An evaluation of the sexual differences in the accumulation of organochlorine compounds in children at birth and at the age of 4 years

Exploring the influence of PCB exposure on neonatal birth outcomes and neurobehavioral development after 15 years of prohibition

Despite polychlorinated biphenyls (PCBs) have been banned in Taiwan for fifteen years, epidemiological studies indicated that prenatal PCB exposure may still affect newborns and their birth outcomes. The study aimed to investigate the association between PCB concentrations in umbilical cord blood and infants' birth outcomes and neurodevelopment. We recruited 100 pairs of mothers and infants, residing in Changhua and Yunlin countries in Taiwan from 2014 to 2016. Maternal questionnaire surveys conducted to collect demographic data, and the Chinese version of the Neonatal Neurobehavioral Assessment Scale was used to assess the development of their neurological behavior in newborns within one to two weeks after birth. Additionally, the Infant Temperament Questionnaire was used to evaluate newborns' responses to stimuli. The measured levels of 23 PCB congeners were analyzed using gas chromatography-electron capture negative ionization quadrupole mass spectrometry (GC-NICI-qMS). Multiple regression explored correlations between prenatal PCB exposure and neonatal birth outcomes, neurobehavioral, and temperament. Additionally, we used the Weighted Quantile Sum (WQS) regression model analysis to identify the major contributing congener. The results revealed that 9 PCB congeners were commonly found in the study participants, specifically PCB138, PCB153, PCB180, PCB156, PCB170, PCB177, PCB187, PCB194, and PCB201. The top three PCBs congeners by levels were PCB138, PCB153, and PCB180 (17.28 ± 16.84, 11.50 ± 15.12, 8.09 ± 14.10 pg/g wet weight, respectively). The decrease in birth weight and head circumference in newborns were each associated with 7 different PCB congeners, with 6 of them being correlated with both, including PCB153, PCB156, PCB177, PCB180, PCB187, and PCB194. Specifically, PCB153 was associated with delayed neurobehavioral development in newborns. Exposure to PCB153, PCB177, and PCB180 influenced the temperament development of newborns. The WQS results indicated that PCB156 and PCB177 were the major contributors to decreased birth weight and head circumference. In conclusion, despite the prohibition of PCB usage, prenatal exposure to PCBs may still affect neonatal health. It is recommended that Taiwan should monitor local newborns' long-term PCB exposure and track potential adverse health effects in their future development.

A comparative monitoring of maternal and cord serum polychlorinated biphenyls levels from Iranian pregnant women between industrial and urban areas

The aim of this study was to compare maternal and fetal exposure to PCBs in pregnant women from a petrochemical and gas area (PGA) and an urban area (UA), by the analyses of serum samples from mother (MS) and cord (CS). After liquid-liquid extracting, samples were analyzed for 12 PCBs congeners by gas chromatography mass spectrometer. Adjusted multiple linear regression models showed the mean levels (μg/L) of total PCBs in the MS and CS samples from the PGA (1.70 ± 0.81 and 1.19 ± 0.43) were significantly higher than those from UA (1.64 ± 0.75 and 1.07 ± 0.38). PCB 44 was predominant in both MS and CS serum samples, and in both PGA (0.80 ± 0.70 and 0.76 ± 0.67) and UA (0.79 ± 0.39 and 0.67 ± 0.34). A negative correlation was found for PCB 52 as one-unit increase in the cord serum levels was associated with 0.024 g decrease in newborn weight. Similarly, one-unit increase in the maternal serum PCB 18 concentrations were associated with 0.09 and 0.086 cm decrease in newborn height and head circumference. The serum levels of PCB 18 and 52 in the mothers who consumed meat and milk at least 1 meal/week were higher than these who consumed meat and milk never or less than 1 meal/month. The findings in this study indicated that higher maternal exposure to PCBs, as result of living in an industrialized area, leads to higher PCBs accumulation in cord blood, which consequently passes to the developing fetus. These events may cause harmful effects on both them in-utero and afterbirth growth and development.

Serum concentrations of persistent organic pollutants mixture during pregnancy and anogenital distance in 8-year-old children from the INMA-Asturias cohort

BACKGROUND

During pregnancy, women are commonly exposed to several endocrine-disrupting chemicals, including persistent organic pollutants (POPs). These compounds can transfer to the fetus through the placenta. Prenatal POP exposure is related to altered fetal genital and reproductive tract development. However, the relationship between exposure to POP mixtures and anogenital distance (AGD) is poorly investigated. This study investigated the association between prenatal exposure to POP mixtures and AGD in 8-year-old children.

METHODS

Data were collected from the INMA-Asturias cohort. Maternal serum POP concentrations were measured during the first trimester of pregnancy. Anoscrotal distance (AGD_AS) and anopenile distance (AGD_AP) in males and anofourchetal distance (AGD_AF) and anoclitoral distance (AGD_AC) in females were recorded in 362 8-years-olds. Conventional linear regression, and the novel weighted quantile sum regression (WQSR) and Bayesian kernel machine regression (BKMR) models were applied to assess the relationships between AGD and POPs exposure stratified by sex.

RESULTS

Among males, in the linear regression, b-hexachlorocyclohexane, PCB138, PCB153, and PCB180 were inversely associated with the anogenital index (AGI)_AS (-0.06 mm/kg (95% confidence interval [CI]: -0.11, -0.02), -0.07 mm/kg (95% CI: -0.14, -0.01), -0.07 mm/kg (95% CI: -0.13, -0.01), and -0.08 mm/kg (95% CI: -0.14, -0.02), respectively). Among females, polybrominated diphenyl ether (PBDE)47 and PBDE154 were positively associated with increased AGI_AF (0.02 mm/kg (95% CI: 0.00, 0.03) and 0.09 mm/kg (95% CI: 0.01, 0.17), respectively). BKMR confirmed these associations. WQSR found a negative combined effect of the POP mixture on AGD, and PCB138, PCB153, and PCB180 (weighted 0.18, 0.13, and 0.09, respectively) were identified as the most impacting chemicals. In females, WQSR found a positive combined effect and determined PBDE47 (weighted 0.35) as the most impacting.

CONCLUSIONS

Maternal exposure to a POP mixture was negatively associated with AGD in male children and positively associated with AGD in female children, thus providing evidence of the adverse effects of POPs on genital development.

Differential Bioaccumulation Patterns of α, β-Hexachlorobenzene and Dicofol in Adipose Tissue from the GraMo Cohort (Southern Spain)

To identify bioaccumulation patterns of α-, β- hexachlorocyclohexane (HCH) and dicofol in relation to sociodemographic, dietary, and lifestyle factors, adipose tissue samples of 387 subjects from GraMo cohort in Southern Spain were analyzed. Potential predictors of these organochlorine pesticides (OCP) levels were collected by face-to-face interviews and assessed by multivariable linear and logistic regression. OCPs were detected in 84.2% (β-HCH), 21.7% (α-HCH), and 19.6% (dicofol) of the population. β-HCH levels were positively related to age, body mass index (BMI), mother's occupation in agriculture during pregnancy, living in Poniente and Alpujarras, white fish, milk and water consumption, and negatively related to being male, living near to an agricultural area, working ≥10 years in agriculture, and beer consumption. Detectable α-HCH levels were positively related to age, BMI, milk consumption, mother's occupation in agriculture during pregnancy, and negatively with residence in Poniente and Alpujarras, Granada city, and Granada Metropolitan Area. Residence near to an agricultural area, smoking habit, white fish and water consumption, and living in Poniente and Alpujarras, Granada city and Granada Metropolitan Area were negatively associated with detectable dicofol levels. Our study revealed different bioaccumulation patterns of α, β-HCH and dicofol, probably due to their dissimilar period of use, and emphasize the need for assessing the exposure to frequently overlooked pollutants.

Prenatal exposure to persistent organic pollutants and markers of obesity and cardiometabolic risk in Spanish adolescents

BACKGROUND

Prenatal exposure to persistent organic pollutants (POPs) has been linked to cardiometabolic (CM) risk factors in childhood, but there are no studies evaluating the persistence of these associations into adolescence, a period of relevant changes in endocrine-dependent organ systems and rapid increases in lean and fat mass. We examined the associations of prenatal POP exposures with body mass index (BMI) from age 4 to 18 years, and with other CM risk markers in adolescence.

METHODS

We analysed 379 children from the Spanish INMA-Menorca birth cohort study with measured cord blood POP concentrations. We calculated BMI z-scores at ages 4, 6, 11, 14 and 18 years using the WHO growth reference. Body fat % was measured at 11 and 18 years and waist-to-height ratio (WHtR) and blood pressure (BP) at 11, 14 and 18 years. We measured CM biomarkers in fasting blood collected at age 14 years and calculated a CM-risk score as the sum of the sex-, and age-specific z-scores for waist circumference, mean arterial BP, homeostatic model assessment of insulin resistance, fasting blood triglycerides, and high-density lipoprotein cholesterol (HDL-C) (n = 217). Generalised estimating equations and multivariate linear regression models assessed the associations with repeated and single time-point measures, respectively.

RESULTS

Hexachlorobenzene (HCB) exposure in the third tertile, compared to the first tertile, was associated with higher BMI (β = 0.24; 95% CI: 0.01, 0.47) and WHtR z-score (β = 0.27; 95% CI: 0.04, 0.51). A continuous increase in HCB was associated with an elevated body fat % (β per 10-fold increase = 4.21; 95% CI: 0.51, 7.92), systolic BP (β = 0.32; 95% CI: 0.02, 0.64) and diastolic BP z-score (β = 0.32; 95% CI: 0.02, 0.62) across all ages, and with higher CM-risk score (β = 1.59; 95% CI: 0.02, 3.18) and lipid biomarkers (total cholesterol, triglycerides and low-density lipoprotein cholesterol (LDL-C)) at 14 years. Dichlorodiphenyltrichloroethane (p,p'-DDT) exposure was non-monotonically associated with BMI and systolic BP. p,p'-DDE and Σ-polychlorinated biphenyls (PCBs) (sum of congeners 118, 138, 153, 180) were not associated with adiposity or BP. p,p'-DDT exposure was associated with an increased CM-risk score, and ΣPCBs concentrations with LDL-C in all adolescents and with total cholesterol only in girls (p-sex interaction = 0.05).

CONCLUSION

This first longitudinal study from 4 to 18 years suggests that the previously reported POP associations with child BMI persist later in adolescence and that prenatal POP exposures are associated with major risk factors for adult CM syndrome.

Perception and Demands of Pregnant and Breastfeeding Women Regarding Their Role as Participants in Environmental Research Studies

A significant proportion of scientific studies consider pregnant and breastfeeding women as vulnerable subjects. The objective of this study was to analyse the perception of pregnant and breastfeeding women regarding their participation in environmental research studies. Our work is a descriptive and interpretative observational study that has been developed under the qualitative research paradigm following a phenomenological and ethnographic perspective. The study involved 173 women selected intentionally in two Spanish autonomous communities. To obtain the primary data, we relied upon 111 interviews, four focused ethnographies and eight focus groups. The data encoding and analysis was carried out with the help of NVivo 12 software (QSR International, Boston, MA, USA). We evidenced the need of pregnant and breastfeeding women for more detailed and accurate information on the risk of environmental pollutant exposure during their crucial life stage. In addition, these women claimed for a more participatory role in research studies. Pregnant and breastfeeding women in Spain ask for greater interaction with researchers and propose a dialogical relationship between valid partners. We conclude that our pregnant and breastfeeding women claim more research focused on their collective, as well as clearer, more accessible and structured information on the risks of exposure to environmental contaminants. In addition, they do not want to simply be informants; rather, they ask to be active and empowered members by providing their opinions and arguments throughout the research process.

Maternal and cord serum levels of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) among Lebanese pregnant women and predictors of exposure

In this study, the six indicator non-dioxin-like polychlorinated biphenyls NDL-PCBs (PCB28, PCB52, PCB101, PCB138, PCB153, PCB180), as well as four organochlorine pesticides (OCPs), hexachlorobenzene (HCB), β-hexachlorocyclohexane (β-HCH), dichlorodiphenyltrichloroethane (DDT), and dichlorodiphenyldichlorethylene (DDE) were measured in 98 maternal and 49 cord sera samples of a group of Lebanese women who gave birth in three hospitals in Greater Beirut, between March and July 2018. Results showed that the levels of these persistent organic pollutants (POPs) in maternal serum were below critical limits as well as those in other countries (Tunisia, France, Portugal, Spain, Poland, Greenland, Canada, Brazil, and China). The ratios of cord serum concentrations to maternal serum concentrations of analyzed POPs were higher than 1. PCB maternal serum concentrations were found to be linked to illegal incineration (OR = 5.78; p = 0.004) as well as eggs (OR = 4.68; p = 0.027) and fruits and vegetables consumption (OR = 3.92; p = 0.016). OCP concentrations were linked to red meat and cold cuts intake (OR = 3.67-4.59; p = 0.001-0.004). While PCB levels were not correlated to newborns anthropometric measurements, OCP levels in cord serum were found to be positively linked to the birth length of newborns (p = 0.014-0.027).

Association between pre/perinatal exposure to POPs and children's anogenital distance at age 4 years: A study from the INMA-Asturias cohort

BACKGROUND

Prenatal exposure to endocrine-disrupting chemicals may impair genital development and alter reproductive tract anatomy. Anogenital distance (AGD) is a useful biomarker of exposure to chemicals that act as endocrine disruptors. We evaluated associations between prenatal and perinatal exposure to several persistent organic pollutants (POPs) and AGD in 4-year-old children.

METHODS

Data were drawn from the INMA-Asturias cohort. Pediatricians measured the anofourchetal distance in female children and anoscrotal distance in male children. The anogenital index (AGI) was defined as the AGD divided by the child's weight at age of examination. We measured the levels of two hexachlorocyclohexane isomers, hexachlorobenzene, dichlorodiphenyltrichloroethane (DDT) and its metabolites, six polychlorinated biphenyl (PCB) congeners, and six polybrominated diphenyl ether (PBDE) congeners in maternal serum at 12 gestational weeks (n = 155) and in cord blood serum (n = 229). Anthropometric and parental sociodemographic variables were collected via face-to-face interviews. Linear regression models were used to evaluate the relationship between exposure to POPs and AGI, adjusted for confounders and stratified by sex.

RESULTS

In male children, we found inverse associations between AGI and maternal concentrations of PCB-138 (ß = -0.041, 95% confidence interval [CI]: -0.074, -0.008, second tertile), PCB-153 (ß = -0.052, 95% CI: -0.085, -0.020, second tertile), PCB-180 ß = -0.065, 95% CI: -0.096, -0.035, second tertile; ß = -0.042, 95% CI: -0.073, -0.011, third tertile), PBDE-209 (ß = -0.031, 95% CI: -0.058, -0.006), cord serum concentrations of PCB-153 (ß = -0.029, 95% CI: -0.059, -0.000, second tertile; ß = -0.047, 95% CI: -0.085, -0.008, third tertile), and PCB-180 (ß = -0.041, 95% CI: -0.078, -0.005, third tertile). In female children, AGI was positively associated with maternal serum concentrations of PCB-101 (ß = 0.039, 95% CI: 0.002, 0.076, second tertile), and higher cord serum levels of 4,4'-DDT (ß = 0.032, 95% CI: 0.003, 0.061, third tertile) and 4,4'-DDE (ß = 0.040, 95% CI: 0.011, 0.069, third tertile).

CONCLUSIONS

Our findings provide evidence of associations between specific POPs and AGI in boys and girls aged 4 years, and suggest that pre/perinatal exposure to POPs has a feminizing effect in males and a masculinizing effect in females.

Changes of organochlorine compound concentrations in maternal serum during pregnancy and comparison to serum cord blood composition

The concentrations of organochlorine compounds (OCs), including pentachlorobenzene, hexachlorobenzene (HCB), hexachlorocyclohexanes (α-, β-, γ- and δ-HCH), polychlorobiphenyls (PCBs 28, 52, 101, 118, 138, 153 and 180), DDT and metabolites, were measured in maternal serum samples collected at the first trimester of pregnancy, at delivery and in umbilical cord from a cohort of mother-newborn pairs from Tarragona (Spain) (n = 50), representing general population of a Mediterranean area from Southern Europe. The observed concentrations were generally low in comparison with previous studies in other world areas. Higher OC concentrations were observed in the maternal serum collected at delivery than in the first trimester and the cord blood concentrations were lower than the maternal levels. These results show for the first time a small but statistically significant increase in maternal venous concentration of OCs between the first trimester and delivery when measured in ng/ml. HCB, β-HCH and the PCB congeners in cord blood were significantly correlated with the concentrations of these compounds in maternal venous blood and the coefficients were stronger for the samples collected at delivery which was consistent with OC transfer from mother to foetus. In the case of DDT compounds, only 4,4'-DDT showed maternal-cord blood correlation which documented the low metabolic capacity of newborns for OC transformation, e.g. DDT into DDE. Maternal age was the most significant driver of the observed maternal venous OC concentrations in both periods, older ages involving higher concentrations. Higher body mass index was only significantly correlated with higher 4,4'-DDE concentrations in maternal venous blood and cord blood. In some cases, social class and education level were significantly correlated with OC concentrations, e.g. 4,4'-DDE in maternal venous blood from the first trimester and cord blood and PCB153 in maternal venous blood at delivery. In these cases, highest concentrations were found in the women with highest education level and most affluent social class. Comparison of the maternal OC concentrations of this cohort with those observed in 2002 in population of the same geographic area and age range shows decreases between two and ten times over this fourteen-year period.

Adverse effects of hexaclorobenzene exposure in children and adolescents

BACKGROUND

Hexachlorobenzene (HCB: C₆Cl₆) is a persistent, bioaccumulative chemical formerly used worldwide in pesticide mixtures but also produced as a by-product in the chemical and metallurgical industry. Despite current international restrictions in the use and production of HCB, the majority of the general population still show detectable levels of HCB, which raises concerns on the potential health implications of the exposure.

OBJECTIVE

To compile and synthesize the available scientific evidence regarding the adverse effects of exposure to HCB in children and adolescents.

METHODS

A review of the literature focused on the adverse effects of HCB exposure in children. Eligible studies were systematically screened from searches in Medline, Scopus and Ebsco-host databases. A total of 62 studies were finally included.

RESULTS AND DISCUSSION

In our search we found evidences of potential health effects linked to HCB exposure at different levels (e.g. neurotoxic, nephrotoxic, immunotoxic, hepatotoxic and toxicogenomic), although the conclusions are still contradictory. Further prospective research is needed, considering the special vulnerability of children and adolescent population as well as the ubiquity of the exposure.

Prenatal Exposure to Persistent Organic Pollutants and Anogenital Distance in Children at 18 Months

BACKGROUND

Anogenital distance (AGD) is a measure of in utero exposure to hormonally active agents. The aim of the present study was to evaluate the association between prenatal exposure to persistent organic pollutants (POPs) and AGD.

METHODS

POP levels were measured in pregnant women, and the AGD was recorded in 43 offspring at 18 months. We used linear regression models to analyze the association between maternal POP exposure and offspring AGD. We defined the anogenital index (AGI) as AGD divided by weight at 18 months (AGI = AGD / weight at 18 months [mm/kg]) and included this variable in the regression models.

RESULTS

AGI measure was 2.35 (0.61) and 1.38 (0.45) in males and females, respectively. AGI was inversely associated with lipid-adjusted concentrations of PBDE-99 (β = -0.28, 95% confidence interval [CI]: -0.51, -0.04) and PBDE-153 (β = -0.61, 95% CI: -1.11, -0.11) in males. We did not find any statistically significant relationship between any POPs and AGI in females.

CONCLUSIONS

Environmental exposure to POPs may affect genital development and result in reproductive tract alterations with potentially relevant health consequences in maturity.

Levels of dioxin-like PCBs in low-volume serum samples of male patients attending fertility clinics

An accurate and easy method for the extraction, cleanup, and HRGC-HRMS analysis of dioxin-like PCBs (DL-PCBs) in low-volume serum samples (1 mL) was developed. Serum samples were extracted several times using n-hexane and purified by acid washing. Recovery rates of labeled congeners ranged from 70 to 110% and the limits of detection were below 1 pg/g on lipid basis. Although human studies are limited and contradictory, several studies have shown that DL-PCBs can have adverse effects on the male reproductive system. In this way, the present method was applied to 21 serum samples of male patients attending fertility clinics. The total levels obtained for the patients ranged from 6.90 to 84.1 pg WHO-TEQ/g lipid, with a mean value of 20.3 pg WHO-TEQ/g lipid. The predominant PCBs (the sum of PCB 118, 156, and 105) contributed 67% to the mean concentration of total DL-PCBs in the samples analyzed.

Serum concentrations of PCBs and OCPs among prepubertal Korean children

Although children are more vulnerable than adults to environmental hazards, due to their physiological and behavioral characteristics, few studies have assessed their internal exposure to persistent organic pollutants (POPs). The objective of this study was to determine the serum levels of certain polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) among pre-pubertal children in Korea and examine their variation with age and gender. We analyzed a total of 51 POPs in 214 children (age range, 7-9 years), using data from the Ewha Birth and Growth Cohort Study. To examine change over time, POP concentrations were measured at both 7 and 9 years of age in a sub-cohort of 26 children. The median and interquartile range (IQR, 25th to 75th percentiles) data for the sum of PCB congeners was 26.44 ng/g lipid (18.27-37.63 ng/g lipid). The median (IQR) concentration for the sum of OCPs was 74.82 ng/g lipid (51.11-112.45 ng/g lipid). Our results showed significant increases in serum concentrations of total PCBs with age (p = 0.0001), no gender dependence of total PCBs (p = 0.38) and total OCPs (p = 0.12), and strong correlations between individual POPs. Childhood exposure to POPs was relatively low compared to other studies carried out in different countries. However, even though the use of POPs has been banned since 2001, our results indicated that children in the general population are still exposed to various POPs. Because long-term, low-level exposure to POPs in the general population remains a concern for human health, future research should examine major routes of exposure and identification of risk factors.

Influence of socio-demographic and diet determinants on the levels of mercury in preschool children from a Mediterranean island

Mercury levels measured in 302 hair samples of 4 year-old children from Menorca (western Mediterranean Sea) are reported. Their concentrations, arithmetic mean 1.4 μg/g, ranging between 0.040 μg/g and 10 μg/g, were higher than in other children inland populations but lower than in previously studied island cohorts, e.g. Faroe, Madeira and Seychelles. 20% of the samples were above the WHO recommended values. Higher concentrations in females than males were observed. Frequent consumption of fish and other seafood were significantly related to the observed mercury concentrations. Oily fish was the main source of this pollutant but shellfish and squid consumption were also associated with high mercury concentrations. Maternal smoking, occupational status or previous siblings were also found to significantly influence the levels of this pollutant. McCarthy Scales of Children's Abilities used to assess children's motor and cognitive abilities did not show association with mercury concentrations at 4 years of age.

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

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

Prenatal exposure to organochlorine compounds and neuropsychological development up to two years of life

Polychlorinated biphenyls (PCB), hexachlorobenzene (HCB), and dichlorodiphenyl dichloroethylene (pp'DDE) are persistent, bioaccumulative, and toxic environmental pollutants with potential neurotoxic effects. Despite a growing body of studies investigating the health effects associated with these compounds, their specific effects on early neuropsychological development remain unclear. We investigated such neuropsychological effects in a population-based birth cohort based in three regions in Spain (Sabadell, Gipuzkoa, and Valencia) derived from the INMA [Environment and Childhood] Project. The main analyses in this report were based on 1391 mother-child pairs with complete information on maternal levels of organochlorine compounds and child neuropsychological assessment (Bayley Scales of Infant Development) at age 14 months. We found that prenatal PCB exposure, particularly to congeners 138 and 153, resulted in impairment of psychomotor development (coefficient=-1.24, 95% confidence interval=-2.41, -0.07), but found no evidence for effects on cognitive development. Prenatal exposure to pp'DDE or HCB was not associated with early neuropsychological development. The negative effects of exposure to PCBs on early psychomotor development suggest that the potential neurotoxic effects of these compounds may be evident even at low doses.

Longitudinal association between early life socio-environmental factors and attention function at the age 11 years

Prenatal and early-life exposures can affect the course of children's neuropsychological development well into pre-adolescence, given the vulnerability of the developing brain. However, it is unknown which socio-environmental factors at early childhood can influence specific cognitive processes like attention at a later age. In this study, we aim to determine social and environmental exposures in early childhood that may be associated with attention function of 11-year-olds. We measured attention function using the continuous performance test-II (CPT-II) on 393 11-year old children from the Menorca's birth-cohort within the INMA-project (Spain), and pre-selected a list of socio-environmental observations taken when they were up to 4 years of age. We found that earlier socio-environmental characteristics, such as parental social class, educational level and maternal mental health are associated with later inattentive and impulsive symptomatology through a higher rate of omission and commission errors. In addition, omission errors were higher in children with atopy and lower in those whose mothers took dietary supplementation with folic acid and vitamins during pregnancy. Breastfeeding played a protective role against commission errors, while higher DDE and PCBs levels at age 4 were associated with slow speed response. Our findings suggest that a number of life socio-environmental factors during prenatal life and early childhood, such as socio-demographic characteristics, breastfeeding, maternal nutritional supplementation with folic acid and vitamins and exposure to some organochlorine compounds may influence inattentive and hyperactive/impulsive symptomatology during pre-adolescence.

Distribution of blood concentrations of persistent organic pollutants in a representative sample of the population of Barcelona in 2006, and comparison with levels in 2002

INTRODUCTION

POP biomonitoring programs are useful for exposure assessment, to analyze patterns, and to evaluate policies. However, population-representative surveys are scarce and heterogeneous. Reports on time trends in representative samples using the same methods are rare.

OBJECTIVES

To analyze the distribution of serum concentrations of 19 POPs in the general population of Barcelona city in 2006, and to compare it with the distribution in 2002.

METHODS

231 participants in the Barcelona Health Survey were interviewed face-to-face, gave blood, and underwent a physical exam. Density plots ("POP Geoffrey Rose curves") were used to represent the full population distribution of each compound.

RESULTS

Eight POPs were each detected in >80% of the study subjects: p,p'-DDT, p,p'-DDE, PCB congeners 118, 138, 153 and 180, HCB and β-HCH. The minimum number of POPs detected in one person was 5, and 72% of the population accumulated ≥ 10 compounds. p,p'-DDE and HCB showed the highest concentrations (median=219 and 109 ng/g lipid, respectively). Concentrations decreased by 34-56% from 2002 to 2006. The decrease was similar in women and men, and in all age groups/birth cohorts. It was larger with increasing BMI; for p,p'-DDT, HCB and β-HCH the decrease in obese individuals was 31-44 percentage points larger than in subjects with normal weight. The distribution of POP concentrations was always switched towards higher values in women than men. POP levels also differed significantly by age, body mass index, weight gain, birth place and social class, but not by parity and breastfeeding. The two younger cohorts had a higher DDT/DDE ratio than the oldest cohort.

CONCLUSION

Although human POP contamination remains common in the city of Barcelona, concentrations decreased significantly in 4years. Our approach suggests innovative ways to conceive, analyze and present results for other monitoring programs.

Prenatal concentrations of polychlorinated biphenyls, DDE, and DDT and overweight in children: a prospective birth cohort study

BACKGROUND

Recent experimental evidence suggests that prenatal exposure to endocrine-disrupting chemicals (EDCs) may increase postnatal obesity risk and that these effects may be sex or diet dependent.

OBJECTIVES

We explored whether prenatal organochlorine compound (OC) concentrations [polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (DDE), and dichlorodiphenyltrichloroethane (DDT)] were associated with overweight at 6.5 years of age and whether child sex or fat intakes modified these associations.

METHODS

We studied 344 children from a Spanish birth cohort established in 1997-1998. Overweight at 6.5 years was defined as a body mass index (BMI) z-score ≥ 85th percentile of the World Health Organization reference. Cord blood OC concentrations were measured and treated as categorical variables (tertiles). Children's diet was assessed by food frequency questionnaire. Relative risks (RRs) were estimated using generalized linear models.

RESULTS

After multivariable adjustment, we found an increased RR of overweight in the third tertile of PCB exposure [RR = 1.70; 95% confidence interval (CI): 1.09, 2.64] and the second tertile of DDE exposure (RR = 1.67; 95% CI: 1.10, 2.55), but no association with DDT exposure in the population overall. Associations between overweight and PCB and DDE concentrations were strongest in girls (p-interaction between 0.01 and 0.28); DDT was associated with overweight only in boys. For DDT we observed stronger associations in children with fat intakes at or above compared with below the median, but this interaction was not significant (p-interaction > 0.05).

CONCLUSIONS

This study suggests that prenatal OC exposures may be associated with overweight in children and that sex and high-fat intake may influence susceptibility.

Assessment of exposure to PCB 153 from breast feeding and normal food intake in individual children using a system approach model

Investigators have typically relied on a single or few discrete time points as measures of polychlorinated biphenyl (PCB) body burden, however health effects are more likely to be the result of integrative exposure in time, optionally expressed as an area under the time curve (AUC) of PCB serum concentration. Using data from a subgroup of 93 infants from a birth cohort in eastern Slovakia-a region highly polluted by PCBs-we fit a system type model, customized to our longitudinal measures of serum PCB concentrations in cord, 6, 16, and 45 month blood specimens. The most abundant congener, PCB 153, was chosen for modeling purposes. In addition to currently used methods of exposure assessment, our approach estimates a concentration time profile for each subject, taking into account mean residence time of PCB 153 molecules in the body, duration of breast feeding, hypothetical PCB 153 concentration in steady-state without breast feeding and alternately without normal food intake. Hypothetical PCB 153 concentration in steady-state without normal food intake correlates with AUC (r=0.84, p<0.001) as well as with duration of breast feeding (r=0.64, p<0.001). It makes possible to determine each subject's exposure profile expressed as AUC of PCBs serum concentration with a minimum model parameters. PCB body burden in most infants was strongly associated with duration of breast feeding in most, but not all children, was apparent from model output.

Half-lives of serum PCB congener concentrations in environmentally exposed early adolescents

The aim was to determine half-life of six most abundant PCB congeners in the body of early adolescents. In 304 environmentally exposed children, PCB serum concentration was determined at the age of 8 and 12years. Half-life was determined for each child assuming exponential decrease or for the whole cohort using multiple regression. Results obtained by both approaches were in agreement. PCB reuptakes corrupting half-life estimates for each child and each congener were evaluated. If one of the serum PCB concentration values fell below the level of detection (LOD) the pair was excluded and if PCB half-life value exceeded the arbitrary value of 30years. The following median half-lives in years 4.46, 10.59, 9.7, 4.7, 9.1 and 9.8 were obtained for PCB congeners 118, 138(+163), 153, 156(+171), 170 and 180, respectively. The elimination half-life values were not systematically related to PCB serum concentration at any examination age. Between half-life values, percentage of children with significant reuptakes and PCB congener abundance in serum were found significant associations.