Association of prenatal exposure to PCDD/Fs and PCBs with maternal and infant thyroid hormones: The Hokkaido Study on Environment and Children's Health

Abstract

Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs) are persistent organic pollutants that are universally detected. Some congeners of PCDDs, PCDFs or PCBs have dioxin-like toxicity, whereas non-dioxin-like PCBs are considered to have different toxicity. Reports of the relationships between prenatal exposure to PCDDs, PCDFs or PCBs and thyroid homeostasis in pregnant women and infants have been inconsistent. The aim of this study was to investigate the effect of maternal serum PCDD/F or PCB levels on maternal and neonatal thyroid hormone (TH) levels in a prospective cohort. Of the 514 subjects in the prospective cohort, 386 mothers and 410 infants were included for analysis. Fifteen dioxins and seventy PCBs in maternal blood collected between 23 and 41weeks of gestation were measured using high-resolution gas chromatography and high-resolution mass spectrometry. Blood samples to measure thyroid stimulating hormone (TSH) and free thyroxine (FT4) levels were obtained from mothers at an early gestational stage (median ten weeks), and from infants between four and seven days of age, respectively. Multiple linear regression analysis was conducted. Median concentration of total PCBs, PCB 153 were 104,700, and 20,500pg/g lipid, respectively. Median total dioxin-TEQ was 13.8pg/g lipid. Total dioxin-TEQ, coplanar PCBs were positively associated with neonatal FT4 (beta=0.224, 0.206, respectively). The association was stronger in boys (beta=0.299, 0.282, respectively). Several PCDD/F and PCB isomers were also positively associated with neonatal FT4. Total PCBs or non-dioxin-like PCBs were not associated with any maternal or neonatal THs. No DLC grouping or congeners were associated with neonatal TSH. Non-ortho PCBs were positively associated with maternal FT4. Three PCB congeners had significant positive association(s) with maternal THs. In conclusion, the results of our study suggest that perinatal exposure to background-level DLCs increases neonatal FT4, especially in boys.

Polychlorinated Biphenyls (PCBs): Risk Factors for Autism Spectrum Disorder?

“…Similar results have been reported in countries around the world. Analysis of PCB levels in blood from pregnant women in two different Japanese cohorts reported the sum total PCBs (13 examined) of 17.8–362 ng/g lipid [ 52 ], and 20–210 ng/g lipid (29 congeners examined [ 53 ]. Median levels of PCB 153, widely used as an indicator PCB, in the serum of pregnant mothers in Greenland were 107 ng/g lipid [ 42 ], while, in the Ukraine, they were 27 ng/g lipid; the latter was associated with cognitive defects in the children [ 54 ].…”

Association of maternal serum concentration of hydroxylated polychlorinated biphenyls with maternal and neonatal thyroid hormones: The Hokkaido birth cohort study

“…Since Japanese people intake more than 80 % of the PCBs via seafood, it is assumed that OH-PCB profiles in our participants are mainly derived from seafood (Mori et al 2014). The concentrations of precursors of 4-OH-CB187, PCB-183 and PCB-187 (measured as PCB-182 and 187), were 1.6 and 5.8 ng/g lipid weight, respectively among participants in this study, which were predominant PCBs with rather high levels compared to other PCBs in our earlier study (Baba et al 2018). Conversely, 4-OH-CB107, which has been reported as one of the main OH-PCB isomers, was detected only in 47.3 % of serum samples.…”

“…Our previous study reported the absence of an association between maternal PCB levels and maternal and neonatal THs (Baba et al 2018). However, current study suggested that OH-PCBs may have effects on fetal thyroid functions than PCBs.…”

“…Conversely, 4-OH-CB107, which has been reported as one of the main OH-PCB isomers, was detected only in 47.3 % of serum samples. While most of the OH-PCBs present in human blood are generated from PCBs, our earlier study examined maternal exposure to PCB-105 and 118 (precursors of 4-OH-CB-107) at rather high levels (Baba et al 2018). In addition to the different concentrations of PCB precursors, the differences in OH-PCB profiles may be explained by the metabolic capacities by different CYP enzymes (Grimm et al 2015).…”

The potential disruption of estrogen and androgen homeostasis and adipocyte differentiation by metabolites of common airborne polychlorinated biphenyls

“…PCBs have been reported to be positively associated with alteration of maternal thyroid hormones [58]. Other effects on the reproductive systems depend upon the individual PCBs and their concentrations within the mixture [59].…”