Associations of polybrominated diphenyl ethers (PBDEs) in breast milk and dietary habits and demographic factors in Taiwan

Mollusc and crustacean consumption in the first 1000 days: a scoping review

Mollusc and crustacean consumption in the first 1000 d may improve maternal and child health by providing essential nutrients. However, in some contexts, molluscs and crustaceans have been associated with allergies and environmental contamination, potentially leading to adverse health and development outcomes. It is unclear whether the health benefits of consuming molluscs and crustaceans, collectively classified as shellfish in nutrition, are outweighed by the potential risks to pregnant women and children. We conducted a scoping review (PROSPERO: CRD42022320454) in PubMed, Scopus and EBSCO Global Health of articles published between January 2000 and March 2022 that assessed shellfish consumption during pregnancy, lactation or childhood (0-2 years) in relation to maternal health, child health or child development. A total of forty-six articles were included in this review. Overall, shellfish consumption was associated with higher biomarkers of environmental contaminants, with mercury being the most studied and having the strongest evidence base. The limited research on nutritional biomarker status shows an association between shellfish consumption and iodine status. Preterm birth was not associated with shellfish consumption, but newborn anthropometry showed mixed results, with several studies reporting lower birth weight with higher shellfish consumption. The few studies that examined child development and maternal health outcomes reported no significant associations. This review revealed trade-off health risks and benefits with inclusion of molluscs and crustaceans in the dietary patterns of mothers and young children. More research is needed to understand how these aquatic animal-source foods may be safely consumed and leveraged for improving human nutrition.

Has Regulatory Action Reduced Human Exposure to Flame Retardants?

Flame retardant (FR) exposure has been linked to several environmental and human health effects. Because of this, the production and use of several FRs are regulated globally. We reviewed the available records of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDDs) in human breast milk from literature to evaluate the efficacy of regulation to reduce the exposure of FRs to humans. Two-hundred and seven studies were used for analyses to determine the spatial and temporal trends of FR exposure. North America consistently had the highest concentrations of PBDEs, while Asia and Oceania dominated HBCDD exposure. BDE-49 and -99 indicated decreasing temporal trends in most regions. BDE-153, with a longer half-life than the aforementioned isomers, typically exhibited a plateau in breast milk levels. No conclusive trend could be established for HBCDD, and insufficient information was available to determine a temporal trend for BDE-209. Breakpoint analyses indicated a significant decrease in BDE-47 and -99 in Europe around the time that regulation has been implemented, suggesting a positive effect of regulation on FR exposure. However, very few studies have been conducted globally (specifically in North America) after 2013, during the time when the most recent regulations have been implemented. This meta-analysis provides insight into global trends in human exposure to PBDEs and HBCDD, but the remaining uncertainty highlights the need for ongoing evaluation and monitoring, even after a compound group is regulated.

Analysis of Polybrominated Diphenyl Ethers and Lipid Composition in Human Breast Milk and Their Correlation with Infant Neurodevelopment

Breastfeeding is recommended over formula feeding, but human breast milk (HBM) composition varies and can be affected by food additives. Whether flame-retardant polybrominated diphenyl ethers (PBDEs) found in HBM interact with lipid components of HBM to impede infant neurodevelopment is a critical public health issue. Using lipidomic analysis, we examined the association of PBDEs in HBM and HBM lipid components with infant neurodevelopment. HBM samples (n = 100) were collected at the beginning stage of breastfeeding and analyzed for 30 PBDE congeners as well as a group of lipid components by using high-resolution gas chromatography, mass spectrometry, and liquid chromatography time-of-flight mass spectrometry. Infants were examined at 8 to 12 months of age by using the Bayley-III to assess neurodevelopment. A total of seven PBDEs, 35 lipids, and 27 fatty acids in HBM showed significant associations with Bayley-III scores. Multivariate analysis confirmed that these candidate PBDEs and lipid components were significant predictors of infant neurodevelopment. Eicosapentaenoic acid and docosapentaenoic acid in HBM showed no association with infant neurodevelopment in the general Taiwanese population. While certain PBDEs may play a role, our findings indicate that the lipid components of HBM are directly important for infant neurodevelopment.

Associations between in utero exposure to polybrominated diphenyl ethers, pathophysiological state of fetal growth and placental DNA methylation changes

BACKGROUND

Polybrominated diphenyl ethers (PBDEs) are environmental chemicals with harmful effects on pregnancy, but their effects on adverse developmental outcomes are not fully understood. The placental DNA methylation is strongly influenced by prenatal environmental factors and has been linked to fetal growth.

OBJECTIVE

To evaluate the association between in utero PBDEs exposure, placental DNA methylation changes (growth regulatory genes), and pathophysiology of fetal growth (birth outcomes, fetal growth retardation) in a population-based pregnancy cohort study.

METHODS

This was a nested case-control study within the prospective Wenzhou Birth Cohort including 130 fetal growth retardation (FGR) cases and 130 healthy controls and their mothers recruited from June 2016 to June 2017. FGR was diagnosed based on the comprehensive evaluation of ultrasound results at 24, 28, and 32 weeks of gestation. Neonatal birth measurements were obtained from medical records. Gestational exposure to 19 PBDEs, including 13 lower BDE congeners (BDE-17-190) and 6 higher brominated BDE congeners (BDE-196-209), were determined by gas chromatography tandem mass spectrometry in the umbilical cord blood. Placental DNA methylation changes of one repetitive element (LINE1) and two candidate genes (HSD11B2, IGF2) were characterized by quantitative polymerase chain reaction-pyrosequencing. Multiple linear regression and logistic regression models were used to examine the associations among PBDEs exposure, fetal growth indicators, and DMR (differential methylation region) methylation fractions. Sobel tests were conducted to assess DNA methylation as a mediator in multivariate models.

RESULTS

After excluding women who withdrew from the study or were lost to follow-up or failed to provide placenta or umbilical cord blood, 249 mother-newborn pairs (124 FGR cases, 125 controls) were included in the final analysis. Elevated BDE-206 (OR: 1.569, 95% CIs: 1.053-2.338), BDE-17-190 (OR: 2.860, 95% CIs: 1.233-6.634), BDE-196-209 (OR: 1.688, 95% CIs: 1.024-2.783) and ∑₁₉PBDEs (OR: 2.387, 95% CIs: 1.220-4.668) concentrations were associated with increased risk of FGR in newborns. FGR birth was also associated with increased DNA methylation of HSD11B2 (OR: 1.145, 95% CIs: 1.032-1.270) and decreased DNA methylation of IGF2 (OR: 0.892, 95% CIs: 0.845-0.941). In addition, BDE-17-190 showed significant associations with DNA methylation of HSD11B2 and IGF2 (β: 1.127, 95% CIs: 0.069-2.186; β: -3.452, 95% CIs: -5.512-1.392), indicating placental DNA methylation changes of HSD11B2 and IGF2 were related to both lower BDE congeners exposure and fetal growth. Further mediation analyses showed that IGF2 methylation mediated about 40% of the effects of BDE-17-190 in umbilical cord blood on neonatal FGR.

CONCLUSION

We report an inverse association between in utero exposures to PBDEs and fetal growth and provide evidence supporting epigenetic gene plasticity in these associations. Changes in placental DNA methylation might be part of the underlying biological pathway between prenatal PBDEs exposure and adverse fetal growth.

Levels of PCDD/Fs, PBDEs, and PBDD/Fs in Breast Milk from Southern Taiwan

This study investigates the congener-specific concentrations of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), polybrominated dibenzo-p-dioxins/furans (PBDD/Fs), and polybrominated diphenyl ethers (PBDEs) in 25 breast milk samples from southern Taiwan. Most investigated congeners in Taiwanese breast milk are detectable except for PBDD/Fs. The geometric means of PCDD/Fs and PBDEs in the breast milk are 2.44 pg WHO₂₀₀₅-TEQ/g lipid and 2810 pg/g lipid. Several PCDD/F and PBDE congeners were highly correlated to each other like 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDF (r = 0.919, p < 0.001). The longest duration of menstruation could be predicted by BDE-153 (β = 0.252) and 1,2,3,4,6,7,8-HpCDF (β = 0.345) with adjustment of confounders using a multiple stepwise linear regression model (r = 0.963, p < 0.001).

Distribution of polybrominated diphenyl ethers in breast milk, cord blood and placentas: a systematic review

Polybrominated diphenyl ethers (PBDEs) have been extensively used as flame retardants in consumer products. PBDEs rapidly bioaccumulate in the environment, food, wild animals and humans. In this review, we investigated the harmful effects of PBDEs on humans, especially in early life, and summarised the levels of PBDEs in human biological samples (breast milk, cord blood and placentas). In addition, we described the spatiotemporal distribution of PBDEs in this review. PBDE levels in breast milk, cord blood and placentas were generally higher in North America than in other regions, such as Asia, Europe, Oceania and Africa. However, high levels of PBDEs in human biological samples were detected at e-waste recycling sites in South China, East China and South Korea. This finding suggests that newborns living in e-waste regions are exposed to high levels of PBDEs during prenatal and postnatal periods. The time trends of PBDE concentration differed according to the region. Few studies have investigated PBDE levels in humans from 1967 to 2000, but they increased rapidly after 2000. PBDE concentration peaked at approximately 2006 globally. Compared with other PBDE congeners, BDE-47, BDE-153 and BDE-209 were the major components, but the detection rate of BDE-209 was lower than those of others. Future studies should focus on determining the BDE-209 concentration, which requires the implementation of different analytical approaches. Additionally, the levels of PBDEs in human samples and the environment should be monitored, especially in e-waste recycling regions. Graphical abstract The figures described the spatial distribution of the lowest (Fig. a1) and highest concentration of ∑PBDE (Fig. a2) in different countries by 2006 and described the spatial distribution of the lowest (Fig. b1) and highest concentration of ∑PBDE (Fig. b2) in different countries from 2007 to 2015. All the figures indicated that the levels of PBDEs in North America were substantially higher than those in many regions of Europe, Asia, Oceania, or Africa. Comparing Fig. a1-b1 or Fig. a2-b2, increasing trends were observed in some countries, especially in some regions in China, Korea and Canada.

Umbilical cord blood PBDEs concentrations are associated with placental DNA methylation

BACKGROUND

In utero polybrominated diphenyl ethers (PBDEs) exposure has been associated with adverse fetal growth. Alterations in placental DNA methylation might mediate those adverse effects.

OBJECTIVES

To examine the associations between in utero PBDEs exposure and DNA methylation in human placenta.

METHODS

Eighty apparently healthy mother-newborn pairs delivering at the Second Affiliated Hospital of Wenzhou Medical College were enrolled in this study. Placental DNA methylation of LINE1, NR3C1 and IGF2 was measured by quantitative polymerase chain reaction-pyrosequencing. In utero PBDEs exposure was assessed by measuring umbilical cord blood PBDEs concentrations.

RESULTS

For LINE-1, higher levels of BDE-66 exposure were associated with decreased DNA methylation (β=-0.9, 95% CI, -1.8 to -0.1); For NR3C1, BDE-153 concentrations was significantly inversely associated with DNA methylation (β=-2.0, 95% CI, -3.7 to -0.2); For IGF2, elevated concentrations of both BDE-153 (β=-1.7; 95% CI, -3.0 to -0.4) and BDE-209 (β=-1.0; 95% CI, -1. 9 to -0.1) were significantly associated with decreased DNA methylation.

CONCLUSIONS

We found that placental DNA methylation is associated with in utero PBDEs exposure. Changes in placental DNA methylation might be part of the underlying biological pathway between in utero PBDEs exposure and adverse fetal growth.

Persistent Organic Pollutants and Concern Over the Link with Insulin Resistance Related Metabolic Diseases

Persistent organic pollutants (POPs) are mostly halogenated compounds tending to persist in the environment, enter into the food chain, and accumulate in fat mass of mammals due to their high lipophilicity. They include some organochlorine pesticides, polychlorinated biphenyls, brominated flame retardants and polycyclic aromatic hydrocarbons. Some of these chemicals were widely used in the past so that their residues can be detected in the human body, though their usage has been banned for years. POPs have been shown to perturb the health of biological systems in different ways evidenced by carcinogenicity and disrupting effects on endocrine, immune, and reproductive systems. There are many epidemiologic and experimental studies on the association of exposure to POPs with insulin resistance and related metabolic disorders like obesity, diabetes, and metabolic syndrome. Inflammation as a known mechanism accompanying insulin resistance has also been shown to arise in insulin target tissues exposed to POPs. This review addresses the breast milk concentration of POPs in different regions of the world, synthesizes the current information on the association of POPs with insulin resistance related metabolic disorders, and discusses the inflammation as an involved mechanism. Considering high prevalence of insulin resistance related metabolic diseases and their relation with POPs, much need is felt regarding international and regional programs to not only limit their production and usage but eliminate these persistent pollutants from the environment.

Polybrominated biphenyl ethers in breast milk and infant formula from Shanghai, China: temporal trends, daily intake, and risk assessment

To investigate the temporal trend of polybrominated diphenyl ethers (PBDEs) in breast milk and assess the risks to breast- and formula-fed infants, breast milk and infant formula samples were collected from Shanghai, China. The PBDE concentrations decreased from 14.8 to 4.85 pmol/g lipid weight during 2006-2012, with a rate of decrease by half approximately every four years. Although there were no significant correlations between the total PBDEs in breast milk and age, parity, and pre-pregnant BMI of mothers, there were significant differences between primiparous and multiparous mothers for tri- to hepta-BDEs. PBDEs in breast milk were much higher than those in infant formula (equivalent to 91.9 vs. 5.25 pg/mL). Among the different brand infant formulas, there were no significant differences in their PBDE concentrations. The estimated daily intake of PBDEs by breast- and formula-fed infants suggested that breast-fed infants are exposed to much more PBDEs than formula-fed ones (12.9 vs. 0.72 ng/kg-bw/day). However, the hazard quotient values were much smaller than one, indicating that the ingested PBDEs did not exert obvious adverse effects on both breast- and formula-fed infants considering non-carcinogenic effect endpoint. This is the first report on temporal trend of PBDEs in breast milk from China.

Levels of tetrabromobisphenol A, hexabromocyclododecanes and polybrominated diphenyl ethers in human milk from the general population in Beijing, China

Three brominated flame retardants (BFRs), tetrabromobisphenol A (TBBPA), hexabromocyclododecane (HBCD) and polybrominated diphenyl ethers (PBDEs), were measured in 103 human milk samples collected from Beijing in 2011. The donors' personal information, such as dietary habit and socioeconomic and lifestyle factors, was obtained by questionnaires. Ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS) analysis indicated that the levels of TBBPA ranged from <LOD to 12.46 ng g(-1) lipid weight (lw), with a median value of 0.10 ng g(-1) lw. Three HBCD diastereoisomers (α-, β- and γ-HBCD) were also measured using UPLC-MS/MS. The levels of ΣHBCDs ranged from <LOD to 78.28 ng g(-1) lw, with a median value of 2.40 ng g(-1) lw. α-HBCD was generally the most abundant of the three isomers. Eight PBDE congeners, BDE-28, 47, 99, 100, 153, 154, 183 and 209, were measured using gas chromatography coupled with a mass spectrometry (GC/MS). The concentrations of ΣPBDEs ranged from 0.22 to 135.41 ng g(-1) lw, with a median value of 3.24 ng g(-1) lw. BDE-209 dominated the PBDE profile in the majority of the human milk samples. The mean estimated daily intakes (EDIs) of TBBPA, ΣHBCDs and ΣPBDEs by breast-fed infants were 2.34, 24.89 and 71.27 ng kg(-1) bw day(-1), respectively. No significant correlation was found between the BFR levels in milk and the mother's diet, place of residence, smoking habit, nursing duration or computer use habit. In contrast, the mother's age, body mass index (BMI), education level and number of computers in the home were related to the levels of some types of BFRs. More research is needed to further investigate the major source(s) of exposure, the effect of each potential factor and the possible toxicological impact of high daily BFR intake on infants.

Neurodevelopment of infants with prenatal exposure to polybrominated diphenyl ethers

The study aimed to examine the impact of prenatal exposure to polybrominated diphenyl ethers (PBDEs) on infant neurodevelopment. PBDEs levels in 36 cord blood samples were analyzed with a high-resolution-gas-chromatograph/high-resolution-mass-spectrometer and infant neurodevelopment was assessed using the Bayley Scales of Infant and Toddler Development, Third Edition. The mean and median of Σ(11)PBDEs were 6.63 and 4.63 ng/g lipid, respectively. As compared to the lower PBDEs group (Σ(11)PBDEs < 4.63 ng/g lipid), the higher PBDEs group (Σ(11)PBDEs > 4.63 ng/g lipid) had a significantly higher actual odds ratio (OR = 1.13, p < 0.05) of the cognition score as well as a lower odds ratio (OR = 0.904, p < 0.01) of the adaptive behavior score, suggesting that prenatal PBDEs exposure may potentially affect infant neurodevelopment.

Cord blood levels of thyroid hormones and IGF-1 weakly correlate with breast milk levels of PBDEs in Taiwan

In vivo studies indicate that prenatal or neonatal exposure of rodents to polybrominated diphenyl ethers (PBDEs) disrupts thyroid hormone balance, but few studies have reported an association of PBDEs and insulin-like growth factor 1 (IGF-1). The goal was to examine whether PBDEs exposure affects the levels of thyroid hormones and IGF-1 in cord blood. Study participants were healthy pregnant women recruited from the general population in central Taiwan between 2000 and 2001 and in southern Taiwan from 2007 to 2009. One-hundred-forty-nine breast milk samples (n=149), which were collected within one month after delivery, were analyzed using a high resolution gas chromatograph equipped with a high resolution mass spectrometer. The average and median levels of breast milk Σ(14)PBDEs were 5.34 and 3.38 ng/g lipid in 2000-2001 and 5.22 and 3.13 ng/g lipid in 2007-2009, respectively. In general, levels of PBDE congeners were very low in this study population and not significantly different between the years 2000-2001 and 2007-2009. Breast milk Σ(14)PBDEs were not significantly correlated with thyroid hormones and IGF-1 in cord blood. After examining multiple stepwise linear regression models with adjustment for maternal age, pre-pregnancy body mass index (BMI), parity, gestational age, and region (namely, central and southern Taiwan), we found that log of T4 in cord blood was significantly but slightly correlated with higher BDE-154 (B=0.113, p=0.017) in breast milk. The log of FT4 concentration was significantly related to a decrease in the log of BDE-99 level (B=-0.137, p=0.043) and an increase in the log of BDE-154 level (B=0.158, p=0.008). Meanwhile, the log of IGF-1 level was also significantly linked to an increase in the log of BDE-196 level (B=0.532, p=0.028) and decrease in the log of BDE-85 level (B=-0.235, p=0.018). Few epidemiological studies report an association between PBDEs exposure and IGF-1. Based on our findings, further in vivo and epidemiological studies are encouraged and needed to explore associations between PBDEs exposure and levels of thyroid hormones and IGF-1.

Human maternal and umbilical cord blood concentrations of polybrominated diphenyl ethers

Polybrominated diphenyl ethers (PBDEs), widely used as flame retardants in commercial products, have become ubiquitous environmental contaminants. Although adult human exposure to PBDEs is well documented, developmental exposure is less well characterized. The objectives of this study were to measure maternal and fetal exposure to nine PBDE congeners and to investigate potential associations with birth weight. PBDE congeners were quantified in maternal serum at 24-28 weeks of pregnancy, delivery, and umbilical cord serum (UCS) by gas chromatography-mass spectrometry (GC/MS/MS). Complete blood sample sets were obtained from 97 pregnant women (mean age 33.1±0.5 years). PBDE-28, -47 and -99 were quantified in all samples tested and PBDE-47 was the most abundant congener measured in both maternal (mid-pregnancy and delivery samples geometric mean=26.9 and 26.9, respectively) and UCS (GM=56.0 ng g(-1) lipid). The UCS concentration for all congeners with the exception of PBDE-153 was higher vs. maternal delivery samples (p<0.001). Only the UCS concentration of PBDE-17 and -99 were significantly associated (β=-49.860, p=0.032, and β=-3.645, p=0.05) with birth weight. However, after adjustment for potential confounders only the association between PBDE-99 and birth weight remained significant (β=-3.951 and p=0.016). We conclude that: the fetus is exposed to PBDEs from at least the second trimester of pregnancy onward; PBDE congeners are higher in UCS compared to maternal serum samples collected at delivery; and that developmental PBDE exposure is potentially associated with lower birth weight.

Levels of brominated flame retardants and other pesistent organic pollutants in breast milk samples from Limpopo Province, South Africa

The non-occupational exposure to brominated flame retardants, and other persistent organic pollutants (POPs) was studied by collecting human breast milk samples from mothers residing in Thohoyandou area, a rural district in the Limpopo Province, northern part of South Africa (SA). Of all collected samples to be analysed (n=28), those with large enough milk volumes, (n=14) were quantified for polybrominated diphenyl ethers (PBDEs) (9 congeners: BDE-28, 47, 66, 99, 100, 138, 153, 154, and 183) and hexabromocyclododecane (HBCD) on a GC equipped with dual capillary columns and dual electron-capture detectors (ECD). The levels of PBDE congeners (median sumBDE 1.3 ng/g of lipids) and of HBCD were not far from levels generally found in European studies, and this study may be the first report on the presence of PBDEs and HBCD in SA breast milk. On a congener basis, the finding of comparably high BDE-183 levels suggests a specific PBDE usage, or contamination situation in SA. Apart from BFRs, the high DDT levels found in the breast milk from this area (median and maximum sumDDT levels of about 4600 and over 20,000 ng/g of lipids, respectively; n=28) have earlier been reported. In addition, other POPs (PCBs, HCB and HCHs) were found in SA breast milk, at relatively low levels. To conclude, measurable levels of PBDEs and HBCD, and a specific BDE congener pattern, were found in breast milk from the Limpopo province, SA. A number of other POPs, including DDTs in high levels, were also present.

A national survey of polybrominated diphenyl ethers (PBDEs) and indicator polychlorinated biphenyls (PCBs) in Chinese mothers' milk

Seven polybrominated diphenyl ethers (PBDEs) congeners (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154 and BDE-183) and six indicator polychlorinated biphenyls (PCBs) congeners (CB-28, CB-52, CB-101, CB-138, CB-153 and CB-180) were measured in 24 pooled human milk samples comprised of 1237 individual samples from 12 provinces in China. The samples were taken to estimate the background body burden of general population and assess nursing infant exposure via human milk in China. The median concentrations of ∑(7)PBDEs and ∑(6)PCBs were 1.49 and 10.50 ng g(-1) lipid weight (lw), respectively. BDE-28, BDE-47 and BDE-153 were predominant PBDE congeners accounting for nearly 70% of ∑(7)PBDEs. As for indicator PCBs, CB-153 was the most abundant congener, followed by CB-138. In our study, there was no significantly statistical relationship between concentrations of PBDEs in milk samples and maternal age as well as dietary habits. ∑(7)PBDEs did not correlate to ∑(6)PCBs in Chinese mothers' milk. The human exposure to indicator PCBs in China was found to be significantly determined by maternal age, dietary habits and geographical factors. It is suggested that Chinese general population is probably exposed to PBDEs with multiple sources and pathways. The estimated daily intakes (EDI) of BDE-47, BDE-99 and BDE-153 for the Chinese nursing infant were much lower than corresponding threshold reference values suggested by USEPA.

Negative associations between PBDE levels and thyroid hormones in cord blood

Polybrominated diphenyl ethers (PBDEs) causing thyroidal effects have been demonstrated in in vivo and in vitro studies. PBDEs with structural similarities to thyroid hormones have increased recently, but the health effects for thyroid hormones have not been well studied. The study aimed to determine PBDE levels in cord blood and further to explore associations between prenatal PBDE exposures and thyroid hormones in cord blood. Fifty-four cord blood samples were collected after delivery. Cord-blood levels of BDE-15, 28, 47, 99, 100, 153, 154, and 183 were analyzed using a high resolution gas chromatograph with a high resolution mass spectrometer. Thyroid hormones were determined by an automated chemiluminescence analyzer. The mean, median, and standard deviation of ΣPBDEs were 4.72, 3.49, and 6.36 ng/g lipid, respectively. To adjust for confounding by maternal age, pre-pregnant BMI and gestational age, stepwise multiple linear regression was used after log(2) transformation of the exposure variables. A doubling of BDE-154 was associated with 0.043 ng/mL lower triiodothyronine (T3) values (adjusted r=-0.245, p=0.043). Likewise a doubling of BDE-153 was associated with 0.143 ng/mL lower free T3 (FT3) values and a doubling of BDE-183 with 0.084 ng/mL lower FT3 values (adjusted r=-0.487, p=0.023). In contrast, the T4 (thyroxine)/T3 ratio increased by 4.93 (adjusted r=0.277, p=0.017) when doubling BDE-100 exposure. No significant associations with BDE-47 or any other of the PBDEs was found. Our findings of an inverse relationship between BDE-153, BDE-154 or BDE-184 and thyroid hormones confirm the results of animal experiments but are in contrast to most epidemiological studies.

Impact of non-occupational exposure to polybrominated diphenyl ethers on menstruation characteristics of reproductive-age females

Polybrominated diphenyl ethers (PBDEs) have documented effects on thyroid functions and rodent behavior in vivo. Epidemiological studies, however, have revealed only limited information about associations between PBDE exposure and menstruation characteristics. Our goal was to examine whether high breast milk PBDE levels in reproductive-age females lead to interference with menstruation characteristics. We analyzed 15 PBDE congeners in 46 breast milk samples. Fifteen PBDE congeners (BDE-15, 28, 47, 49, 99, 100, 153, 154, 183, 196, 197, 203, 207, 208, and 209) were analyzed using a gas chromatograph equipped with a high resolution mass spectrometer. The mean sum of PBDEs (SigmaPBDEs) in breast milk was 3.42 ng/g lipid. Women's age at menarche was not correlated with breast milk PBDE levels. Increased BDE-208 and 209 levels were significantly associated with the prolonged length of average and the longest menstrual cycle independent of age, pre-pregnant BMI, and parity. Higher concentrations of SigmaPBDEs and the higher brominated PBDEs from BDE-183 to 209, except 197, were significantly linked to women whose menstruation periods were still coming irregularly at the sampling time. Age-adjusted odds ratios (ORs) of BDE-153, 183, 207, 208, and SigmaPBDEs were significantly higher in women with length of average menstrual cycle >32 days, compared to the control. Women whose menstruation periods still came irregularly when they were 18 years old had higher age-adjusted ORs of BDE-207, 208, 209, and SigmaPBDEs than those whose periods came regularly at the same age. Although SigmaPBDEs and certain higher brominated PBDEs appear to have potential to prolong length of average menstrual cycle and delay the age when menstruation periods begin coming regularly, these findings are not conclusive because our sample size is small and more scientific evidence is needed.

Application of mass spectrometry in the analysis of polybrominated diphenyl ethers

This review summarized the applications of mass spectrometric techniques for the analysis of the important flame retardants polybrominated diphenyl ethers (PBDEs) to understand the environmental sources, fate and toxicity of PBDEs that were briefly discussed to give a general idea for the need of analytical methodologies. Specific performance of various mass spectrometers hyphenated with, for example, gas chromatograph, liquid chromatograph, and inductively coupled plasma (GC/MS, LC/MS, and ICP/MS, respectively) for the analysis of PBDEs was compared with an objective to present the information on the evolution of MS techniques for determining PBDEs in environmental and human samples. GC/electron capture negative ionization quadrupole MS (GC/NCI qMS), GC/high resolution MS (GC/HRMS) and GC ion trap MS (GC/ITMS) are most commonly used MS techniques for the determination of PBDEs. New analytical technologies such as fast tandem GC/MS and LC/MS become available to improve analyses of higher PBDEs. The development and application of the tandem MS techniques have helped to understand environmental fate and transformations of PBDEs of which abiotic and biotic degradation of decaBDE is thought to be one major source of Br(1-9)BDEs present in the environment in addition to direct loading from commercial mixtures. MS-based proteomics will offer an insight into the molecular mechanisms of toxicity and potential developmental and neurotoxicity of PBDEs.

PCB-153 exposure coordinates cell cycle progression and cellular metabolism in human mammary epithelial cells

2,2',4,4',5,5'-Hexachlorobiphenyl (PCB-153) is a non-metabolizable environmental chemical contaminant commonly found in breast milk of PCB exposed individuals, suggesting that chronic exposure to PCB-153 could have adverse health effects. We have shown previously that PCB-153 increased reactive oxygen species levels in non-tumorigenic MCF-10A human mammary epithelial cells, which were associated with DNA damage, growth inhibition, and cytotoxicity. This study investigates the hypothesis that PCB-153 exposure coordinates cell cycle progression and cellular metabolism by inhibiting cyclin D1 accumulation. PCB-153 treated MCF-10A cells exhibited a dose and time dependent decrease in cyclin D1 protein levels. The decrease in cyclin D1 protein levels was associated with an inhibition in AKT and GSK-3beta phosphorylation, which correlated with an increase in cyclin D1-T286 phosphorylation. Fibroblasts carrying a mutant form of cyclin D1 (T286A) were resistant to PCB-153 induced degradation of cyclin D1. Pre-treatment of cells with a proteasome inhibitor (MG132) suppressed PCB-153 induced decrease in cyclin D1 protein levels. Interestingly, suppression in cyclin D1 accumulation was associated with an increase in cellular glucose consumption, and hexokinase II and pyruvate kinase protein levels. These results suggest that cyclin D1 coordinates cell cycle progression and cellular metabolism in PCB-153 treated non-tumorigenic human mammary epithelial cells.

Concentrations of polybrominated diphenyl ethers in breast milk correlated to maternal age, education level, and occupational exposure

The aim of the present study is to determine whether levels of polybrominated diphenyl ethers in breast milk in the general population are associated with demographic parameters, socioeconomic status, lifestyle factors, and occupational exposure. Forty-six participants are randomly selected from healthy women recruited between April 2007 and April 2008 from local hospitals in southern Taiwan. Thirty PBDE isomers in breast milk are analyzed using a gas chromatograph with a high resolution mass spectrometer. The mean+/-standard deviation of Sigma PBDEs in breast milk is 3.59+/-1.07 ng/g lipid. Our current value of Sigma PBDEs in breast milk is 0.7-fold lower compared to the past value in our previous study between 2000 and 2001. Higher levels of Sigma PBDEs might be significantly associated with older maternal age and maternal age of the present study is between 22 and 42 years old. Levels of Sigma PBDEs and certain PBDEs in breast milk are not correlated with maternal pre-pregnant BMI (Body mass index), parity, and lipid contents of breast milk. The Sigma PBDEs level in breast milk is lower in more educated women after controlling for age and pre-pregnancy BMI in our subjects. The main factors associated with Sigma PBDEs in breast milk are age and education level among the binary variables of demographic, socioeconomic, and lifestyle characteristics in this report. The exploratory relationships are found between PBDEs in breast milk and age, education level, or occupational exposure due to small sampling size.

Polybrominated diphenyl ethers in umbilical cord blood and relevant factors in neonates from Guiyu, China

We aimed to evaluate the exposure of neonates to polybrominated diphenyl ethers (PBDEs) from a primitive e-waste (obsolete electrical and electronic devices) recycling area, in Guiyu, China, and a control area, Chaonan, China, through umbilical cord blood (UCB), the health effects, and relevant factors. Questionnaires were addressed, and UCB was collected shortly after birth from 153 pregnant women between May and July 2007. Blood samples were prepared by liquid-liquid extracting methods. PBDE concentration was determined by gas chromatography/mass spectrometry in the electron capture negative ionization mode. The total PBDE concentration was higher in UCB samples from Guiyu than in Chaonan samples (median 13.84, range 1.14-504.97 ng g(-1) lipid, vs 5.23, range 0.29-363.70 ng g(-1) lipid) (p < 0.05). BDE-209 was the dominant PBDE congener, followed by BDE-47, -153, and -99. Residence in Guiyu, which is a site for e-waste recycling, involvement in e-waste recycling, and the residence also being used as a family workshop were significant factors contributing to PBDE exposure. PBDE levels significantly differed in neonates by normal birth and adverse birth outcomes including stillbirth, low birth weight, and premature delivery (p < 0.05). The neonates from Guiyu are exposed to high levels of PBDEs. Prenatal exposure to PBDEs may affect neonates' health in Guiyu, which still needs to be evaluated in larger epidemiological studies.

Levels and regional trends of persistent organochlorines and polybrominated diphenyl ethers in Asian breast milk demonstrate POPs signatures unique to individual countries

Human breast milk samples collected in 2007-2008 from four countries, Vietnam (Hanoi), China (Beijing), Korea (Seoul) and Japan (Sendai, Kyoto and Takayama), were analyzed for persistent organic pollutants (POPs) such as dichlorodiphenyltrichloroethane and its metabolites (DDTs), chlordane-related compounds (CHLs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). Comparing with previous surveys, the present study indicates that the DDTs in breast milk from China and Vietnam had gradually decreased during the last decade, but were still 5-10 times higher than those in other nations. The ratios of p,p'-DDE/p,p'-DDT and o,p'-DDT/p,p'-DDT were higher in Beijing than in the other countries, suggesting that there is less fresh intake of commercial DDT products and a possible exposure to dicofol in China. CHL and PCB levels were relatively higher in mothers from Japan, whereas beta-HCH and HCB were more common in Chinese women. In Japan, it is suspected that mothers in the urban/coastal area (Sendai) were more continuously exposed to organochlorine pesticides (OCPs) than mothers in the rural/inland area (Takayama). In addition, OCP levels in primiparae were significantly higher than those in multiparae from Japan and Korea. These indicate that both parity and regional factors are major determinants of the levels of OCPs and PCBs in human milk. On the other hand, higher concentrations of PBDEs were observed in mothers' milk from Korea. The congener was dominated by BDE-47 (43-54%), followed by BDE-153 (23-33%) in all regions except for Beijing where BDE-28 (23%) was relatively abundant. In Japanese breast milk, regional and parity-dependent distributions were not observed for PBDEs. Among PBDE congeners, age-dependency was observed for BDE-153, which was negatively correlated (p<0.05) to the age of mothers in Kyoto (17 participants were housewives), while it increased with age in Sendai (10 participants were clerks). No such correlation was seen for BDE-47, indicating that BDE-47 was ingested and assimilated via different kinetics or routes from BDE-153 in Japan.

Exposure assessment of polybrominated diphenyl ethers (PBDEs) in Mexican children

Flame retardants (FRs) constitute a group of compounds that are added to materials in order to suppress, reduce, or delay fire. At present the most used FRs are the polybrominated diphenyl ethers (PBDEs), and diverse studies have found individuals exposed to them. However, few studies have reported data in children. The objective of this report was to assess PBDEs levels in children of six communities in México. During the year 2006 we analyzed a total of 173 healthy children (aged 6-13 years old). Plasma samples were taken and quantified (gas chromatography/mass spectrometer) for PBDEs. Six PBDEs congeners (BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, and BDE-209) were quantified in blood serum. We detected exposure to PBDEs in all the communities. The total PBDEs levels ranged from no detectable (nd) to 43.4 ng g(-1) lipid, the dominant PBDE congener was BDE-47, followed by BDE-100, BDE-99 and BDE-153, whereas the levels of BDE-209 were below LOD. Children living in an industrial and urban area (Cd. Juarez, Chih) had the highest levels of PBDEs, approximately two times that of children living in El Refugio, S.L.P. (a rural area) or in Milpillas, S.L.P. (municipal landfill) and 4-5 times higher than levels found in children living in San Luis Potosi, S.L.P. (urban area), in Chihuahua, Chih. (urban area), and San Juan Tilapa, Edo. Mex. (municipal landfills). Results cannot be generalized since the communities selected are not representative of the Mexican population. However, they do indicate that Mexican children are exposed to PBDEs.