Linking exposure to polychlorinated biphenyls with fatty fish consumption and reduced fetal growth among Danish pregnant women: a cause for concern?

Seafood Toxicant Exposure During Pregnancy, Lactation, and Childhood and Child Outcomes: A Scoping Review

Determining dietary recommendations for seafood consumed during pregnancy, lactation, and childhood requires consideration of the known nutritional benefits and potential harm due to toxicant exposure as they relate to child outcomes. This study aimed to describe the scope of the evidence associated with seafood-related toxicant exposure and child outcomes and to identify toxicant-outcome pairs that may have sufficient evidence to conduct a systematic review. We included studies examining seafood toxicant exposure during pregnancy, lactation, and childhood, and child outcomes. In total, 81 studies were included: 69 studies on exposure during pregnancy and lactation and 14 on exposure during childhood. The number of studies varied by toxicant and exposure population (maternal; child): mercury (n = 49; 7), methylmercury (n = 13; 3), polychlorinated biphenyls (PCBs; n = 11; 1), selenium (n = 11; 1), lead (n = 9; 3), perfluoroalkyl and polyfluoroalkyl substances (n = 8; 2), dichlorodiphenyltrichloroethane (n = 5; 1), arsenic (n = 4; 4), cadmium (n = 4; 4), zinc (n = 3; 2), polybrominated diphenyl ethers (n = 3; 1), dioxin-like compounds (n = 3; 0), iron (n = 2; 1), and magnesium (n = 1; 1). No studies examined polybrominated biphenyls, polycyclic aromatic hydrocarbons, iodine, aldrin, dieldrin, chlordane, chlorpyrifos, or microplastic exposures. Outcomes also varied by exposure population (maternal;child): neurodevelopment (n = 35; 9), child exposure biomarkers (n = 22; 4), growth (n = 17; 1), other adverse events (n = 4; 0), cardiometabolic (n = 3; 2), chronic disease indicators (n = 2; 0), and immune-related (n = 1; 2). Twelve maternal toxicant-outcome pairs had ≥3 studies, including mercury, methylmercury, lead, PCBs, perfluoroalkyl and polyfluoroalkyl substances, and arsenic as exposures and neurodevelopment, child exposure biomarkers, growth, and cardiometabolic as outcomes. For child exposure, only mercury and neurodevelopment had ≥3 studies. In conclusion, this scoping review shows relevant evidence for 14 of the 22 toxicants. Only 12 maternal and 1 child toxicant-outcome pairs, the majority of which examined maternal (methyl)mercury exposure, had ≥3 studies, our cutoff for consideration for systematic review. This scoping review indicates a paucity of research examining seafood toxicants beyond mercury and exposure during childhood. Systematic reviews are required to evaluate the associations for each toxicant-outcome pairs. The protocol was registered at Open Science Framework (https://doi.org/10.17605/OSF.IO/FQZTA).

Associations Between Maternal Polychlorinated Biphenyls (PCBs) Exposure from Seafood Consumption during Pregnancy and Lactation and Child Growth: A Systematic Review and Meta-Analysis

Beyond its nutritional benefits, seafood is a source of toxicant exposure including polychlorinated biphenyls (PCB). The association of PCB exposure from seafood intake during pregnancy and/or lactation (PL) and child growth outcomes is uncertain. This systematic review investigated the evidence and quantified the association between PCB exposure during PL from seafood intake and child growth outcomes. Embase, PubMed, and CENTRAL databases were searched from their inception for peer-reviewed English articles. Records were screened independently by 2 researchers at title and abstract, and then full-text levels. Studies were included if they: 1) were conducted in a country with a high Human Development Index, 2) measured maternal PCB exposure directly, 3) assessed the relationship between PCB and seafood exposures or PCB or seafood associations with a child growth outcome, and 4) were randomized or nonrandomized interventions, cohort, or nested case-control studies. Pooled partial correlations (rp) were calculated using random-effects models for studies with sufficient data and narratively for the remaining studies. Cochrane ROBINS-E and GRADE tools were used to assess risk of bias and certainty of evidence, respectively. Child growth outcomes included birthweight, birth length, head and chest circumference at birth, and small for gestational age (SGA). Seven studies were included. PCB exposure during PL was weakly but significantly associated with lower birthweight [rp = -0.07; 95% confidence interval (CI): -0.12, -0.02; n = 5], but showed no association with birth length (rp = -0.04; 95% CI: -0.09, 0.02; n = 4) and head circumference (rp = -0.03, 95% CI: -0.09, 0.03; n = 3). Studies on SGA and chest circumference yielded inconclusive results. The certainty of the evidence was low or very low because of the risk of bias from confounding, missing data, and exposure misclassification. The evidence suggests minimal to no link between PCB exposure from seafood during PL on child growth outcomes but with low to very low certainty. This trial was registered at PROSPERO as CRD42023493302.

Fish consumption benefits and PFAS risks: Epidemiology and public health recommendations

Finfish and shellfish intake (collectively referred to as fish) has been associated with health benefits, although fish often have chemical contaminants that are separately associated with health risks. The presence of chemical contaminants, however, does not inherently pose a health risk and optimizing the benefits is desirable for individual and population health. Reference doses (RfDs) and other comparison values that estimate contaminant or pollutant safety thresholds typically do not account for the benefits of the foods that carry them (e.g., fish, eggs, fruit, vegetables). Rather, these numbers are typically applied uniformly for various media such as food, soil, and water. This paper summarizes principal epidemiology studies on per- and polyfluoroalkyl substances (PFAS)-associated noncancer health indicators used by the United States Environmental Protection Agency (EPA) to develop RfDs for PFAS and compares these with the same health outcomes associated with seafood intake. Moreover, it frames these findings in relation to varying human PFAS exposures, fish intake amount, and fish type when the information is available. Further, it presents brief overviews of both general population temporal PFAS exposure trends and PFAS fish contaminant data in the United States. Finally, it discusses approaches that risk assessors and policy makers can consider in developing their fish consumption recommendations in relation to PFAS. In brief, epidemiology studies show that the benefits of fish intake generally counter the risks of PFAS exposure based on four noncancer health endpoints that EPA identified as having the greatest strength of evidence for PFAS health effects.

Fish Consumption and DHA Supplementation during Pregnancy: Study of Gestational and Neonatal Outcomes

Several studies have explored the association between fish consumption during pregnancy and favorable neonatal outcomes, although some yield conflicting results. The American College of Obstetricians and Gynecologists recommends two to three servings of low-mercury fish per week for pregnant or breastfeeding women. However, fish can be a source of pollutants, like methylmercury, impacting neurological development. Conflicting studies on docosahexaenoic acid (DHA) supplementation exist in the literature, possibly due to varied supplement dosages. This survey, involving 501 women, investigated fish consumption and DHA supplement intake concerning gestational and neonatal outcomes. Notably, 92.1% of participants consumed fish weekly, with significant differences observed in gestational weight gain, birth weight, and length for those eating fish ≥3 times weekly compared to non-consumers. This study supports the recommendation for pregnant women to include fish in their diet while limiting exposure to environmental pollutants. Omega-3 fatty acid supplements are suggested to attain nutritional benefits without mercury risk.

Maternal serum dioxin-like activity and gestational age at birth and indices of foetal growth: The Aarhus birth cohort

Human exposure to lipophilic persistent organic pollutants (lipPOP) is ubiquitous and life-long, beginning during foetal development. Exposure to lipPOP elicits a number of species and tissue specific responses including dioxin-like activity which involve the activation of aryl hydrocarbon receptor (AhR). This study aims i) to describe the combined dioxin-like activity in serum from Danish pregnant women collected during 2011-2013; ii) to assess the association between maternal serum dioxin-like activity, gestational age at birth and foetal growth indices. The serum lipPOP fraction was extracted using Solid Phase Extraction and cleaned-up on Supelco multi-layer silica and florisil columns. The combined dioxin-like activity of the extract was determined using the AhR reporter gene bioassay, expressed as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxic equivalent (TEQ) [AhR-TEQ (pg/g lipid)]. The associations of AhR-TEQ and foetal growth indices (birth weight, birth length and head circumference) and gestational age were assessed by linear regression models. We detected AhR-TEQ in 93.9 % of maternal first trimester serum samples, with a median level of 185 pg/g lipid. Each ln-unit increase in AhR-TEQ was associated with an increase in birth weight of 36 g (95 % CI: 5; 68), birth length of 0.2 cm (95 % CI: 0.01; 0.3) and pregnancy duration of 1 day (95 % CI: 0; 1.5). In women who never smoked, higher AhR-TEQ values were associated with higher birth weight and longer duration of gestation, while in smokers the association was the opposite. Mediation analyses suggested that gestational age may mediate the association of AhR-TEQ with foetal growth indices. We conclude that AhR activating substances are present in the bloodstream of almost all pregnant women in Denmark and the AhR-TEQ level was around four times higher than previously reported. The AhR-TEQ was associated with slightly longer gestational duration and thereby higher birth weight and birth length.

The association between first-trimester omega-3 fatty acid supplementation and fetal growth trajectories

BACKGROUND

Prenatal omega-3 fatty acid supplementation, particularly docosahexaenoic acid and eicosapentaenoic acid, has been associated with greater birthweight in clinical trials; however, its effect on fetal growth throughout gestation is unknown.

OBJECTIVE

This study aimed to examine the association between first-trimester docosahexaenoic acid and eicosapentaenoic acid supplementation and growth trajectories of estimated fetal weight and specific fetal biometrics measured longitudinally from the second trimester of pregnancy to delivery.

STUDY DESIGN

In a multisite, prospective cohort of racially diverse, low-risk pregnant women, we used secondary data analysis to examine fetal growth trajectories in relation to self-reported (yes or no) first-trimester docosahexaenoic acid and eicosapentaenoic acid supplementation. Fetal ultrasonographic measurements, including abdominal circumference, biparietal diameter, femur length, head circumference, and humerus length, were measured at enrollment (8-13 weeks) and up to 5 follow-up visits. Estimated fetal weight and head circumference-to-abdominal circumference ratio (a measure of growth symmetry) were calculated. Fetal growth trajectories were modeled for each measure using a linear mixed model with cubic splines. If significant differences in fetal growth trajectories between groups were observed (global P<.05), weekly comparisons were performed to determine when in gestation these differences emerged. Analyses were adjusted for maternal sociodemographics, parity, infant sex, total energy consumption, and diet quality score. All analyses were repeated using dietary docosahexaenoic acid and eicosapentaenoic acid intake, dichotomized at the recommended cutoff for pregnant and lactating women (≥0.25 vs <0.25 g/d), among women who did not report supplement intake in the first trimester of pregnancy were repeated.

RESULTS

Among 1535 women, 143 (9%) reported docosahexaenoic acid and eicosapentaenoic acid supplementation in the first trimester of pregnancy. Overall, first-trimester docosahexaenoic acid and eicosapentaenoic acid supplementation was associated with statistically significant differences (P-value <.05) in fetal growth trajectories during pregnancy. Specifically, estimated fetal weight was larger among women with docosahexaenoic acid and eicosapentaenoic acid supplementation than among those without supplementation (global P=.028) with significant weekly differences in median estimated fetal weight most apparent between 38 to 41 weeks of gestation (median estimated fetal weight difference at 40 weeks of gestation, 114 g). Differences in fetal growth trajectories for abdominal circumference (P=.003), head circumference (P=.003), and head circumference-to-abdominal circumference ratio (P=.0004) were also identified by supplementation status. In weekly comparisons, docosahexaenoic acid and eicosapentaenoic acid supplement use was associated with larger median abdominal circumference (changed from 2 to 9 mm) in midpregnancy onward (19 to 41 weeks), larger median head circumference between 30 to 33 weeks of gestation, and smaller median head circumference-to-abdominal circumference ratio in the second and third trimesters of pregnancy. There was no specific weekly difference in fetal femur length or humerus length by docosahexaenoic acid and eicosapentaenoic acid supplementation. First-trimester dietary sources of docosahexaenoic acid and eicosapentaenoic acid among women with no first-trimester docosahexaenoic acid and eicosapentaenoic acid supplementation (n=1392) were associated with differences in fetal biparietal diameter (P=.043), but not other metrics of fetal growth. At the recommended dietary docosahexaenoic acid and eicosapentaenoic acid levels compared with below-recommended levels, biparietal diameter was larger between 38 to 41 weeks of gestation.

CONCLUSION

In this racially diverse pregnancy cohort, first-trimester docosahexaenoic acid and eicosapentaenoic acid supplementation was associated with significant increases in fetal growth, specifically greater estimated fetal abdominal circumference in the second and third trimesters of pregnancy.

Fish intake and risk of melanoma in the NIH-AARP diet and health study

PURPOSE

Prior epidemiological studies evaluating the association between fish intake and melanoma risk have been few and inconsistent. Few studies distinguished different types of fish intake with risk of melanoma.

METHODS

We examined the associations between intake of total fish and specific types of fish and risk of melanoma among 491,367 participants in the NIH-AARP Diet and Health Study. We used multivariable-adjusted Cox proportional hazards regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

During 6,611,941 person-years of follow-up with a median of 15.5 years, 5,034 cases of malignant melanoma and 3,284 cases of melanoma in situ were identified. There was a positive association between higher total fish intake and risk of malignant melanoma (HR = 1.22, 95% CI = 1.11-1.34 for top vs. bottom quintiles, ptrend = 0.001) and melanoma in situ (HR = 1.28, CI = 1.13-1.44 for top vs. bottom quintiles, ptrend = 0.002). The positive associations were consistent across several demographic and lifestyle factors. There were also positive associations between tuna intake and non-fried fish intake, and risk of malignant melanoma and melanoma in situ. However, fried fish intake was inversely associated with risk of malignant melanoma, but not melanoma in situ.

CONCLUSIONS

We found that higher total fish intake, tuna intake, and non-fried fish intake were positively associated with risk of both malignant melanoma and melanoma in situ. Future studies are needed to investigate the potential biological mechanisms underlying these associations.

Dioxin-like Activity in Pregnant Women and Indices of Fetal Growth: The ACCEPT Birth Cohort

Exposure to lipophilic persistent organic pollutants (lipPOPs) elicits a number of species- and tissue-specific toxic responses, many of which involve the aryl hydrocarbon receptor (AhR). This study aims to measure the combined serum dioxin-like activity of lipPOPs in Greenlandic Inuit pregnant women and the associations with fetal growth indices. The combined dioxin-like activity of serum lipPOPs extracts was determined using the AhR reporter gene bioassay and expressed as pico-gram (pg) TCDD equivalent (TEQ) per gram serum lipid [AhR-TEQ (pg/g lipid)]. Significant AhR-TEQ was found in >87% of serum samples with the median level of 86.2 pg TEQ/g lipid. The AhR-TEQ level positively correlated with the marine food intake biomarker n-3/n-6 polyunsaturated fatty acids ratio, while negatively correlated with body mass index and parity. Women giving birth to infants with low birth weight (<2500 g) and length (<50 cm) had higher AhR-TEQ level compared to those with normal weight and length infants. For previous smokers, we found significant inverse associations between maternal AhR-TEQ level and fetal growth indices. In conclusion, exposure of Greenlandic Inuit pregnant women to dioxin-like compounds through traditional marine food can adversely influence the fetal growth via induced AhR activity. Smoking might have modifying effects.

Determination of organic pollutants in meconium and its relationship with fetal growth. Case control study in Northwestern Spain

OBJECTIVES

Antenatal exposure to organic pollutants is a leading public health problem. Meconium is a unique matrix to perform prenatal studies because it enables us to retrospectively evaluate fetal exposure accumulated during the second and third trimester. The aim of the present study was to evaluate associations between organic pollutant levels in meconium and birth weight in NW Spain.

METHODS

In this study, we quantify the concentrations of 50 organic pollutants together with the total values of the most important chemical groups in meconium using gas chromatography coupled to tandem mass spectrometry.

RESULTS

Organochlorine pesticides, polychlorinated biphenyls and polybrominated diphenyl ethers were detected with the highest levels in meconium from small for gestational age newborns. It was estimated that several congeners were statistically significant (p<0.05). However, organophosphorus pesticides attained higher concentrations in newborns with an appropriate weight.

CONCLUSIONS

The occurrence of transplacental transfer can be confirmed. Prenatal exposure to organic pollutants was associated with a decrease in birth weight and, therefore, organic pollutants could have an impact on fetal growth. Nevertheless, these results need validation in larger sample sized studies.

Identification of Arctic Food Fish Species for Anthropogenic Contaminant Testing Using Geography and Genetics

The identification of food fish bearing anthropogenic contaminants is one of many priorities for Indigenous peoples living in the Arctic. Mercury (Hg), arsenic (As), and persistent organic pollutants including polychlorinated biphenyls (PCBs) are of concern, and these are reported, in some cases for the first time, for fish sampled in and around King William Island, located in Nunavut, Canada. More than 500 salmonids, comprising Arctic char, lake trout, lake whitefish, and ciscoes, were assayed for contaminants. The studied species are anadromous, migrating to the ocean to feed in the summers and returning to freshwater before sea ice formation in the autumn. Assessments of muscle Hg levels in salmonids from fishing sites on King William Island showed generally higher levels than from mainland sites, with mean concentrations generally below guidelines, except for lake trout. In contrast, mainland fish showed higher means for As, including non-toxic arsenobetaine, than island fish. Lake trout were highest in As and PCB levels, with salmonid PCB congener analysis showing signatures consistent with the legacy of cold-war distant early warning stations. After DNA-profiling, only 4–32 Arctic char single nucleotide polymorphisms were needed for successful population assignment. These results support our objective to demonstrate that genomic tools could facilitate efficient and cost-effective cluster assignment for contaminant analysis during ocean residency. We further suggest that routine pollutant testing during the current period of dramatic climate change would be helpful to safeguard the wellbeing of Inuit who depend on these fish as a staple input to their diet. Moreover, this strategy should be applicable elsewhere.

Neonatal Weight and Prenatal Exposure to Polychlorinated Biphenyls: A Meta-Analysis

Background:

This research studied the relationship between maternal exposure to polychlorinated biphenyls and neonatal birth weight through systematic review and meta-analysis of existing literature.

Methods:

We searched for all the studies published in MEDLINE / PUBMEDN / EMBASE (Medical Abstract Database) by June 2018, and seven studies had been selected.

Results:

The results showed that there was significant correlation between birth weight reduction and PCBS exposure throughout pregnancy (β=-0.586g, 95%CI:-0.629,-0.543). There was a negative correlation between birth weight and PCBs exposure and umbilical cord serum (β=-0.833g) and maternal serum (β= -0.504g).Subgroup analyses showed significantly different effects of PCBs exposure on birth weight in different regions, stages of pregnancy and study designs. It was thought the heterogeneity was mainly caused by geographical regions, stages of pregnancy, and the assessment methods.

Conclusion:

The meta analysis revealed a negative correlation between PCBs exposure and birth weight but there was significant difference in the correlation between birth weight loss.

Exposure to Persistent Organic Pollutants and Birth Characteristics: The Upstate KIDS Study

BACKGROUND

Prenatal exposure to persistent organic pollutants (POPs) may be associated with obesogenic effects in offspring. Our study is the first to investigate associations between concentrations of POPs from newborn dried blood spots (DBS) and birth characteristics.

METHODS

Concentrations of 10 polychlorinated biphenyl congeners (PCBs), polybrominated diphenyl ether-47 (PBDE-47), and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) were measured from DBSs collected at birth from 2,065 singleton infants. DBS samples were pooled in groups of five and assayed together to reach limits of detection. Differences in risk of large for gestational age (LGA, defined as >90th percentile of birth weight for sex and gestational age), small for gestational age (SGA, <10th), and preterm birth (gestational age <37 weeks) were estimated using logistic regression per unit (ng/ml) increase in concentration of each chemical, adjusting for individual-level covariates, including maternal age, race/ethnicity, prepregnancy BMI, education, parity, smoking, and infant sex while assuming a gamma distribution and using multiple imputation to account for pools.

RESULTS

There were 215 (11.3%) singletons born LGA, 158 (7.5%) born SGA, and 157 (7.6%) born preterm. Higher concentrations of POPs were positively associated with slightly higher risk of LGA and higher birth weight.

CONCLUSIONS

Relationships between POPs measured in newborn DBS and birth size were mixed. Pooled analysis methods using DBS could address challenges in limits of detection and costs for population-based research.

Fish and seafood consumption during pregnancy and the risk of asthma and allergic rhinitis in childhood: a pooled analysis of 18 European and US birth cohorts

Background

It has been suggested that prenatal exposure to n-3 long-chain fatty acids protects against asthma and other allergy-related diseases later in childhood. The extent to which fish intake in pregnancy protects against child asthma and rhinitis symptoms remains unclear. We aimed to assess whether fish and seafood consumption in pregnancy is associated with childhood wheeze, asthma and allergic rhinitis.

Methods

We pooled individual data from 60 774 mother-child pairs participating in 18 European and US birth cohort studies. Information on wheeze, asthma and allergic rhinitis prevalence was collected using validated questionnaires. The time periods of interest were: infancy (0-2 years), preschool age (3-4 years), and school age (5-8 years). We used multivariable generalized models to assess associations of fish and seafood (other than fish) consumption during pregnancy with child respiratory outcomes in cohort-specific analyses, with subsequent random-effects meta-analyses.

Results

The median fish consumption during pregnancy ranged from 0.44 times/week in The Netherlands to 4.46 times/week in Spain. Maternal fish intake during pregnancy was not associated with offspring wheeze symptoms in any age group nor with the risk of child asthma [adjusted meta-analysis relative risk (RR) per 1-time/week = 1.01, 95% confidence interval 0.97-1.05)] and allergic rhinitis at school age (RR = 1.01, 0.99-1.03). These results were consistently found in further analyses by type of fish and seafood consumption and in sensitivity analyses.

Conclusion

We found no evidence supporting a protective association of fish and seafood consumption during pregnancy with offspring symptoms of wheeze, asthma and allergic rhinitis from infancy to mid childhood.

Temporal trends of lipophilic persistent organic pollutants in serum from Danish nulliparous pregnant women 2011-2013

The use of the lipophilic persistent organic pollutants (POPs) including polychlorinated biphenyls (PCBs) and several organochlorine pesticides (OCPs) has been prohibited for more than 30 years. In this study, we present the temporal trends of the lipophilic POP serum concentrations in Danish nulliparous pregnant women between 2011 and 2013. We randomly selected 197 pregnant women (gestational age 11-13) from the Aarhus Birth Cohort. The concentrations of the lipophilic POPs in the serum samples were analyzed using gas chromatography. The concentrations were corrected for total serum lipids. The statistical analysis was performed by regression analysis with adjustment for age, BMI, gestational age at blood draw, and smoking status. The serum concentrations of PCB 118, 138, 153, 156, 170, 180, 187, and hexachlorobenzen, trans-nonachlor, β-hexachlorocyclohexane (β-HCH), and p,p'-dichlorodiphenyldichloroethylene were lower in 2013 than in 2011. However, the oxychlordane concentration was lowest in 2011. The serum levels of most lipophilic POPs followed downward trends during the study period, which was expected, as these compounds has been banned for many years. The upward trend of oxychlordane was unexpected and presumably a chance finding.

Effects of intrauterine exposures to polychlorinated biphenyls, methylmercury, and lead on birth weight in Japanese male and female newborns

BACKGROUND

The effects of prenatal exposures to polychlorinated biphenyls (PCBs), methylmercury, and lead on birth weight remain disputable. The aim of this study was to investigate whether these chemicals affect birth weight of Japanese newborns, with special emphasis on determining whether these effects differ between males and females.

METHODS

The subjects from Tohoku Study of Child Development, which was designed to examine the developmental effects of prenatal exposures to such hazardous chemicals, were 489 mother-newborn pairs with complete data including smoking habit during pregnancy.

RESULTS

The mean birth weight of all newborns was 3083 (range, 2412-4240) g. The median values of biomarkers in cord blood were 46.0 (5th and 95th percentiles, 18.6-113.8) ng/g-lipid for total PCBs, 10.1 (4.3-22.4) ng/g for total mercury (THg), and 1.0 (0.6-1.7) μg/dL for lead. The birth weight was significantly heavier in the 252 male newborns than in the 237 female ones. A negative association between total PCBs and birth weight was observed in both male and female newborns, even after adjusting for possible confounders. However, a negative association of THg with birth weight was found only in the male newborns. There was no significant relationship between lead and birth weight in both groups.

CONCLUSION

Birth weight appears to be affected by prenatal PCB exposure in Japanese male and female newborns, and the effect of methylmercury exposure on male fetal growth may be stronger than that for females. This implication is that the effects on fetal growth should be assessed in males and females separately.

Effects of intrauterine exposures to polychlorinated biphenyls, methylmercury, and lead on birth weight in Japanese male and female newborns

BACKGROUND

The effects of prenatal exposures to polychlorinated biphenyls (PCBs), methylmercury, and lead on birth weight remain disputable. The aim of this study was to investigate whether these chemicals affect birth weight of Japanese newborns, with special emphasis on determining whether these effects differ between males and females.

METHODS

The subjects from Tohoku Study of Child Development, which was designed to examine the developmental effects of prenatal exposures to such hazardous chemicals, were 489 mother-newborn pairs with complete data including smoking habit during pregnancy.

RESULTS

The mean birth weight of all newborns was 3083 (range, 2412-4240) g. The median values of biomarkers in cord blood were 46.0 (5th and 95th percentiles, 18.6-113.8) ng/g-lipid for total PCBs, 10.1 (4.3-22.4) ng/g for total mercury (THg), and 1.0 (0.6-1.7) μg/dL for lead. The birth weight was significantly heavier in the 252 male newborns than in the 237 female ones. A negative association between total PCBs and birth weight was observed in both male and female newborns, even after adjusting for possible confounders. However, a negative association of THg with birth weight was found only in the male newborns. There was no significant relationship between lead and birth weight in both groups.

CONCLUSION

Birth weight appears to be affected by prenatal PCB exposure in Japanese male and female newborns, and the effect of methylmercury exposure on male fetal growth may be stronger than that for females. This implication is that the effects on fetal growth should be assessed in males and females separately.

Prenatal exposure to persistent organic pollutants and offspring allergic sensitization and lung function at 20 years of age

BACKGROUND

Prenatal exposures to persistent organic pollutants (POPs) have been associated with asthma medication use and self-reported symptoms, but associations with lung function and allergic sensitization have been minimally explored. The aim of the study was to examine the associations between prenatal exposures to POPs and allergic sensitization and lung function in 20-year-old offspring.

METHODS

In a Danish cohort of 965 pregnant women established in 1988-1989, six polychlorinated biphenyl (PCB) congeners, hexachlorobenzene (HCB), and dichlorodiphenyldichloroethylene (p,p'-DDE) were quantified in archived maternal serum drawn in gestational week 30 (n = 872). Among those with available maternal exposure information, at age 20, 421 offspring attended attended a clinical examination including measurements of allergic sensitization (serum-specific IgE ≥ 0.35 kUA /L) (n = 418) and lung function [forced expiratory volume in one second (FEV1 ) and forced vital capacity (FVC)] (n = 414).

RESULTS

There were no associations between maternal concentrations of POPs and offspring allergic sensitization at 20 years of age. Maternal concentrations of POPs were, however, positively associated with offspring airway obstruction (FEV1 /FVC < 75%). Compared to offspring in the first tertile of exposure, offspring in the third tertile of dioxin-like PCB exposure had an OR of 2.96 (95% CI: 1.14-7.70). Similar associations for non-dioxin-like PCBs, HCB, and p,p'-DDE were 2.68 (1.06-6.81), 2.63 (1.07, 6.46), and 2.87 (1.09, 7.57), respectively. No associations were observed with reduced lung function (FEV1 % of predicted value < 90%).

CONCLUSION AND CLINICAL RELEVANCE

Our data indicate that prenatal exposure to POPs appears to be associated with airway obstruction but not allergic sensitization at 20 years of age. The findings support that chronic obstructive lung diseases may have at least part of their origins in early life.

Prenatal methylmercury exposure and language delay at three years of age in the Norwegian Mother and Child Cohort Study

Prenatal methylmercury (MeHg) exposure and its possible neurodevelopmental effects in susceptible children are of concern. Studies of MeHg exposure and negative health outcomes have shown conflicting results and it has been suggested that co-exposure to other contaminants and/or nutrients in fish may confound the effect of MeHg. Our objective was to examine the association between prenatal exposure to MeHg and language and communication development at three years, adjusting for intake of fish, n-3 long chain polyunsaturated fatty acids (n-3 LCPUFAs) and co-exposure to dioxins and dioxin like polychlorinated biphenyls (dl-PCBs). We used data from the Norwegian Mother and Child Cohort Study (MoBa) collected between 2002 and 2008. The study sample consisted of 46,750 mother-child pairs. MeHg exposure was calculated from reported fish intake during pregnancy by a FFQ in mid-pregnancy. Children's language and communication skills were measured by maternal report on the Dale and Bishop grammar rating and the Ages and Stages communication scale (ASQ). We estimated odds ratios (OR) and 95% confidence intervals (CI) using logistic regressions. Median MeHg exposure was 1.3μg/day, corresponding to 0.14μg/kgbw/week. An exposure level above the 90th percentile (>2.6μg/day, >0.29μg/kgbw/week) was defined as the high MeHg exposure. Results indicated an association between high MeHg exposure and unintelligible speech with an adjusted OR 2.22 (1.31, 3.72). High MeHg exposure was also associated with weaker communication skills adjusted OR 1.33 (1.03, 1.70). Additional adjustment for fish intake strengthened the associations, while adjusting for PCBs and n-3 LCPUFA from diet or from supplements had minor impact. In conclusion, significant associations were found between prenatal MeHg exposure above the 90th percentile and delayed language and communication skills in a generally low exposed population.

Determinants of plasma PCB, brominated flame retardants, and organochlorine pesticides in pregnant women and 3 year old children in The Norwegian Mother and Child Cohort Study

BACKGROUND

Exposure to persistent organic pollutants (POPs) during prenatal and postnatal life has been extensively studied in relation to adverse health effects in children.

OBJECTIVES

The aim was to identify determinants of the concentrations of polychlorinated biphenyls (PCBs), brominated flame retardants (polybrominated diphenyl ethers, PBDEs; polybrominated biphenyl, PBB), and organochlorine pesticides (OCPs) in blood samples from pregnant women and children in The Norwegian Mother and Child Cohort Study (MoBa).

METHODS

Blood samples were collected from two independent subsamples within MoBa; a group of women (n=96) enrolled in mid-pregnancy during the years 2002-2008 and a group of 3 year old children (n=99) participating during 2010-2011. PCB congeners (74, 99, 138, 153, 180, 170, 194, 209, 105, 114, 118, 156, 157, 167, and 189), brominated flame retardants (PBDE-28, 47, 99, 100, 153, 154, and PBB-153), as well as the OCPs hexachlorobenzene (HCB), oxychlordane, 4,4'dichlorodiphenyltrichloroethane (DDT), and 4,4'dichlorodiphenyldichloroethylene (DDE) were measured in both pregnant women and children.

RESULTS

Age, low parity, and low pre-pregnant BMI were the most important determinants of increased plasma concentrations of POPs in pregnant women. In 3 year old children, prolonged breastfeeding duration was a major determinant of increased POP concentrations. Estimated dietary exposure to PCBs during pregnancy was positively associated with plasma concentrations in 3 year old children, but not in pregnant women. Plasma concentrations were approximately 40% higher in children compared to pregnant women.

CONCLUSIONS

Several factors associated with exposure and toxicokinetics, i.e. accumulation, excretion and transfer via breastmilk of POPs were the main predictors of POP levels in pregnant women and children. Diet, which is the main exposure source for these compounds in the general population, was found to predict PCB levels only among children. For the PBDEs, for which non-dietary sources are more important, toxicokinetic factors appeared to have less predictive impact.

Does eating oily fish improve gestational and neonatal outcomes? Findings from a Sicilian study

BACKGROUND

Fish is a source of long-chain polyunsaturated n-3 fatty acids, but it may also contain a number of pollutants.

METHODS

Between April and July 2013, we selected 114 women who gave birth to living babies, and divided them according to type and frequency of the fish consumed. We evaluated both gestational and neonatal outcomes. Docosahexaenoic acid (DHA) supplementation was taken into account.

FINDINGS

One hundred and four women (91.2%) consumed fish on the average of 4.7 times/month, while 10 (8.8%) did not consume fish at all. Fifty-nine women (51.8%) were taking supplements containing DHA (200mg/day), almost all of whom (n=55) consumed fish. Pregnancy induced hypertension was more frequent in non-fish eaters than in fish eaters (20% vs 4.8%, P=0.056). Consumption of small size oily fish correlated positively with both neonatal weight (r=0.195, P=0.037) and head circumference (r=0.211, P=0.024). In contrast, consumption of lean fish or shellfish correlated negatively with neonatal head circumference (r=0.206, P=0.028, or r=0.192, P=0.041).

DISCUSSION

These data agree with previous observational studies and reinforce the protective role of small oily fish consumption on preterm birth risk, neonatal weight, length and head circumference.

CONCLUSION

Small oily fish consumption should be favored over other types of fish.

Effects of in utero exposure to polychlorinated biphenyls, methylmercury, and polyunsaturated fatty acids on birth size

The adverse effects of in utero exposure to polychlorinated biphenyls (PCBs) or methylmercury (MeHg), and the beneficial effects of nutrients from maternal fish intake might have opposing influences on fetal growth. In this study, we assessed the effects of in utero exposure to PCBs and MeHg on birth size in the Japanese population, which is known to have a high frequency of fish consumption. The concentrations of PCBs and polyunsaturated fatty acids in maternal blood, and the total mercury in hair (as a biomarker of MeHg exposure) were measured during pregnancy and at delivery. Maternal intakes of fish (subtypes: fatty and lean) and shellfishes were calculated from a food frequency questionnaire administered at delivery. Newborn anthropometric measurement data were obtained from birth records. The associations between chemical exposures and birth size were analyzed by using multiple regression analysis with adjustment for confounding factors among 367 mother-newborn pairs. The birth weight was 3073±37 g (mean±SD). The incidence of babies small for gestational age (SGA) by weight was 4.9%. The median concentrations of total PCBs and hair mercury were 108 ng/g lipid and 1.41 μg/g, respectively. There was no overall association between mercury concentrations and birth weight, birth length, chest circumference, and head circumference. We observed that the risk of SGA by weight decreased with increasing mercury concentration in regression analyses with adjustment for polyunsaturated fatty acids. Our results suggest that the beneficial effect of essential nutrition may mask the adverse effects of MeHg on birth size. The concentrations of PCBs had no association with birth size.

Association of PCBs and allergies in children

Recently, the incidence rates of childhood allergies have been rising around the world. The presence of persistent chemical pollutants in the environment and exposure to air pollutants are often cited as potential causes of childhood allergies. Accordingly, epidemiological studies of the associations between exposure to low levels of pollutants and adverse health effects are essential. However, at present no useful biomarkers for evaluating such associations have been developed. Thus, using a molecular epidemiological approach we planned to identify candidate biomarkers of pollutant-induced adverse health effects that can be used in children. In asthmatic children, we found that the serum levels of several polychlorinated biphenyl (PCB) congener sub-types were significantly positively correlated with interleukin (IL)-8 mRNA expression, whereas in a sub-group of children who displayed positive immunoglobulin E (IgE) responses to milk or egg proteins IL-22 mRNA expression was demonstrated to be useful for detecting the adverse health effects of environmental pollutants, particularly PCB congeners. In conclusion, the mRNA expression levels of IL-8 and IL-22 can be used to detect children who are at particular risk of adverse health events caused by environmental pollutants, especially PCBs.

Study on polychlorobiphenyl serum levels in French consumers of freshwater fish

INTRODUCTION

Polychlorobiphenyls (PCBs) are persistent pollutants that are widespread in the environment and in foodstuffs, particularly in freshwater fish, which frequently exceed the maximum levels set by European regulations.

OBJECTIVES

First, we describe the consumption of freshwater fish and serum PCB levels in French anglers, a population expected to have the highest level of dietary PCB exposure. Second, we investigated whether there is a statistical relationship between serum PCB levels and the angler consumption of freshwater fish with high PCB bioaccumulation potential (PCB-BP(+) freshwater fish) in order to make recommendations with regard to safe consumption of freshwater fish.

METHODS

We conducted a survey of anglers from six sites with contrasting PCB contamination levels. The survey included a food consumption frequency questionnaire and blood samples were taken to assess serum PCB levels. We used a regression model to determine the main factors contributing to serum PCB levels.

RESULTS

Consumption of PCB-BP(+) freshwater fish was relatively infrequent. Serum PCB levels of the study population and of women of childbearing age were in the same range as those observed in the French population and in neighbouring European countries, but higher than in the North American population. The two factors with the highest positive association with serum PCB levels were age (R(2)=61%) and the consumption of PCB-BP(+) freshwater fish (R(2)=2%). Using the regression model, we calculated, for several scenarios depending on the age and gender of the population, the maximum annual frequencies for PCB-BP(+) freshwater fish consumption that do not exceed the critical body burden threshold.

CONCLUSION

Following the results of this study, the French agency for food, environmental and occupational health and safety (ANSES) issued an opinion and recommended some specific maximum freshwater fish consumption frequencies to protect the French general population.

Useful biomarkers for assessing the adverse health effects of PCBs in allergic children: pediatric molecular epidemiology

The incidences of childhood allergies have been increasing in recent years in many parts of the world. The development of allergic disorders is attributed to a complex series of interactions between individuals' genetic backgrounds and their immune and psychoneurotic responses to environmental factors. Among the various possible environmental causes of childhood allergies, the early exposure of developing infants to air pollutants and the presence of persistent chemical pollutants such as pesticides have been suggested most frequently. Therefore, it is very important to obtain epidemiological evidence of direct associations between clearly defined adverse health effects and exposure to low levels of pollutants. However, there are no useful biomarkers for assessing such associations. Thus, we planned to establish reliable health-related biomarkers that could be used to investigate these relationships in children. The serum concentrations of several sub-types of polychlorinated biphenyl (PCB) congeners were found to be significantly correlated with interleukin (IL)-8 mRNA expression among asthmatic children. In addition, IL-22 mRNA expression was found to be particularly useful for detecting the effects of environmental pollutants, especially PCB congeners, in a sub-population of vulnerable children who exhibited positive immunoglobulin E (IgE) responses to milk or egg. Furthermore, we detected significant differences in IL-22 mRNA expression between the IgE-negative non-asthmatic subjects and the asthmatic children who exhibited positive IgE reactions toward egg or milk. In conclusion, IL-8 and IL-22 mRNA expressions could be useful biomarkers for detecting sub-populations of children who are particularly vulnerable to the adverse health effects of environmental pollutants, especially PCBs.

The Northern Norway Mother-and-Child Contaminant Cohort (MISA) Study: PCA analyses of environmental contaminants in maternal sera and dietary intake in early pregnancy

BACKGROUND

Although predictors of contaminants in serum or whole blood are usually examined by chemical groups (e.g., POPs, toxic and/or essential elements; dietary sources), principal component analysis (PCA) permits consideration of both individual substances and combined variables.

OBJECTIVES

Our study had two primary objectives: (i) Characterize the sources and predictors of a suite of eight PCBs, four organochlorine (OC) pesticides, five essential and five toxic elements in serum and/or whole blood of pregnant women recruited as part of the Mother-and-Child Contaminant Cohort Study conducted in Northern Norway (The MISA study); and (ii) determine the influence of personal and social characteristics on both dietary and contaminant factors.

METHODS

Recruitment and sampling started in May 2007 and continued for the next 31 months until December 2009. Blood/serum samples were collected during the 2nd trimester (mean: 18.2 weeks, range 9.0-36.0). A validated questionnaire was administered to obtain personal information. The samples were analysed by established laboratories employing verified methods and reference standards. PCA involved Varimax rotation, and significant predictors (p≤0.05) in linear regression models were included in the multivariable linear regression analysis.

RESULTS

When considering all the contaminants, three prominent PCA axes stood out with prominent loadings of: all POPs; arsenic, selenium and mercury; and cadmium and lead. Respectively, in the multivariate models the following were predictors: maternal age, parity and consumption of freshwater fish and land-based wild animals; marine fish; cigarette smoking, dietary PCA axes reflecting consumption of grains and cereals, and food items involving hunting. PCA of only the POPs separated them into two axes that, in terms of recently published findings, could be understood to reflect longitudinal trends and their relative contributions to summed POPs.

CONCLUSIONS

The linear combinations of variables generated by PCA identified prominent dietary sources of OC groups and of prominent toxic elements and highlighted the importance of maternal characteristics.

Maternal diet, prenatal exposure to dioxin-like compounds and birth outcomes in a European prospective mother-child study (NewGeneris)

Maternal diet can result in exposure to environmental contaminants including dioxins which may influence foetal growth. We investigated the association between maternal diet and birth outcomes by defining a dioxin-rich diet. We used validated food frequency questionnaires to assess the diet of pregnant women from Greece, Spain, United Kingdom, Denmark and Norway and estimated plasma dioxin-like activity by the Dioxin-Responsive Chemically Activated LUciferase eXpression (DR-CALUX®) bioassay in 604 maternal blood samples collected at delivery. We applied reduced rank regression to identify a dioxin-rich dietary pattern based on dioxin-like activity (DR-CALUX®) levels in maternal plasma, and calculated a dioxin-diet score as an estimate of adherence to this dietary pattern. In the five country population, dioxin-diet score was characterised by high consumption of red and white meat, lean and fatty fish, low-fat dairy and low consumption of salty snacks and high-fat cheese, during pregnancy. The upper tertile of the dioxin-diet score was associated with a change in birth weight of -121g (95% confidence intervals: -232, -10g) compared to the lower tertile after adjustment for confounders. A small non-significant reduction in gestational age was also observed (-1.4days, 95% CI: -3.8, 1.0days). Our results suggest that maternal diet might contribute to the exposure of the foetus to dioxins and dioxin-like compounds and may be related to reduced birth weight. More studies are needed to develop updated dietary guidelines for women of reproductive age, aiming to the reduction of dietary exposure to persistent organic pollutants as dioxins and dioxin-like compounds.

Fish intake during pregnancy, fetal growth, and gestational length in 19 European birth cohort studies

BACKGROUND

Fish is a rich source of essential nutrients for fetal development, but in contrast, it is also a well-known route of exposure to environmental pollutants.

OBJECTIVE

We assessed whether fish intake during pregnancy is associated with fetal growth and the length of gestation in a panel of European birth cohort studies.

DESIGN

The study sample of 151,880 mother-child pairs was derived from 19 population-based European birth cohort studies. Individual data from cohorts were pooled and harmonized. Adjusted cohort-specific effect estimates were combined by using a random- and fixed-effects meta-analysis.

RESULTS

Women who ate fish >1 time/wk during pregnancy had lower risk of preterm birth than did women who rarely ate fish (≤ 1 time/wk); the adjusted RR of fish intake >1 but <3 times/wk was 0.87 (95% CI: 0.82, 0.92), and for intake ≥ 3 times/wk, the adjusted RR was 0.89 (95% CI: 0.84, 0.96). Women with a higher intake of fish during pregnancy gave birth to neonates with a higher birth weight by 8.9 g (95% CI: 3.3, 14.6 g) for >1 but <3 times/wk and 15.2 g (95% CI: 8.9, 21.5 g) for ≥ 3 times/wk independent of gestational age. The association was greater in smokers and in overweight or obese women. Findings were consistent across cohorts.

CONCLUSION

This large, international study indicates that moderate fish intake during pregnancy is associated with lower risk of preterm birth and a small but significant increase in birth weight.

Maternal concentrations of persistent organochlorine pollutants and the risk of asthma in offspring: results from a prospective cohort with 20 years of follow-up

BACKGROUND

Previous findings suggest that developmental exposures to persistent organochlorine pollutants (POPs) may be detrimental for the development of the immune system in the offspring. Whether these suspected immunoregulatory effects persist beyond early childhood remains unclear.

OBJECTIVES

The objective of this study was to evaluate the association between maternal serum concentrations of POPs and the risk of asthma in offspring after 20 years of follow-up.

METHODS

A birth cohort with 965 women was formed in 1988-1989 in Aarhus, Denmark. Concentrations of six polychlorinated biphenyls (PCBs) (congeners 118, 138, 153, 156, 170, 180), hexachlorobenzene (HCB), and dichlorodiphenyldichloroethylene (p,p´-DDE) were quantified in maternal serum (n=872) collected in gestation week 30. Information about offspring use of asthma medications was obtained from the Danish Registry of Medicinal Product Statistics.

RESULTS

Maternal serum concentrations of HCB and dioxin-like PCB-118 were positively associated with offspring asthma medication use after 20 years of follow-up (p for trend<0.05). Compared with subjects in the first tertile of maternal concentration, those in the third tertile of PCB-118 had an adjusted hazard ratio (HR) of 1.90 (95% CI: 1.12, 3.23). For HCB the HR for the third versus the first tertile of maternal concentration was 1.92 (95% CI: 1.15, 3.21). Weak positive associations were also estimated for PCB-156 and the non-dioxin-like PCBs (PCBs 138, 153, 170, 180). No associations were found for p,p´-DDE.

CONCLUSIONS

Maternal concentrations of PCB-118 and HCB were associated with increased risk of asthma in offspring followed through 20 years of age.

Maternal dietary intake of dioxins and polychlorinated biphenyls and birth size in the Norwegian Mother and Child Cohort Study (MoBa)

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.

Maternal diet, prenatal exposure to dioxins and other persistent organic pollutants and anogenital distance in children

We investigated the potential endocrine disruptive effect of prenatal exposure to persistent organic pollutants (POPs) through maternal diet, by measuring anogenital distance in newborns and young children. We included 231 mothers and their newborns measured at birth from the Rhea study in Crete, Greece and the Hmar study in Barcelona, Spain and 476 mothers and their children measured between 1 and 2 years from the Rhea study. We used food frequency questionnaires to assess maternal diet and estimated plasma dioxin-like activity by the Dioxin-Responsive Chemically Activated LUciferase eXpression (DR-CALUX®) and other POPs in maternal samples. We defined a "high-fat diet" score, as a prenatal exposure estimate, that incorporated intakes of red meat, processed meat, fatty fish, seafood, eggs and high-fat dairy products during pregnancy. Increasing maternal "high-fat diet" score was related to increasing dioxin-like activity and serum concentrations of lipophilic persistent organic pollutants in maternal blood. An inverse dose-response association was found between "high-fat diet" score and anoscrotal distance in newborn males. The highest tertile of the maternal score was associated with -4.2 mm (95% CI -6.6 to -1.8) reduction in anoscrotal distance of newborn males, compared to the lowest tertile. A weak positive association was found between the "high-fat diet" score and anofourchetal distance in newborn females. In young children we found no association between maternal "high-fat diet" score and anogenital distances. In conclusion, maternal high-fat diet may be linked to high prenatal exposure to persistent organic pollutants and endocrine disruptive effects, resulting to phenotypic alterations of the reproductive system.

Prenatal exposure to polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) may influence birth weight among infants in a Swedish cohort with background exposure: a cross-sectional study

BACKGROUND

Prenatal exposure to persistent organic pollutants, e.g. polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) has been suggested to negatively affect birth weight although epidemiological evidence is still inconclusive. We investigated if prenatal exposure to PCBs and PBDEs is related to birth weight in a Swedish population with background exposure.

METHODS

Breast milk was sampled during the third week after delivery from first-time mothers in Uppsala county, Sweden 1996-2010 (POPUP cohort) (N = 413). Samples were analysed for di-ortho PCBs (CB-138, 153, 180) and tetra- to hexa- brominated PBDEs (BDE-47, 99, 100, 153). Simple and multiple linear regression models were used to investigate associations between lipid-adjusted, ln-transformed PCB and PBDE concentrations, and birth weight. Covariates included in the multivariate regression model were PCB and PBDE exposure, maternal age, pre-pregnancy BMI, weight gain during pregnancy, education, smoking, gender of the infant and gestational length. The effect of including fish consumption was also investigated.

RESULTS

In the multivariate model, prenatal exposure to di-ortho PCBs was significantly associated with increased birth weight (β = 137; p = 0.02). The result did not change when gestational length was added to the model. An inverse association between PBDE(4) (sum of BDE-47, -99, -100 and -153) and birth weight was observed in the multivariate model including gestational length (β = -106; p = 0.04). Maternal pre-pregnancy BMI and weight gain during pregnancy were important confounders of the association between di-ortho PCBs and birth weight. The associations were not alleviated after adjustment for fish consumption, a major source of PCB and PBDE exposure. The observed associations were stronger for boys than for girls.

CONCLUSIONS

Our results indicate that prenatal exposure to di-ortho PCBs and PBDE(4) may influence birth weight in different directions, i.e. PCB exposure was associated with higher birth weight and PBDE exposure with lower birth weight. Maternal pre-pregnancy BMI and weight gain during pregnancy were important confounders that may hide positive association between di-ortho PCB exposure and birth weight if they are not included in the statistical model. We speculate that even small PCB- and PBDE-induced shifts in the distribution of birth weight may influence future public health in populations with background exposure.

Sociodemographic characteristics and food habits of organic consumers – a study from the Danish National Birth Cohort

Objective

To develop a basis for building models that can examine the impact of organic food (OF) choices on maternal and offspring health, including identification of factors associated with OF consumption and underlying dietary patterns.

Design

Dietary intake was collected for the preceding month from an FFQ in mid-pregnancy and information on sociodemographic characteristics was collected from telephone interviews during pregnancy. From a question about OF consumption in the FFQ, including six food categories, an OF preference index was calculated. Latent variables that captured the variability in OF choices in relation to dietary intake were defined.

Setting

The Danish National Birth Cohort (DNBC), 1996–2002.

Subjects

Pregnant women from DNBC (n 60 773).

Results

We found that frequent OF use was highly associated with age, occupational status, urbanization, smoking and vegetarianism. By principal components analysis we identified two eating patterns, a ‘Western dietary pattern’ and a ‘Prudent dietary pattern’, that explained 14·2 % of the variability in data. Frequent OF users consumed a more ‘prudent’ diet compared with non-users and had significantly higher intakes of vegetables (+67 %), fibre (+13 %) and n-3 fatty acids (+11 %) and less saturated fat (−8 %).

Conclusions

Frequent OF users seemed to have a healthier lifestyle than non-users. These findings highlight a major challenge in observational studies examining the impact of OF consumption on health due to potentially irremediable confounding factors.

Birth weight and prenatal exposure to polychlorinated biphenyls (PCBs) and dichlorodiphenyldichloroethylene (DDE): a meta-analysis within 12 European Birth Cohorts

OBJECTIVES

Exposure to high concentrations of persistent organochlorines may cause fetal toxicity, but the evidence at low exposure levels is limited. Large studies with substantial exposure contrasts and appropriate exposure assessment are warranted. Within the framework of the EU (European Union) ENRIECO (ENvironmental Health RIsks in European Birth Cohorts) and EU OBELIX (OBesogenic Endocrine disrupting chemicals: LInking prenatal eXposure to the development of obesity later in life) projects, we examined the hypothesis that the combination of polychlorinated biphenyls (PCBs) and dichlorodiphenyldichloroethylene (DDE) adversely affects birth weight.

METHODS

We used maternal and cord blood and breast milk samples of 7,990 women enrolled in 15 study populations from 12 European birth cohorts from 1990 through 2008. Using identical variable definitions, we performed for each cohort linear regression of birth weight on estimates of cord serum concentration of PCB-153 and p,p´-DDE adjusted for gestational age and a priori selected covariates. We obtained summary estimates by meta-analysis and performed analyses of interactions.

RESULTS

The median concentration of cord serum PCB-153 was 140 ng/L (range of cohort medians 20-484 ng/L) and that of p,p´-DDE was 528 ng/L (range of cohort medians 50-1,208 ng/L). Birth weight decreased with increasing cord serum concentration of PCB-153 after adjustment for potential confounders in 12 of 15 study populations. The meta-analysis including all cohorts indicated a birth weight decline of 150 g [95% confidence interval (CI): -250, -50 g] per 1-µg/L increase in PCB-153, an exposure contrast that is close to the range of exposures across the cohorts. A 1-µg/L increase in p,p´-DDE was associated with a 7-g decrease in birth weight (95% CI: -18, 4 g).

CONCLUSIONS

The findings suggest that low-level exposure to PCB (or correlated exposures) impairs fetal growth, but that exposure to p,p´-DDE does not. The study adds to mounting evidence that low-level exposure to PCBs is inversely associated with fetal growth.

Biomonitoring and biomarkers to unravel the risks from prenatal environmental exposures for later health outcomes

An increasing number of studies have addressed the concern that environmental pollutants may contribute to the early origin of diseases. Epidemiologic studies suggest that prenatal exposure to air pollutants, several food contaminants, and chemicals present in consumer products are associated with nongenetically transmitted adverse health effects, which manifest after birth. Changes in neurobehavior, sexual development, the prevalence of asthma and allergy, and growth curves have been shown to be associated with pollutant exposure at early life stages. This review focuses on human molecular epidemiologic studies that contribute knowledge by introducing biomarker measurements to obtain a mechanistic understanding of the relation between early life exposures and health outcome. It has been hypothesized that subtle effects induced by pollutant exposure during development can lead to functional deficits and altered programming, which leads to increased disease or dysfunction risk later in life. Biomarker analysis may provide sensitive tools to trace these subtle changes and obtain mechanistic insight about the causal pathway between external exposure and health effects in human population studies. Biomarkers of exposure can be measured in mothers before conception, during pregnancy, or after birth. Different biological tissues-such as peripheral or cord blood samples, hair samples, meconium, and urine-provide specific information that reflects the actual dose during pregnancy or at birth. Biomarkers of effect may include changes in hormone concentrations, oxidative stress variables, changes in gene expression levels, and epigenetic changes.

Maternal fish consumption, fetal growth and the risks of neonatal complications: the Generation R Study

Maternal fish consumption during pregnancy has been suggested to affect birth outcomes. Previous studies mainly focused on birth outcomes and did not study fetal growth during pregnancy. In a prospective cohort study from early pregnancy onwards in The Netherlands, we assessed the associations of first-trimester maternal total-fish, lean-fish, fatty-fish and shellfish consumption with fetal growth characteristics in the second and third trimesters, growth characteristics at birth and the risks of neonatal complications, including pre-term birth, low birth weight and small for gestational age. In total, 3380 mothers completed a 293-item semi-quantitative FFQ to obtain information about fish consumption during the first trimester of pregnancy. Head circumference, femur length and fetal weight were estimated in the second and third trimesters by ultrasound. Information about birth anthropometrics and neonatal complications was available from hospital and midwife registries. Maternal older age, higher educational level, folic acid supplement use, alcohol use and not smoking were associated with higher fish consumption (P < 0·01). After adjustment, we observed no consistent associations of maternal total-fish consumption or specific consumption of lean fish, fatty fish or shellfish with fetal growth characteristics in the second and third trimesters and at birth. Likewise, total-fish consumption or specific consumption of any type of fish was not consistently associated with the risks of neonatal complications. These findings suggest that in a population with a relatively low fish intake, consumption of lean fish, fatty fish or shellfish in the first trimester is not associated with fetal growth or the risks of neonatal complications.

Partial linear inference for a 2-stage outcome-dependent sampling design with a continuous outcome

The outcome-dependent sampling (ODS) design, which allows observation of exposure variable to depend on the outcome, has been shown to be cost efficient. In this article, we propose a new statistical inference method, an estimated penalized likelihood method, for a partial linear model in the setting of a 2-stage ODS with a continuous outcome. We develop the asymptotic properties and conduct simulation studies to demonstrate the performance of the proposed estimator. A real environmental study data set is used to illustrate the proposed method.

Prenatal exposure to organochlorine compounds and neonatal thyroid stimulating hormone levels

It has been suggested that prenatal exposure to some organochlorine compounds (OCs) may adversely affect thyroid function and may, therefore, impair neurodevelopment. The main aim of this study was to examine the relationship of cord serum levels of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (4,4'-DDT), 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (4,4'-DDE), β-hexachlorocyclohexane (β-HCH), hexachlorobenzene (HCB), four individual polychlorobiphenyl (PCB) congeners (118, 138, 153, and 180), and their sum, with neonatal thyroid stimulating hormone (TSH) levels in blood samples in a mother-infant cohort in Valencia, Spain. This study included 453 infants born between 2004 and 2006. We measured OC concentrations in umbilical cord serum and TSH in blood of newborns shortly after birth. Associations between neonatal TSH levels and prenatal OC exposure adjusted for covariates were assessed using multivariate linear regression analyses. Neonatal TSH levels tended to be higher in newborns with β-HCH levels in umbilical cord above 90th percentile (104 ng/g lipid) than in those with levels below the median (34 ng/g lipid), with an adjusted increment in neonatal TSH levels of 21% (95% confidence interval=-3, 51; P=0.09). No statistically significant association was found between the remaining OCs and TSH at birth. Prenatal exposure to β-HCH may affect neonatal thyroid hormone status and its function in neurological development.

Benefits versus risks associated with consumption of fish and other seafood

Fish provide nutrition for much of the world's population, and when not contaminated with chemicals, fish is a very good food. A major benefit of fish is that they are high in polyunsaturated fatty acids (PUFAs), low in saturated fat, and they contain other critical nutrients. Much of the benefit of fish consumption derives from their high levels of long chain omega-3 PUFAs, which are produced by aquatic microorganisms and bioconcentrate in the aquatic food supply. The PUFAs are essential, in that humans and other vertebrates are not able to synthesize them and therefore must obtain them from the diet. The PUFAs particularly concentrate in the nervous system, alter immune system function reduce serum triglyceride levels and have been reported to reduce the risk of sudden death after a myocardial infarction. But the problem is that most fish have at least some degree of chemical contamination with methylmercury, (which binds to muscle) and/or with persistent organic pollutants such as dioxins, polychlorinated biphenyls, polybrominated diphenyl ethers, chlorinated pesticides (which concentrate in fish fat). These chemicals have adverse effects on nervous system function, modulate the immune system, and are associated with elevations in risk of cardiovascular disease. Thus the question of benefits and risk from fish consumption is complex but very important.

Environmental exposures and development

PURPOSE OF REVIEW

Summarize recent studies exploring the relationship between paternal and maternal environmental exposures to chemicals before, at the time of and after conception to adverse developmental outcomes including preterm birth, death, structural and functional abnormalities and growth restriction.

RECENT FINDINGS

Recent studies have demonstrated that human pregnancy and development are vulnerable to environmental exposures of the father and mother to chemical, biological and physical agents. Exposures associated with adverse developmental outcomes include air and water pollution, chemicals in foods, occupational exposures, agricultural chemicals, metals, persistent and volatile organics. Developmental endpoints which are linked with these exposures include growth restriction, functional abnormalities, structural abnormalities, preterm delivery and death. Despite this general understanding we still have incomplete knowledge concerning most exposures and the biological interactions responsible for impaired development and preterm delivery.

SUMMARY

Whereas single genes and individual chemical exposures are responsible for some instances of adverse pregnancy outcome or developmental disease, gene-environment interactions are responsible for the majority. These gene-environment interactions may occur in the father, mother, placenta or fetus, suggesting that critical attention be given to maternal and paternal exposures and gene expression as they relate to the mode of action of the putative developmental toxicant both prior to and during pregnancy.

Maternal serum preconception polychlorinated biphenyl concentrations and infant birth weight

BACKGROUND

Prenatal and postnatal polychlorinated biphenyl (PCBs) exposure has been associated with decrements in fetal and infant growth and development, although exposures during the preconception window have not been examined despite recent evidence suggesting that this window may correspond with the highest serum concentrations.

OBJECTIVES

We assessed maternal serum PCB concentrations at two sensitive developmental windows in relation to birth weight.

METHODS

Serum samples were collected from 99 women as they began trying to become pregnant (preconception) and after a positive pregnancy test (prenatal); 52 (53%) women gave birth and represent the study cohort. Using daily diaries, women recorded sexual intercourse, menstruation, and home pregnancy test results until pregnant or up to 12 menstrual cycles with intercourse during the estimated fertile window. With gas chromatography with electron capture, 76 PCB congeners were quantified (nanograms per gram serum) and subsequently categorized by purported biologic activity. Serum PCBs were log-transformed and entered both as continuous and categorized exposures along with birth weight (grams) and covariates [smoking (yes/no), height (inches), and infant sex (male/female)] into linear regression.

RESULTS

A substantial reduction in birth weight (grams) was observed for women in the highest versus the lowest tertile of preconception antiestrogenic PCB concentration (beta; = 429.3 g, p = 0.038) even after adjusting for covariates (beta; = 470.8, p = 0.04).

CONCLUSIONS

These data reflect the potential developmental toxicity of antiestrogenic PCBs, particularly during the sensitive preconception critical window among women with environmentally relevant chemical exposures, and underscore the importance of PCB congener-specific investigation.

Fish consumption during pregnancy, prenatal mercury exposure, and anthropometric measures at birth in a prospective mother-infant cohort study in Spain

BACKGROUND

Birth size has been shown to be related to maternal fish intake, although the results are inconsistent.

OBJECTIVE

The objective was to assess the association of consumption of different types of fish and prenatal mercury exposure with birth weight, birth length, and classification as small for gestational age (SGA) in newborns.

DESIGN

Cord blood total mercury was measured in 554 newborns in a population-based cohort born from 2004 to 2006. Fish consumption was classified in 4 frequency categories (<1 portion/mo, 1-3 portions/mo, 1 portion/wk, and > or =2 portions/wk).

RESULTS

When multivariate models were adjusted, newborns in the higher quartile of total mercury weighed 143.7 g less (95% CI: -251.8, -35.6; P for trend = 0.02) and had higher odds of being SGA for length (odds ratio: 5.3; 95% CI: 1.2, 23.9; P from likelihood ratio test = 0.03) without a linear relation (P for trend = 0.13) compared with those in the lowest quartile. Mothers consuming >/=2 portions/wk of canned tuna had newborns who weighed more than those who consumed <1 portion/mo (P for trend = 0.03) and a lower risk of having infants who were SGA for weight (P for trend = 0.01). Consumption of > or =2 portions/wk of large oily fish was associated with a higher risk of being SGA for weight and consumption of lean fish with a lower risk of being SGA for length compared with the consumption of <1 portion/mo, but in neither case was there a linear relation (P for trend >0.05).

CONCLUSIONS

The role of fish in fetal growth depends on the amount and type of fish consumed. The findings for mercury warrant further investigation in other settings.