Association between Several Persistent Organic Pollutants and Thyroid Hormone Levels in Cord Blood Serum and Bloodspot of the Newborn Infants of Korea

<div><p>Current knowledge on adverse endocrine disruption effects of persistent organic pollutants (POPs) among newborn infants is limited and often controversial. To investigate the associations between prenatal exposure to major POPs and thyroid hormone levels among newborn infants, both cord serum or maternal serum concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (OCPs) were compared with five thyroid hormones in cord serum of newborn infants as well as TSH in bloodspot collected at 2 day after birth (n=104). Since cord serum thyroid hormones could be affected by those of mothers, thyroid hormone concentrations of the matching mothers at delivery were adjusted. In cord serum, BDE-47, -99, and Σchlordane (CHD) showed significant positive associations with cord or bloodspot TSH. At the same time, <i>p</i>,<i>p'</i>-dichlorodiphenyldichloroethylene (<i>p</i>,<i>p'</i>-DDE) and hexachlorbenzene (HCB) showed negative associations with total T3 and total T4 in cord serum, respectively. Maternal exposure to <i>β</i>-hexachlorhexane (<i>β</i>-HCH), ΣCHD, ΣDDT, or <i>p</i>,<i>p'</i>-DDE were also associated with neonatal thyroid hormones. Although the sample size is small and the thyroid hormone levels of the subjects were within the reference range, our observation supports thyroid disrupting potential of several POPs among newborn infants, at the levels occurring in the general population. Considering the importance of thyroid hormones during gestation and early life stages, health implication of thyroid hormone effects by low level POPs exposure deserves further follow up investigations.</p></div

Associations between prenatal POPs concentrations in either maternal or cord blood and thyroid hormone levels of newborn infants.

<p>‘-’ no association;</p><p>‘↑’ positive association;</p><p>‘↓’ negative association (p<0.05);</p><p>Blank cell means data not available. ‘fT3’ free T3; ‘TT3’ total T3; ‘fT4’ free T4; ‘TT4’ total T4. In the present study, cord thyroid hormone levels were adjusted with maternal thyroid hormone levels in the model. Unless otherwise noted, all thyroid hormone measurements were from cord blood or cord serum. ‘s’ indicates the measurement in bloodspot of newborn infant.</p><p>Associations between prenatal POPs concentrations in either maternal or cord blood and thyroid hormone levels of newborn infants.</p

Gender- and Age-Group Specific Association of Persistent Organic Pollutants (POPs) Exposure with Diabetes Mellitus: Korean National Environmental Health Survey (KoNEHS) 2015–2017

Exposure to persistent organic pollutants (POPs) has been reported as a potential risk factor for diabetes in adults. However, effect modifications by sex and age, especially among Asian populations, have seldom been investigated. In the present study, we assessed associations of major POPs exposure including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs), with diabetes in Korean adults (n = 1,295), a subset of the Korean National Environmental Health Survey (KoNEHS) Cycle 3 (2015–2017). In the adult population, serum levels of dichlorodiphenyltrichloroethanes (DDTs) and PCB167 showed an increased odds ratio (OR) for diabetes. When stratified by gender, associations became stronger and more consistent in women: In women, serum levels of OCPs including p,p′-DDT, p,p′-dichlorodiphenyldichloroethylene (p,p′-DDE), and ΣOCPs and mono-ortho PCBs, such as PCB118 and PCB157, were significantly associated with diabetes. In the male participants, however, no significant positive associations were detected. When stratified by a cutoff age of 50 years, most studied POPs except PBDEs, i.e., p,p′-DDT, p,p′-DDE, PCB118, PCB157, PCB167, PCB138, and PCB153, showed significant associations with diabetes, in the older adults. In the younger group, however, no measured POPs showed a significant positive association. Effects of endogenous sex hormones or interaction of POPs on aryl hydrocarbon receptors may partly explain the observed differences by gender and age, although further experimental confirmations should follow. Our findings show that POPs exposure at the current levels is associated with diabetes among general Korean adults, and such associations could be modified by gender and age

Characteristics of the study population.

<p>^a Normal spontaneous vaginal delivery.</p><p>^b Caesarean section.</p><p>^c Bloodspot TSH was measured from bloodspot samples collected at day 2–7 post-partum. Most newborn babies were collected for bloodspot on day 2 (within 48 hrs) post-partum, but 3 and 2 infants were collected on day 5 and 7 post-partum, respectively.</p><p>Characteristics of the study population.</p

Associations between POPs concentrations in maternal blood and thyroid hormone levels in cord blood serum or in bloodspot of newborn infant population in Korea (n = 104).

<p>Signs * and ^ indicate statistical significance of regression parameter at p<0.05, and 0.1, respectively. All POPs concentrations and thyroid hormone levels were natural log—transformed. Results of association regarding free T3, total T3, free T4, total T4, and TSH were adjusted for age, gestation period, mode of delivery, parity, pre-pregnancy BMI, smoking status during pregnancy, and maternal weight gain during pregnancy. While infant sex was added as covariate and smoking status was removed for analysis of bloodspot TSH. Chemicals that were detected > = 75% of the population at concentrations greater than the limit of quantification, a proxy value of ‘limit of quantification divided by square root 2’ was used. For chemicals that were detected in <75% but > = 60%, statistical analysis was conducted with detected values only. Such chemicals are indicated by ‘+’. Since BDE-99 were detected below 60% in maternal serum samples, they were not statistically analyzed.</p><p>Associations between POPs concentrations in maternal blood and thyroid hormone levels in cord blood serum or in bloodspot of newborn infant population in Korea (n = 104).</p

Associations between serum POPs concentrations and thyroid hormones in the sensitivity analysis.

<p>Signs * and ^ indicate statistical significance of regression parameter (β) at p<0.05, and 0.1, respectively. ‘CI’ confidence interval; ‘fT3’ free T3; ‘TT3’ total T3; ‘fT4’ free T4. For the calculation of association, two or more independent variables that were determined as significant predictors to a given thyroid hormone, and at the same time were correlated each other, were added in the multiple regression analysis, in order to identify major predictors. In the regression model, interaction terms between the selected POPs were not included.</p><p>Associations between serum POPs concentrations and thyroid hormones in the sensitivity analysis.</p

Association between Several Persistent Organic Pollutants in Serum and Adipokine Levels in Breast Milk among Lactating Women of Korea

Exposure to several persistent organic pollutants (POPs) has been linked to alteration of lipid metabolism. Adipokines, such as leptin and adiponectin, are hormones that play roles in lipid metabolism, and have been suggested as markers of health effects that may lead to obesity. To date, only serum adipokines have been associated with POPs exposure. In the present study, for the first time, the associations between leptin and adiponectin in breast milk, and several POPs in serum were investigated among 82 lactating Korean women between 25 and 46 years of age. Breast milk adipokines are important because adipokine intake of infant through breastfeeding may influence the growth of infants. The median concentrations of leptin and adiponectin in skimmed milk of the Korean lactating women were 17.9 ng/L and 16.5 μg/L, respectively. Leptin concentrations in breast milk were negatively associated with ∑hexachlorohexane (HCH), oxychlordane, ∑chlordane, or 2,2′,4,4′,5,5′-hexachlorobiphenyl (CB 153) levels in maternal serum. Linear relationships between adiponectin and POPs concentrations were not observed, however, nonmonotonic relationship which showed generally positive associations was suggested for <i>p</i>,<i>p</i>′-dichlorodiphenyltrichloroethane (DDT) and ∑chlordane in quartile analysis. Our observations show that POPs at the current level of exposure may be associated with the alteration of lipid metabolism among lactating women. Implication of adipokine transfer to breastfed infants is of concern and deserves further investigation

Two Years after the <i>Hebei Spirit</i> Oil Spill: Residual Crude-Derived Hydrocarbons and Potential AhR-Mediated Activities in Coastal Sediments

The <i>Hebei Spirit</i> oil spill occurred in December 2007 approximately 10 km off the coast of Taean, South Korea, on the Yellow Sea. However, the exposure and potential effects remain largely unknown. A total of 50 surface and subsurface sediment samples were collected from 22 sampling locations at the spill site in order to determine the concentration, distribution, composition of residual crudes, and to evaluate the potential ecological risk after two years of oil exposure. Samples were extracted and analyzed for 16 polycyclic aromatic hydrocarbons (PAHs), 20 alkyl-PAHs, 15 aliphatic hydrocarbons, and total petroleum hydrocarbons using GC-MSD. AhR-mediated activity associated with organic sediment extracts was screened using the H4IIE-<i>luc</i> cell bioassay. The response of the benthic invertebrate community was assessed by mapping the macrobenthic fauna. Elevated concentrations of residual crudes from the oil spill were primarily found in muddy bottoms, particularly in subsurface layers. In general, the bioassay results were consistent with the chemistry data in a dose-dependent manner, although the mass-balance was incomplete. More weathered samples containing greater fractions of alkylated PAHs exhibited greater AhR activity, due to the occurrence of recalcitrant AhR agonists present in residual oils. The macrobenthic population distribution exhibits signs of species-specific tolerances and/or recolonization of certain species such as <i>Batillaria</i> during weathering periods. Although the <i>Hebei Spirit</i> oil spill was a severe oil exposure, it appears the site is recovering two years later