine compounds (OCs), including 4,4'-dichlorodiphenyltrichloroethane (DDT), 4,4'-1,1-dichloro-2,2-bis(p-dichlorodiphenyl)ethylene (DDE), hexachlorobenzene (HCB), β-hexachlorocyclohexane (β-HCH), 4 polychlorinated biphenyl (PCB) congeners (118, 138, 153, and 180), and their sum (ΣPCBs) in a birth cohort in Valencia, Spain.

STUDY DESIGN: A total of 494 mothers and their newborns (born 2003-2006) participated in the study. Multivariate linear regression analyses were performed between birth weight, length, or head circumference and OC concentrations.

RESULTS: Median concentrations of 4,4'-DDT, 4,4'-DDE, HCB, β-HCH, and ΣPCBs were 0.02, 0.46, 0.22, 0.09, and 0.35 ng/mL, respectively. For birth weight there was a significant decrease of 63 and 107 g for each 10-fold increase in cord serum 4,4'-DDT and 4,4'-DDE concentrations, and a marginally significant decrease of 79 and 53 g for each 10-fold increase in HCB and β-HCH concentrations. A significant decrease of 0.39 cm in birth length was found for each 10-fold increase in HCB concentrations. For newborns with cord 4,4'-DDT concentrations above the median there was a significant decrease of 0.26 cm in birth head circumference.

CONCLUSIONS: These results reveal that prenatal exposure to some OCs could impair the anthropometric development of the fetus, reducing the birth weight, length, and head circumference.

Abstract  BACKGROUND: An equivocal literature exists regarding the relation between persistent organochlorine pollutants (POPs) and endometriosis in women, with differences attributed to methodologies.

OBJECTIVES: We assessed the association between POPs and the odds of an endometriosis diagnosis and the consistency of findings by biological medium and study cohort.

METHODS: Using a matched cohort design, we assembled an operative cohort of women 18-44 years of age undergoing laparoscopy or laparotomy at 14 participating clinical centers from 2007 to 2009 and a population-based cohort matched on age and residence within a 50-mile catchment area of the clinical centers. Endometriosis was defined as visualized disease in the operative cohort and as diagnosed by magnetic resonance imaging in the population cohort. Logistic regression analysis was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for each POP in relation to an endometriosis diagnosis, with separate models run for each medium (omental fat in the operative cohort, serum in both cohorts) and cohort. Adjusted models included age, body mass index, breast-feeding conditional on parity, cotinine, and lipids.

RESULTS: Concentrations were higher in omental fat than in serum for all POPs. In the operative cohort, γ-hexachlorocyclohexane (γ-HCH) was the only POP with a significant positive association with endometriosis [per 1-SD increase in log-transformed γ-HCH: adjusted OR (AOR) = 1.27; 95% CI: 1.01, 1.59]; β-HCH was the only significant predictor in the population cohort (per 1-SD increase in log-transformed β-HCH: AOR = 1.72; 95% CI: 1.09, 2.72).

CONCLUSIONS: Using a matched cohort design, we found that cohort-specific and biological-medium-specific POPs were associated with endometriosis, underscoring the importance of methodological considerations when interpreting findings.

Abstract  To determine the possible neurotoxic impact of prenatal exposure to polychlorinated biphenyls (PCBs), we analyzed banked cord blood from a Faroese birth cohort for PCBs. The subjects were born in 1986-1987, and 917 cohort members had completed a series of neuropsychological tests at age 7 years. Major PCB congeners (118, 138, 153, and 180), the calculated total PCB concentration, and the PCB exposure estimated in a structural equation model showed weak associations with test deficits, with statistically significant negative associations only with the Boston Naming test. Likewise, neither hexachlorobenzene nor p,p'-dichlorodiphenyldichloroethylene showed clear links to neurobehavioral deficits. Thus, these associations were much weaker than those associated with the cord-blood mercury concentration, and adjustment for mercury substantially attenuated the regression coefficients for PCB exposure. When the outcomes were joined into motor and verbally mediated functions in a structural equation model, the PCB effects remained weak and virtually disappeared after adjustment for methylmercury exposure, while mercury remained statistically significant. Thus, in the presence of elevated methylmercury exposure, PCB neurotoxicity may be difficult to detect, and PCB exposure does not explain the methylmercury neurotoxicity previously reported in this cohort.

Abstract  Polychlorinated biphenyls (PCBs) are synthetic chemicals primarily used as coolants and insulators in electrical equipment. Although banned for several decades, PCBs continue to exist in the environment because of their long half-life, continued presence in items produced before the ban, and poor disposal practices. Epidemiological and experimental studies have identified exposure to PCBs as a potential risk factor for Parkinson's disease, perhaps more so in females. The objective of this work was to examine the association between PCB levels in post-mortem human brain tissue and the diagnosis of Parkinson's disease, as well as the degree of nigral depigmentation. We also sought to determine if this association was more significant when patients were stratified by sex. Post-mortem brain samples from control patients and those diagnosed with Parkinson's disease were obtained from the Emory University Brain Bank and from the Nun Study. Concentrations of eight prevalent PCB congeners were extracted from post-mortem brain tissue and analyzed using gas chromatography-mass spectrometry. PCB congeners 153 and 180 were significantly elevated in the brains of Parkinson's disease patients. When stratified by sex, the female Parkinson's disease group demonstrated significantly elevated concentrations of total PCBs and specifically congeners 138, 153, and 180 compared to controls, whereas PCB concentrations in males were not significantly different between control and Parkinson's disease groups. In a separate population of women (Nun Study) who had no clinical signs or symptoms of PD, elevated concentrations total PCB and congeners 138, 153 and 180 were also observed in post-mortem brain tissue exhibiting moderate nigral depigmentation compared to subjects with mild or no depigmentation. These quantitative data demonstrate an association between brain PCB levels and Parkinson's disease-related pathology. Furthermore, these data support epidemiological and laboratory studies reporting a link between PCB exposure and an increased risk for Parkinson's disease, including greater susceptibility of females.

Abstract  Polychlorinated biphenyls (PCBs) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) are suspected reproductive toxicants. We assessed serum concentration of 76 PCB congeners, DDE, and risk of human chorionic gonadotropin confirmed pregnancy loss among 79 women followed for up to 12 menstrual cycles or until pregnancy. 55 women had live births, 14 experienced pregnancy losses, and 10 did not achieve pregnancy. PCBs and DDE were quantified using gas chromatography with electron capture. PCBs were grouped a priori by biologic activity. Cox proportional hazard regression adjusting for age (categorized 24 - 29, 30 - 34) and average standardized alcohol and cigarette intake (continuous) was used to estimate hazard ratios (HR) of pregnancy loss. Estrogenic PCBs (HR = 1.66, 95% CI: 0.68, 4.02), anti-estrogenic PCBs (HR = 0.10, 95% CI: <0.01, 67.07) and DDE (HR = 1.43, 95% CI: 0.45, 4.52) were not statistically significantly associated with pregnancy loss. Our results provide some signal that estrogenic and antiestrogenic PCBs may be differentially associated with pregnancy loss. Further research is needed to elucidate these associations.

Abstract  EIS: Epidemiology Information System

Abstract  BACKGROUND: Prenatal exposure to environmental levels of organochlorines (OCs) has been demonstrated to have immunotoxic effects in humans. We investigated the relationship between prenatal exposure to OCs and the occurrence of otitis media (OM) among Inuit children in Greenland.

METHODS: We estimated the concentration of 14 PCB congeners and 11 pesticides in maternal and cord blood samples and in breast milk in a population-based cohort of 400 mother-child pairs. At follow-up, we examined the children's ears and used their medical records to assess the OM occurrence and severity. Multivariate regression analyses were used with adjustments for passive smoking, crowding, dietary habits, parent's educational level, breast feeding and the use of child-care.

RESULTS: The children were 4-10 years of age at follow-up and 223 (85%) participated. We found no association between prenatal OC exposure and the development of OM. Factors associated with the child's hazard of OM during the first 4 years of life were: mother's history of OM (HR 1.70, 95% CI 1.11-2.59, p=0.01); mother's smoking habits: current (HR 2.47, 95% CI 1.45-4.21, p<0.01) and previous (HR 2.00, 95% CI 1.19-3.36, p<0.01); number of smokers in the home (HR 1.17, 95% CI 1.05-1.31, p<0.01). After adjustment mothers' smoking habits remained significant.

CONCLUSION: We found no relationship between high levels of prenatal exposure of OCs and occurrence of OM. Passive smoking was found as the strongest environmental risk factor for the development of OM. Interventions to reduce passive smoke in children's environment are needed.

Abstract  BACKGROUND: People in developed countries are widely exposed to low levels of organochlorine pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs). Seafood is a major contributor to PCB exposure. Toxicity of those various pollutants to reproductive and endocrine functions raises questions about possible effects on fertility. We explored whether serum levels of these pollutants and seafood consumption were associated with the fertility of couples enrolled in a French birth cohort (PELAGIE).

METHODS: Time-to-pregnancy was investigated in 3,421 pregnant women by asking how many months they had taken to conceive. Levels of 14 organochlorine pesticides, 12 PCBs, and 10 PBDE compounds were measured in cord blood serum from a random subcohort (n = 394). Mercury concentrations measured in maternal hair were considered as a potential coexposure. Fecundability odds ratios (ORs) were estimated from multivariate discrete-time Cox proportional hazard models.

RESULTS: Shellfish consumption was associated with longer time-to-pregnancy (fecundability OR ≥twice/week vs. <twice/month = 0.71 [95% confidence interval = 0.60-0.83]), but fish consumption was not. Time-to-pregnancy increased with increasing serum levels for most of the compounds studied (for total PCBs >0.410 µg/L vs. <0.266 µg/L, fecundability OR = 0.46 [0.32-0.66]). In multiple sensitivity analyses, reduced fecundability was most consistently associated with shellfish consumption, p,p'-DDE, total PCBs, PCB153, and PCB187. Models that simultaneously included multiple coexposure factors led to similar conclusions.

CONCLUSIONS: Our findings were robust in sensitivity analyses, including analysis restricted to primiparous women. These results suggest that PCBs, p,p'-DDE, and other shellfish contaminants may impair human fertility.

Abstract  OBJECTIVES: The purpose of this study was to investigate the associations between serum concentrations of hydroxylated PCBs (OH-PCBs) and PCBs and measures of thyroid hormone status of Japanese pregnant women.

METHODS: The concentrations of free thyroxine (fT4), thyroid stimulating hormone (TSH), and thyroxine binding globulin (TBG) as well as 16 OH-PCB isomers and 29 PCB isomers were analyzed in the serum of 129 women sampled in the first trimester of gestation. Dietary and lifestyle information of the subjects was obtained by self-administered questionnaire. Multiple regression analysis was performed using measures of thyroid hormones as the dependent variable and serum levels of OH-PCBs/PCBs, urinary iodine concentration, and other potential covariates (age, BMI, smoking, etc.) as independent variables.

RESULTS: Geometric mean (GM) concentration of the sum of 16 isomers of OH-PCBs was 120 pg/g wet wt. and that of 29 isomers of PCBs was 68 ng/g lipid wt., respectively, in the serum of the subjects. Iodine nutrition was considered adequate to high from urinary iodine level (GM, 370 μg/g creatinine). The mean concentration of TSH, fT4 and TBG was 1.34 ± 1.37 μIU/mL, 1.22 ± 0.16 ng/dL and 33.0 ± 6.4 μg/mL, respectively, with a small number of subjects who were outside the reference range. Multiple regression analysis revealed that serum concentrations of OH-PCBs/PCBs were not significantly associated with any of the measures of thyroid hormone status.

CONCLUSIONS: Exposure/body burden of OH-PCBs and PCBs at environmental levels does not have a measurable effect on thyroid hormones.

Abstract  Breast cancer is responsible for considerable morbidity and the majority of female deaths in industrialized countries. In the etiology of breast cancer many endogenous and exogenous risk factors have been discussed. It is estimated that about 40% of all cancers in women are hormonally mediated. Both estrogens and androgens play critical roles in the development of breast cancer, which has been confirmed by numerous epidemiologic data on the levels of serum and urine hormons in populations at low and high risk, as well as by case-control and cohort studies. Estrogen carcinogenesis is attributed to receptor-mediated growth and proliferation of breast epithelial cells and to DNA impairment caused by activated estrogen metabolites, e.g., catechol estrogens and free radicals. In the last decade, the organochlorine chemicals, which include pesticides, polychlorinated biphenyl congeners and other representatives of the dioxin family, have been regarded as xenoestrogens. These chemicals are capable of modulating hormonally regulated processes and inducing changes in growth factors that may be responsible for carcinogenic effect. Many case-control studies have shown the distinct association between breast adipose tissue concentrations of several organochlorine xenoestrogens and breast cancer risk. Also in some studies, the women with breast cancer had higher organochlorine levels in serum as compared with controls.

Abstract  Some reports indicate that exposure to specific polychlorinated biphenyl (PCB) congeners is related to breast cancer risk. The authors recruited participants in a case-control study from October 1994 to March 1997 to assess the relation between breast cancer risk and concentrations of 14 PCB congeners measured in plasma lipids by high-resolution gas chromatography. Participants were incident cases of breast cancer (n = 314) and controls (n = 523) from the Quebec City region (Canada). Compared with controls, cases had significantly higher concentrations of PCB 99 (p = 0.02), PCB 118 (p = 0.03), and PCB 156 (p = 0.006). Associations were found between breast cancer risk and either PCB 118 (odds ratio (OR) = 1.60, 95% confidence interval (CI): 1.01, 2.53; fourth vs. first quartile) or PCB 156 (OR = 1.80, 95% CI: 1.11, 2.94; fourth vs. first quartile) concentration. Breast cancer risk was also associated with a total concentration of the three mono-ortho-substituted congeners 105, 118, and 156 expressed as 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents (OR = 2.02, 95% CI: 1.24, 3.28; fourth vs. first quartile). These results suggest that exposure to dioxin-like PCBs increases breast cancer risk. Alternatively, the results may be explained by differences between cases and controls regarding metabolic pathways involved in the biotransformation of both mono-ortho PCBs and estrogens.

Abstract  Several organochlorines identified as "hormone mimics" were proposed as possible risk factors for breast cancer. We conducted a case-control study to assess breast cancer risk and disease aggressiveness in relation to plasma concentrations of several organochlorine compounds. Plasma lipid concentrations of 11 chlorinated pesticides and 14 polychlorinated biphenyl congeners were measured in 315 women newly diagnosed with breast cancer, 219 hospital-based controls, and 307 population controls from the Quebec City area (Canada). Concentrations of hormonally active organochlorines or their surrogates were compared between cases and controls as well as between groups of cases defined according to tumor size and axillary-lymph-node involvement. We found similar levels of organochlorines in cases and controls and no relationship between the relative risk of breast cancer and organochlorine exposure. However, the probability of lymph-node invasion among cases increased with exposure to 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene [p,p'-DDE; odds ratio, 2.54; 95% confidence interval (CI), 1.20-5.35; between the highest and the lowest tertiles]. Furthermore, p,p'-DDE exposure was associated with a dose-related increased relative risk of exhibiting both lymph-node involvement and a large tumor. Indeed odds ratio raised to 2.33 (95% CI, 0.94-5.77) for the second tertile relative to the first tertile and reached 3.51 (95% CI, 1.41-8.73) for the third tertile relative to the first tertile. Similar associations were noted with beta-hexachlorocyclohexane, oxychlordane, and transnonachlor. We conclude that exposure to persistent, hormonally active organochlorines during adulthood is not associated with breast cancer risk. The possibility that some organochlorines and especially p,p'-DDE may increase breast cancer aggressiveness deserves further attention.

Abstract  BACKGROUND: Persistent organochlorine pollutants (POP), such as polychlorinated biphenyls (PCB) and dichlorodiphenyldichloroethylene (p, p'-DDE), are widely found in the environment and considered potential endocrine-disrupting compounds (EDC). Their impact on male fertility is still unknown.

METHODS: To explore the hypothesis that POP is associated with altered sperm chromatin integrity, a cross-sectional study involving 707 adult males (193 Inuits from Greenland, 178 Swedish fishermen, 141 men from Warsaw, Poland, and 195 men from Kharkiv, Ukraine) was carried out. Serum levels of 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153), as a proxy of the total PCB burden, and of p,p'-DDE were determined. Sperm chromatin structure assay (SCSA) was used to assess sperm DNA/chromatin integrity.

RESULTS: We found a strong and monotonically increasing DNA fragmentation index with increasing serum levels of CB-153 among European but not Inuit men, reaching a 60% higher average level in the highest exposure group. No significant associations were found between SCSA-derived parameters and p, p'-DDE serum concentrations.

CONCLUSION: These results suggest that human dietary PCB exposure might have a negative impact on the sperm chromatin integrity of adult males but additional issues, including differences in the genetic background and lifestyle habits, still need to be elucidated.

Abstract  The purpose of this study was to investigate possible associations between concentrations of hydroxylated PCBs (OH-PCBs) and PCBs in the serum of women in the first trimester of pregnancy and thyroid hormone levels and body size of newborn infants in 79 mother-neonate pairs. We measured 16 OH-PCB isomers and 29 PCB isomers in the serum of Japanese women sampled at 11.1±1.9 weeks of gestation. The concentrations of free thyroxine (fT4) and thyroid stimulating hormone (TSH) were measured in whole blood spots on filter papers sampled from the neonates. Dietary and lifestyle information of the mothers were obtained by self-administered questionnaires. Geometric mean (GM) concentrations of the sum of 16 OH-PCB isomers and of 29 PCB isomers were 1.2×10(2)pg/g wet wt. and 69ng/g lipid wt., respectively, in maternal serum. The GM concentrations of neonatal fT4 and TSH were 2.21ng/dL and 1.37μIU/mL, respectively. Multiple regression analysis was performed using measures of neonatal thyroid hormones as dependent variable and serum levels of OH-PCBs/PCBs and other potential covariates (age, pre-pregnancy weight, smoking status, etc.) as independent variables. The results demonstrated a significant positive association between the concentrations of some OH-PCB isomers and that of neonatal TSH. There were no significant associations between levels of PCBs and neonatal fT4, or between OH-PCBs/PCBs and body size of neonates. We conclude that exposure to/body burden of OH-PCBs, but not PCBs, at environmental levels during the first trimester of pregnancy can affect neonatal thyroid hormone status.

Abstract  Maternal diet not only provides essential nutrients to the developing fetus but is also a source of prenatal exposure to environmental contaminants. We investigated the association between dietary intake of dioxins and PCBs during pregnancy and birth size. The study included 50,651 women from the Norwegian Mother and Child Cohort Study (MoBa). Dietary information was collected by FFQs and intake estimates were calculated by combining food consumption and food concentration of dioxins, dioxin-like PCBs and non-dioxin-like PCBs. We used multivariable regression models to estimate the association between dietary intake of dioxins and PCBs and fetal growth. The contribution of fish and seafood intake during pregnancy was 41% for dietary dioxins and dioxin-like PCBs and 49% for dietary non-dioxin-like PCBs. Further stratified analysis by quartiles of seafood intake during pregnancy was conducted. We found an inverse dose-response association between dietary intake of dioxins and PCBs and fetal growth after adjustment for confounders. Newborns of mothers in the upper quartile of dioxin and dioxin-like PCBs intake had 62g lower birth weight (95% CI: -73, -50), 0.26cm shorter birth length (95% CI: -0.31, -0.20) and 0.10cm shorter head circumference (95% CI: -0.14, -0.06) than newborns of mothers in the lowest quartile of intake. Similar negative associations for intake of dioxins and dioxin-like PCBs were found after excluding women with intakes above the tolerable weekly intake (TWI=14pg TEQ/kg bw/week). The negative association of dietary dioxins and PCBs with fetal growth was weaker as seafood intake was increasing. No association was found between dietary dioxin and PCB intake and the risk for small-for-gestational age neonate. In conclusion, dietary intakes of dioxins and PCBs during pregnancy were negatively associated with fetal growth, even at intakes below the TWI.

Abstract  Persistent organic pollutants such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (OCPs) are of global concern because of their widespread contamination and adverse health effects. Potential endocrine disruption, especially of thyroid status by PCBs has been repeatedly suggested in both experimental and epidemiological studies. However the associations with PBDEs or OCPs have been arguable especially in human populations. We investigated the associations between major groups of POPs and thyroid hormone balances among pregnant women. One hundred five pregnant women at delivery were recruited from four cities of Korea in 2011 and were investigated. Blood samples were collected within a day before delivery. Serum was then analyzed for 19 PCBs, 19 PBDEs, and 19 OCPs, along with five thyroid hormones (free and total T3 and T4, and TSH). Several PCBs such as PCB28, 52, and 118 showed negative associations with T3 or T4. BDE47 and total PBDEs showed significant associations with T3 or T4. For OCPs, dichlorodiphenyltrichloroethanes (DDTs) and hexachlorobenzene (HCB) were generally associated with reduction of T3 or T4. The thyroid hormone levels of all subjects were within the reference range, however exposure to several target POPs were clearly related with potential for disrupting thyroid hormone balance among pregnant women, at the current level of exposure. Although subtle, the changes in thyroid hormones should be seen with caution because even minor changes within pregnant women may have significant consequences especially on sensitive population like fetus.