Prenatal and postnatal exposure to polychlorinated biphenyls and child size at 24 months of age

Prenatal exposure to persistent organic pollutants and childhood obesity: A systematic review and meta-analysis of human studies

We conducted a systematic review and meta-analysis of the associations between prenatal exposure to persistent organic pollutants (POPs) and childhood obesity. We focused on organochlorines (dichlorodiphenyltrichloroethane [DDT], dichlorodiphenyldichloroethylene [DDE], hexachlorobenzene [HCB], and polychlorinated biphenyls [PCBs]), perfluoroalkyl and polyfluoroalkyl substances (PFAS), and polybrominated diphenyl ethers (PBDEs) that are the POPs more widely studied in environmental birth cohorts so far. We search two databases (PubMed and Embase) through July/09/2021 and identified 33 studies reporting associations with prenatal organochlorine exposure, 21 studies reporting associations with prenatal PFAS, and five studies reporting associations with prenatal PBDEs. We conducted a qualitative review. Additionally, we performed random-effects meta-analyses of POP exposures, with data estimates from at least three prospective studies, and BMI-z. Prenatal DDE and HCB levels were associated with higher BMI z-score in childhood (beta: 0.12, 95% CI: 0.03, 0.21; I² : 28.1% per study-specific log increase of DDE and beta: 0.31, 95% CI: 0.09, 0.53; I² : 31.9% per study-specific log increase of HCB). No significant associations between PCB-153, PFOA, PFOS, or pentaPBDEs with childhood BMI were found in meta-analyses. In individual studies, there was inconclusive evidence that POP levels were positively associated with other obesity indicators (e.g., waist circumference).

Lactational exposure to polychlorinated biphenyls is higher in overweight /obese women and associated with altered infant growth trajectory: A pilot study

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Human milk levels of PCBs are higher in mothers with overweight and obesity.

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Lactational exposure to PCBs is associated with alterations in development.

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Lactational expsures to PCBs in human milk are associated with slower infant growth patterns.

Background

Infant exposure to environmental chemicals, such as polychlorinated biphenyls (PCBs), may contribute to developmental programming of long-term metabolic disease risk. PCBs persist given their lipophilicity and long half-lives, allowing them to bio-accumulate in adipose tissue. These compounds can then be excreted into maternal milk resulting in infant exposure.

Objective

To determine the level of PCBs in milk from mothers with pre-pregnancy overweight and obese (OW/OB) versus normal weight status (NW) and evaluate the association of milk PCB levels with infant growth over the first 6 months of life.

Methods

A pilot study of a subset of milk samples from mothers with NW (pre-pregnancy body mass index (BMI) < 25 kg/m², n = 11) and OW/OB (pre-pregnancy BMI ≥ 25 kg/m², n = 8) were examined approximately 2-weeks postpartum. PCB congeners 138 + 163, 132 + 153, 180, and the sum were measured using gas chromatography/mass spectrometry and adjusted for milk fat content. Infant growth was monitored from birth to 6 months for weight-for-age (WFA), length-for-age (LFA), weight-for-length (WFL), head circumference-for-age (HCA), and associations with milk PCB content determined using linear mixed modeling.

Results

Total milk fat content did not differ by maternal weight status (p = 0.88). Milk from mothers with OW/OB had significantly higher PCB sum (p = 0.02) and PCB 138 + 163 (p = 0.03). PCB 132 + 153 (β −0.0008, p = 0.0218), PCB 180 (β −0.0010, p = 0.0279), and PCB sum (β −0.0006, p = 0.0138) were negatively associated with HCA Z-score growth to 6 months. PCB 180 was negatively associated with infant WFA (β −0.0015, p = 0.0058) and WFL Z-score (β −0.0016, p = 0.0263) to 6 months. There were no associations of PCB sum content with WFL, LFA, WFL Z-score over the first 6 months of life.

Conclusions

Maternal overweight and obesity are associated with higher levels of total PCB congeners (132, 138, 153, 163, 180) in human milk. PCB congeners have negative associations with infant head circumference and weight trajectory over the first 6 months of life.

Associations of peri-pubertal serum dioxins and polychlorinated biphenyls with growth and body composition among Russian boys in a longitudinal cohort

BACKGROUND

Childhood exposure to organochlorines has been associated with alterations in somatic growth. We evaluated the associations of peri-pubertal serum levels of dioxin-like compounds (DLCs) and nondioxin-like polychlorinated biphenyls (NDL-PCBs), with adolescent growth, body composition, and near adult height (NAH) in a longitudinal cohort study of Russian boys.

METHODS

473 8-9 year-old boys had serum DLCs and associated toxic equivalents (TEQs) and NDL-PCBs concentrations measured. Physical examinations were performed at enrollment between 2003 and 2005, and annually over 11 years to 2016; annual bio-electric impedance analysis (BIA) of body composition began in 2006. We used mixed effects models to evaluate associations of quartiles of serum chemical concentrations with longitudinal measurements through age 19 of body mass index (BMI-Z) and height (HT-Z) z-scores, annual height velocity (HV), and BIA-derived height-adjusted fat (FMi) and fat-free mass (FFMi) indexes. Potential modification by age of the associations of chemical exposures with growth was evaluated. NAH (defined as HV < 1 cm/year) and age at NAH attainment were estimated using parametric survival models accounting for right censoring.

RESULTS

The medians of serum ∑TEQs, ∑DLCs, and ∑NDL-PCBs were 21.1 pg TEQ/g lipid, 362 pg/g lipid, and 250 ng/g lipid, respectively. In multivariable models, higher serum concentrations of peri-pubertal ∑TEQs, ∑DLCs, and ∑NDL-PCBs were associated with significantly lower BMI-Z, FMi, and FFMi over 11 years of follow-up. The differences in FFMi for boys with higher versus lower ΣTEQs and ΣNDL-PCBs increased with age. In multivariable models, higher ∑NDL-PCBs were associated with lower HT-Z, with attenuation of the association with age (interaction p < 0.001). The highest versus the lowest quartiles of ∑NDL-PCBs were not associated with differences in NAH, but were associated with an average of 6 months later attainment of NAH.

CONCLUSIONS

Our findings suggest that dioxin and NDL-PCB exposures during childhood are associated with alterations in body composition and subsequent somatic growth.

Fish, Shellfish, and Children's Health: An Assessment of Benefits, Risks, and Sustainability

American children eat relatively little fish and shellfish in comparison with other sources of animal protein, despite the health benefits that eating fish and shellfish may confer. At the same time, fish and shellfish may be sources of toxicants. This report serves to inform pediatricians about available research that elucidates health risks and benefits associated with fish and shellfish consumption in childhood as well as the sustainability of fish and shellfish harvests.

Featured structure-activity relationships for some tri- and tetrachlorobiphenyls in human CYP2E1-activated mutagenicity - Impact of the extent of ortho-chlorination

Polychlorinated biphenyls (PCBs) as a group of persistent organic pollutants are confirmed human carcinogens; however, their mutagenicity remains mostly unknown. We have reported the mutagenicity of some PCBs with one to four chlorines in mammalian cells expressing human CYP2E1. To further explore the structural requirements for the mutagenicity of PCBs, eight tri- and tetrachlorobiphenyls untested before were investigated for the induction of gene mutations and micronuclei in a V79-derived cell line expressing both human CYP2E1 and sulfotransferase (SULT) 1A1 (V79-hCYP2E1-hSULT1A1), with SULT1A1 activity inhibited by pentachlorophenol, a potent SULT1 inhibitor. 2,2',6-Tri-, 2,3',6-tri, 2,4',6-tri-, and 2,2',5-trichlorobiphenyls (PCBs 19, 27, 32, and 18, respectively) induced micronuclei and gene mutations in V79-hCYP2E1-hSULT1A1 cells, at potencies slightly higher than 2,6-dichlorobiphenyl, but one order of magnitude below that by 2,3,3'- and 2,3,4'-trichlorobiphenyls as reported recently; in the parental V79-Mz cells, they were nonmutagenic and weak in micronuclei induction. Among the four tetrachlorobiphenyls with varying number of ortho chlorines, 2,3,3',4'-tetrachlorobiphenyl (PCB 56) induced both micronuclei and gene mutations in V79-hCYP2E1-hSULT1A1 cells with a potency greater than the above compounds; however, 2,2',3,3'-tetrachlorobiphenyl was equivocal and 2,2',3,6'-tetra- and 2,2',6,6'-tetrachlorobiphenyls inactive in V79-hCYP2E1-hSULT1A1 cells. Immunofluorescent staining of micronuclei formed by PCBs 32 and 56 in V79-hCYP2E1-hSULT1A1 cells with centromere protein B antibodies indicated that they were predominantly whole chromosomes, implying aneugenic potentials. This study suggests that tri- and tetrachlorobiphenyls with a single ortho chlorine can be most mutagenic under activation by human CYP2E1, and greater numbers of ortho chlorines may cause a drastic decline in the activity, especially for tetrachlorobiphenyls.

Infant Dietary Exposures to Environmental Chemicals and Infant/Child Health: A Critical Assessment of the Literature

BACKGROUND

The benefits of breastfeeding to the infant and mother have been well documented. It is also well known that breast milk contains environmental chemicals, and numerous epidemiological studies have explored relationships between background levels of chemicals in breast milk and health outcomes in infants and children.

OBJECTIVES

In this paper, we examine epidemiological literature to address the following question: Are infant exposures to background levels of environmental chemicals in breast milk and formula associated with adverse health effects? We critically review this literature a) to explore whether exposure-outcome associations are observed across studies, and b) to assess the literature quality.

METHODS

We reviewed literature identified from electronic literature searches. We explored whether exposure-outcome associations are observed across studies by assessing the quality (using a modified version of a previously published quality assessment tool), consistency, and strengths and weaknesses in the literature. The epidemiological literature included cohorts from several countries and examined infants/children either once or multiple times over weeks to years. Health outcomes included four broad categories: growth and maturation, morbidity, biomarkers, and neurodevelopment.

RESULTS

The available literature does not provide conclusive evidence of consistent or clinically relevant health consequences to infants exposed to environmental chemicals in breast milk at background levels.

CONCLUSIONS

It is clear that more research would better inform our understanding of the potential for health impacts from infant dietary exposures to environmental chemicals. A critical data gap is a lack of research on environmental chemicals in formula and infant/child health outcomes. https://doi.org/10.1289/EHP1954.

Perinatal exposure to chlordecone and infant growth

BACKGROUND

The intensive use of chlordecone (an organochlorine insecticide) in the French West Indies until 1993 resulted in a long-term soil and water contamination. Chlordecone has known hormonal properties and exposure through contaminated food during critical periods of development (gestation and early infancy) may affect growth.

OBJECTIVES

We aimed to assess the impact of prenatal and postnatal exposure to chlordecone on the growth of children from the TIMOUN mother-child cohort.

METHODS

Chlordecone was determined in cord plasma at birth (N=222) and in breast milk samples (at 3 months). Dietary chlordecone intake was estimated at 7 and 18 months, with food-frequency questionnaires and food-specific contamination data. Anthropometric measurements were taken at the 3-, 7- and 18-month visits and measurements reported in the infants' health records were noted. Structured Jenss-Bayley growth models were fitted to individual height and weight growth trajectories. The impact of exposure on growth curve parameters was estimated directly with adjusted mixed non-linear models. Weight, height and body mass index (BMI), and instantaneous height and weight growth velocities at specific ages were also analyzed relative to exposure.

RESULTS

Chlordecone in cord blood was associated with a higher BMI in boys at 3 months, due to greater weight and lower height, and in girls at 8 and 18 months, mostly due to lower height. Postnatal exposure was associated with lower height, weight and BMI at 3, 8 and 18 months, particularly in girls.

CONCLUSION

Chlordecone exposure may affect growth trajectories in children aged 0 to 18 months.

A comparison of presynaptic and postsynaptic dopaminergic agonists on inhibitory control performance in rats perinatally exposed to PCBs

Polychlorinated Biphenyls (PCBs) are very stable environmental contaminants whose exposure induces a number of health and cognitive concerns. Currently, it is well known that PCB exposure leads to poor performance on inhibitory control tasks. It is also well known that dopamine (DA) depletion within medial prefrontal cortex (mPFC) leads to poor performance on inhibitory control tasks. However, what is not well established is whether or not the inhibitory control problems found following PCB exposure are mediated by DA depletion in mPFC. This study was an investigation into the link between perinatal exposure to PCBs, the effect of this exposure on DA neurotransmission in the mPFC, and inhibitory-control problems during adulthood using a rodent model. The current study served to determine if microinjections of different DA agonists (the presynaptic DA transporter inhibitor and vesicular monoamine transporter agonist bupropion, the postsynaptic DA receptor 2 (DAD2) agonist quinpirole, and the postsynaptic DA receptor 1 (DAD1) agonist SKF81297) directly into the mPFC would differentially improve performance on an inhibitory control task in rats perinatally exposed to an environmentally relevant PCB mixture. Findings suggest several significant sex-based differences on differential reinforcement of low rates (DRL) 15 performance as well as some evidence of differential effectiveness of the DA agonists based on PCB exposure group.

Growth in Inuit children exposed to polychlorinated biphenyls and lead during fetal development and childhood

BACKGROUND

Because of their geographical location and traditional lifestyle, Canadian Inuit children are highly exposed to polychlorinated biphenyls (PCBs) and lead (Pb), environmental contaminants that are thought to affect fetal and child growth. We examined the associations of these exposures with the fetal and postnatal growth of Inuit children.

METHODS

We conducted a prospective cohort study among Inuit from Nunavik (Arctic Québec). Mothers were recruited at their first prenatal visit; children (n=290) were evaluated at birth and at 8-14 years of age. Concentrations of PCB 153 and Pb were determined in umbilical cord and child blood. Weight, height and head circumference were measured at birth and during childhood.

RESULTS

Cord blood PCB 153 concentrations were not associated with anthropometric measurements at birth or school age, but child blood PCB 153 concentrations were associated with reduced weight, height and head circumference during childhood. There was no association between cord Pb levels and anthropometric outcomes at birth, but cord blood Pb was related to smaller height and shows a tendency of a smaller head circumference during childhood.

INTERPRETATION

Our results suggest that chronic exposure to PCBs during childhood is negatively associated with skeletal growth and weight, while prenatal Pb exposure is related to reduced growth during childhood. This study is the first to link prenatal Pb exposure to poorer growth in school-age children.

Prenatal exposure to persistent organochlorines and childhood obesity in the US collaborative perinatal project

BACKGROUND

In some previous studies, prenatal exposure to persistent organochlorines such as 1,1,-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p´-DDE), polychlorinated biphenyls (PCBs), and hexachlorobenzene (HCB) has been associated with higher body mass index (BMI) in children.

OBJECTIVE

Our goal was to evaluate the association of maternal serum levels of β-hexachlorocyclohexane (β-HCH), p,p´-DDE, dichlorodiphenyltrichloroethane (p,p´-DDT), dieldrin, heptachlor epoxide, HCB, trans-nonachlor, oxychlordane, and PCBs with offspring obesity during childhood.

METHODS

The analysis was based on a subsample of 1,915 children followed until 7 years of age as part of the U.S. Collaborative Perinatal Project (CPP). The CPP enrolled pregnant women in 1959-1965; exposure levels were measured in third-trimester maternal serum that was collected before these organochlorines were banned in the United States. Childhood overweight and obesity were defined using age- and sex-specific cut points for BMI as recommended by the International Obesity Task Force.

RESULTS

Adjusted results did not show clear evidence for an association between organochlorine exposure and obesity; however, a suggestive finding emerged for dieldrin. Compared with those in the lowest quintile (dieldrin, < 0.57 μg/L), odds of obesity were 3.6 (95% CI: 1.3, 10.5) for the fourth and 2.3 (95% CI: 0.8, 7.1) for the highest quintile. Overweight and BMI were unrelated to organochlorine exposure.

CONCLUSIONS

In this population with relatively high levels of exposure to organochlorines, no clear associations with obesity or BMI emerged.

Polychlorinated biphenyls (PCBs) in relation to secondary sex ratio--a systematic review of published studies

There is reasonably strong evidence linking reduced secondary sex ratio (proportion of males) and environmental exposures. Polychlorinated biphenyls (PCBs) are persistent contaminants of the environment and several studies have reported an association of PCBs with birth outcomes. A decrease in the male/female sex ratio at birth has been reported in some, but not all studies. The aim of this systematic review was to summarize and pool the research findings about the influence of PCBs on sex ratio. Several article databases and reference lists of identified articles were searched. Studies reporting the proportion of boys and girls born to individuals who were exposed to high PCB concentrations were included. The primary outcome measure was the proportion of males in groups exposed to high or low levels of PCBs. Studies with both direct and indirect surrogate PCB measurements were included. The search and selection resulted in 15 eligible studies on the association between the sex ratio and parental PCB exposures. Analyses of the high exposure groups showed that the sex ratio was not significantly altered from the historical reference range in 13 of the 15 articles. The majority of the exposure studies reported also internal comparisons between high and low PCB exposure levels. The pooled 95% confidence interval estimate for the difference in high and low maternal exposure with direct PCB measure was - 0.048 with 95% CI of (-0.121, 0.026). There was no strong or moderate indication that parental exposure to PCBs alters the sex ratio of the children.

High levels of DDT in breast milk: intake, risk, lactation duration, and involvement of gender

We investigated presence and levels of DDT in 163 breast milk samples from four South African villages where, in three of them, malaria is controlled with DDT-sprayed indoors. Mean ΣDDT levels in breast milk were 18, 11, and 9.5 mg/kg mf (milk fat) from the three DDT-sprayed villages, respectively, including the highest ΣDDT level ever reported for breast milk from South Africa (140 mg/kg mf). Understanding the causes for these differences would be informative for exposure reduction intervention. The Provisional Tolerable Daily Intake (PTDI) for DDT by infants, and the Maximum Residue Limit (MRL) were significantly exceeded. DDT had no effect on duration of lactation. There were indications (not significant) from DDT-sprayed villages that first-born female infants drink milk with more ΣDDT than first-born male infants, and vice versa for multipara male and female infants, suggesting gender involvement on levels of DDT in breast milk - requiring further investigation.

The effect of prenatal and postnatal exposure to polychlorinated biphenyls and child neurodevelopment at age twenty four months

We examined the association between prenatal and postnatal exposure to PCBs and development at age 24 months as measured by the Bayley Scales of Infant Development II. 44 (85%) of 52 children had information available. When prenatal and postnatal exposure were modeled together, we found no association between total PCB exposure and the mental development index (MDI) or the physical development index (PDI). In examining PCB 153, we found no association between PCB 153 and MDI, while higher levels of postnatal exposure was associated with a decrease in PDI after adjustment [β for highest tertile=-24.9; 95% CI (-44.3, -5.5)]. Higher levels of prenatal PCB 153 exposure were associated with a statistically significant increased odds of screening positive for a motor delay. In sum, when prenatal and postnatal exposures were considered together, breast milk exposure to PCB 153 appears to be associated with decrements in motor development; however, we cannot rule out that the finding was due to chance.