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Abstract Background Polychlorinated biphenyls (PCBs) are ubiquitous environmental toxins. Although there is growing evidence to support an association between PCBs and deficits of neurodevelopment, the specific mechanisms are not well understood. The potentially different roles of specific PCB groups defined by chemical structures or hormonal activities e.g., dioxin-like, non-dioxin like, or anti-estrogenic PCBs, remain unclear. Our objective was to examine the association between prenatal exposure to defined subsets of PCBs and neurodevelopment in a cohort of infants in eastern Slovakia enrolled at birth in 2002-2004. Methods Maternal and cord serum samples were collected at delivery, and analyzed for PCBs using high-resolution gas chromatography. The Bayley Scales of Infant Development -II (BSID) were administered at 16 months of age to over 750 children who also had prenatal PCB measurements. Results Based on final multivariate-adjusted linear regression model, maternal mono-ortho-substituted PCBs were significantly associated with lower scores on both the psychomotor (PDI) and mental development indices (MDI). Also a significant association between cord mono-ortho-substituted PCBs and reduced PDI was observed, but the association with MDI was marginal (p = 0.05). Anti-estrogenic and di-ortho-substituted PCBs did not show any statistically significant association with cognitive scores, but a suggestive association between di-ortho-substituted PCBs measured in cord serum and poorer PDI was observed. Conclusion Children with higher prenatal mono-ortho-substituted PCB exposures performed more poorly on the Bayley Scales. Evidence from this and other studies suggests that prenatal dioxin-like PCB exposure, including mono-ortho congeners, may interfere with brain development in utero. Non-dioxin-like di-ortho-substituted PCBs require further investigation.

BACKGROUND: Despite experimental evidence that lactational exposure to persistent organic pollutants (POPs) can impact health, results from epidemiologic studies are inconclusive. Inconsistency across studies may reflect the inability of current [...]

OBJECTIVE: Our aim in the present study was to characterize and quantify the levels of polychlorinated biphenyls (PCBs) and specific polychlorobiphenylol (OH-PCB) metabolites in maternal sera from women delivering in [...]

Background: Polychlorinated biphenyls (PCBs) are ubiquitous environmental toxins. Although there is growing evidence to support an association between PCBs and deficits of neurodevelopment, the specific mechanisms are not well understood. The potentially different roles of specific PCB groups defined by chemical structures or hormonal activities e.g., dioxin-like, non-dioxin like, or anti-estrogenic PCBs, remain unclear. Our objective was to examine the association between prenatal exposure to defined subsets of PCBs and neurodevelopment in a cohort of infants in eastern Slovakia enrolled at birth in 2002-2004. Methods: Maternal and cord serum samples were collected at delivery, and analyzed for PCBs using highresolution gas chromatography. The Bayley Scales of Infant Development -II (BSID) were administered at 16 months of age to over 750 children who also had prenatal PCB measurements. Results: Based on final multivariate-adjusted linear regression model, maternal mono-ortho-substituted PCBs were significantly associated with lower scores on both the psychomotor (PDI) and mental development indices (MDI). Also a significant association between cord mono-ortho-substituted PCBs and reduced PDI was observed, but the association with MDI was marginal (p = 0.05). Anti-estrogenic and di-ortho-substituted PCBs did not show any statistically significant association with cognitive scores, but a suggestive association between di-ortho-substituted PCBs measured in cord serum and poorer PDI was observed. Conclusion: Children with higher prenatal mono-ortho-substituted PCB exposures performed more poorly on the Bayley Scales. Evidence from this and other studies suggests that prenatal dioxin-like PCB exposure, including mono-ortho congeners, may interfere with brain development in utero. Non-dioxin-like di-ortho-substituted PCBs require further investigation. [ABSTRACT FROM AUTHOR]

Background: Hydroxylated polychlorinated biphenyls (OH-PCBs), unlike PCBs, are in general readily excreted yet are still detected in humans and animals. Active transport of OH-PCBs across the placenta and hydroxylation of PCBs by the fetus suggest the potential for greater impact on the fetus compared with the parent PCB compounds, but little is known about their health effects, particularly in humans. Objectives: The objective of this study was to evaluate the associations between prenatal OH-PCB exposure and neurodevelopment in children at 16 months of age in eastern Slovakia. Methods: A birth cohort (n = 1,134) was enrolled during 2002-2004. We analyzed six OH-PCB metabolites (4-OH-CB-107, 3-OH-CB-153, 4-OH-CB-146, 3'-OH-CB-138, 4-OH-CB-187, and 4'-OH-CB-172) in a subset of the cohort. The Bayley Scales of Infant Development were administered to the children at the 16-month follow-up visit. We developed multiple linear regression models predicting standardized scores for the Mental Development Index (MDI) and Psychomotor Development Index (PDI) from maternal (n = 147) and cord (n = 80) serum OH-PCB concentrations, adjusting for sex of child, district, HOME (Home Observation for Measurement of the Environment) score, and maternal score on Raven's Progressive Matrices. Results: Cord 4-OH-CB-107 was significantly associated with lower MDI (β = -2.27; p = 0.01) and PDI (β = -4.50; p = 0.004). Also, maternal 4-OH-CB-107 was significantly associated with lower MDI (β = -1.76; p = 0.03) but not PDI. No other OH-PCB metabolites were associated with decreased PDI or MDI. Conclusions: Our findings showed a significant association of 4-OH-CB-107 with decreased MDI, which can possibly be mediated by endocrine disruption, altered neurotransmitter functions, or reduced thyroid hormone concentrations in brain. [ABSTRACT FROM AUTHOR]

Background: Several our previous studies showed associations of increasing blood level of persistent organochlorinated pollutants (POPs) with individual thyroid and metabolic adverse health signs in subjects from heavily polluted area (POLL) compared to these from the area of background pollution (BCGR). In this study we present increasing number of subjects with multiple adverse signs positively associated with blood level of polychlorinated biphenyls (PCBs) which is used as a marker of other POPs cocktail. Methods: In a total of 2046 adults (834 males and 1212 females; age range 21-75) from POLL and BCGR the serum level of major POPs such as of 15 most abundant PCBs congeners, dichlorodiphenyl-dichloroethylene (p,p'-DDE) and hexachlorobenzene (HCB) was estimated by high resolution gas chromatography. In addition, the data on thyroid volume by ultrasound and body mass index were obtained and serum level of thyroperoxidase and thyrotropin receptor antibodies as well as that of free thyroxine, total triiodothyronine, thyrotropin, thyroglobulin, fasting glucose and insulin, cholesterol and triglycerides was measured. Thus, a total of 13 adverse signs were defined and the interrelations between PCBs level and increasing number of subjects with increasing number of adverse signs were evaluated. Results: Because of high correlation between major POPs (PCB, DDE and HCB), for this purpose the level of PCBs was considered as a marker also for the presence of DDE and HCB. Thus, if all data obtained from 2046 subjects were stratified according to quintiles of PCBs level, highly significant increase was found (p < 0.02 to 0.0000 by chi-sqauare) for the frequency of 8 among 13 signs, while the increase of one additional sign was slightly above significance limit and that in 4 other was not significant. Also the number of subjects with multiple adverse signs was significantly higher in POLL than in BCGR. For instance, in BCGR area (1038 subjects; median PCB level of 744 ng/g and 5%-95% range of 423 - 1329 ng/g serum lipids) there were 84 (8.1%) cases with 6 or 7 adverse health signs, while in POLL area (1008 subjects; median PCB level of 1892 ng/g; 5%-95% range of 685 - 9016 ng/g) the prevalence of respective cases was twice as high (195 cases = 19.3%; p < 0.001 by chi-square). For the subjects with the same PCB levels, but with 8 or 9 adverse signs the respective values were 22/1038 (2.1%) vs. 54/1008 (5.3%; p < 0.001). Conclusion: Significantly higher accumulation of adverse signs in subjects with high POPs level was found in POLL thus supporting the conclusion that POPs appear to increase the prevalence of several subclinical and overt thyroid and metabolic disorders. [ABSTRACT FROM AUTHOR]

BACKGROUND: Polychlorinated biphenyls (PCBs) are ubiquitous environmental toxicants, for which animal studies demonstrate immunotoxic effects, including thymic atrophy and suppressed immune responses; human investigations of similar end points are sparse. The thymus is essential for the differentiation and maturation of T-cell lymphocytes. OBJECTIVES: The objective of this study was to examine the association between prenatal PCB exposures and estimated thymus volume in infants from eastern Slovakia, a region where PCBs were produced until 1984. METHODS: Mothers were enrolled at delivery, and maternal blood samples were collected for analysis of 15 PCB congeners, p,p'-DDT [1,1,1-trichloro-2,2'-bis(p-chlorophenyl)ethane], and p,p'-DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene]. Each mother was interviewed to obtain information on sociodemographic characteristics, past pregnancies, occupational history, medication history, and living environment. Neonatal thymus volume was estimated using ultrasound measurements on the third or fourth day after birth. Thymic index was calculated on 982 newborns from mothers with PCB measurements. We developed a predictive model of the natural log of the thymic index using multiple linear regression with covariates selected from the bivariate analyses. RESULTS: Prenatal PCB exposure was associated with a smaller thymic index at birth [β = -36 (natural log-transformed; nanograms per gram lipids); p = 0.047]. District of residence and delivery also predicted thymic index. Male sex, later gestational age, larger birth weight z-score, and Roma ethnicity were associated with a larger thymic index, whereas respiratory illness was associated with a lower thymic index. CONCLUSIONS: This study provides the first evidence to date that PCB exposure in neonates is associated with a smaller thymic volume, suggesting possible impaired immunologic development. [ABSTRACT FROM AUTHOR]