Monika Kasper-Sonnenberg

Levels of phthalate metabolites in urine among mother–child-pairs – Results from the Duisburg birth cohort study, Germany

Phthalates are used ubiquitously and human exposure is widespread. Some phthalates are anti-androgens and have to be regarded as reproductive and developmental toxicants. In the Duisburg birth cohort study we examine the associations between hormonally active environmental agents and child development. Here we report the concentrations of 21 primary and secondary phthalate metabolites from seven low molecular weight (LMW) phthalates (DMP, DEP, BBzP, DiBP, DnBP, DCHP, DnPeP) and five high-molecular weight (HMW) phthalates (DEHP, DiNP, DiDP, DPHP, DnOP) in 208 urine samples from 104 mothers and their school-aged children. Analysis was performed by multidimensional liquid chromatography coupled to tandem mass spectrometry (LC/LC-MS/MS), using internal isotope-labeled standards. In both children and mothers, 18 out of 21 phthalate metabolites were detected above the limits of quantification (between 0.2 and 1.0 μg/l) in nearly all urine samples. Among the LMW phthalates, the excretion level (geometric mean) of the ΣDiBP metabolites was most prominent in children (103.9 μg/l), followed by ΣDnBP (56.5 μg/l), and MEP (39.1 μg/l). In mothers ΣDiBP (66.6 μg/l) was highest, followed by MEP (50.5 μg/l), and ΣDnBP (36.0 μg/l). Among the HMW phthalates, ΣDEHP was highest in children and mothers (55.7/28.9 μg/l). Compared to reference values derived from the German Human Biomonitoring Commission, childrens metabolite concentrations were within background levels, whereas for mothers considerably higher exposure to the LMW phthalates DnBP and DiBP, and the HMW phthalate DEHP was detected (MiBP: 10.7%; MnBP: 11.7%; ΣDEHP: 23.3% of the samples were above the reference values). The LMW metabolites from DMP, DiBP, and DnBP, and the HMW metabolites from DEHP and DiNP were correlated between the mothers and children, probably indicating shared exposure in the immediate surrounding environment. Children showed higher excretion levels for most of the secondary metabolites than mothers, confirming previous findings on higher oxidized metabolite levels in children. The LMW metabolites ΣDiBP, ΣDnBP, and MMP, and the HMW metabolites ΣDEHP were negatively associated with childrens age. The LMW metabolites ΣDiBP, ΣDnBP, and MBzP were inversely associated with body mass index of the children. The LMW ΣDiBP metabolites revealed a significant association with nicotine metabolites in urine from both children and mothers. Further analyses are ongoing to study long-term phthalate exposure and the associations with puberty outcome in these children.

Prenatal and postnatal exposure to persistent organic pollutants and Infant growth: A pooled analysis of seven european birth cohorts

Background Infant exposure to persistent organic pollutants (POPs) may contribute to obesity. However, many studies so far have been small, focused on transplacental exposure, used an inappropriate measure to assess postnatal exposure through breastfeeding if any, or did not discern between prenatal and postnatal effects. Objectives We investigated prenatal and postnatal exposure to POPs and infant growth (a predictor of obesity). Methods We pooled data from seven European birth cohorts with biomarker concentrations of polychlorinated biphenyl 153 (PCB-153) (n = 2,487), and p,p´-dichlorodiphenyldichloroethylene (p,p´-DDE) (n = 1,864), estimating prenatal and postnatal POPs exposure using a validated pharmacokinetic model. Growth was change in weight-for-age z-score between birth and 24 months. Per compound, multilevel models were fitted with either POPs total exposure from conception to 24 months or prenatal or postnatal exposure. Results We found a significant increase in growth associated with p,p´-DDE, seemingly due to prenatal exposure (per interquartile increase in exposure, adjusted β = 0.12; 95% CI: 0.03, 0.22). Due to heterogeneity across cohorts, this estimate cannot be considered precise, but does indicate that an association with infant growth is present on average. In contrast, a significant decrease in growth was associated with postnatal PCB-153 exposure (β = –0.10; 95% CI: –0.19, –0.01). Conclusion To our knowledge, this is the largest study to date of POPs exposure and infant growth, and it contains state-of-the-art exposure modeling. Prenatal p,p´-DDE was associated with increased infant growth, and postnatal PCB-153 with decreased growth at European exposure levels. Citation Iszatt N, Stigum H, Verner MA, White RA, Govarts E, Palkovicova Murinova L, Schoeters G, Trnovec T, Legler J, Pelé F, Botton J, Chevrier C, Wittsiepe J, Ranft U, Vandentorren S, Kasper-Sonnenberg M, Klümper C, Weisglas-Kuperus N, Polder A, Eggesbø M, OBELIX. 2015. Prenatal and postnatal exposure to persistent organic pollutants and infant growth: a pooled analysis of seven European birth cohorts. Environ Health Perspect 123:730–736; http://dx.doi.org/10.1289/ehp.1308005

DETERMINATION OF BISPHENOL A IN URINE FROM MOTHER-CHILD PAIRS—RESULTS FROM THE DUISBURG BIRTH COHORT STUDY, GERMANY

Bisphenol A (BPA) may alter endocrine functions, and human exposure is widespread. In the Duisburg birth cohort study the influence of several contaminants was examined on the neuropsychological and pubertal development of children. This study reports the biomonitoring results on BPA within the 6-yr follow-up study (children´s age 6–8 yr). Total BPA and free (unconjugated) BPA concentrations in 208 urine samples of 104 mother–child pairs were measured. For quality control, total BPA was analyzed by two independent laboratories. BPA was detected in all urine samples, while free BPA was observed above the limit of quantification (LOQ) in only 33 samples. Total BPA concentrations were significantly associated between the two laboratories. BPA concentrations (median; range) tended to be higher in children than in mothers but the difference was not significant. Total BPA levels in children and mothers correlated at low levels but significantly to each other. Multivariate linear regression analysis revealed positive associations between creatinine and the BPA concentrations and a negative association with German nationality (mothers only). Evidence indicates that BPA exposure is omnipresent but levels in mother–child pairs are low. Only small amounts (less than 16%) were detectable as free (unconjugated) BPA. Analytical reliability is high even at such low levels, provided that external contamination is minimized.

The influence of low level pre- and perinatal exposure to PCDD/Fs, PCBs, and lead on attention performance and attention-related behavior among German school-aged children: results from the Duisburg Birth Cohort Study.

BACKGROUND Prenatal exposure to polychlorinated biphenyls (PCBs) and lead are thought to be risk factors for attention-deficit hyperactivity disorder (ADHD), whereas the prenatal influence of polychlorinated dibenzo-p-dioxins and -furans (PCDD/Fs) on attention performance has been less studied. OBJECTIVES Within the Duisburg Birth Cohort Study, we investigated low-level exposure to these compounds in relation to childrens attention. METHODS We measured blood levels of PCDD/Fs, PCBs and lead from pregnant mothers (32(nd) week of pregnancy) and PCDD/Fs and PCBs in breast milk (2 weeks after delivery). The attention of school-aged children (N=117) was investigated with a computer-based test battery of attention performance (KITAP) and a parent rating questionnaire of behaviors related to ADHD (FBB-ADHS). Influences of the exposure on attention were analyzed by multiple regression analyses. RESULTS Increasing prenatal PCDD/F and PCB concentrations were significantly (p<0.05) associated with a higher number of omission errors in the subtest Divided Attention (47% and 42%; 95% confidence intervals (95%-CI): 1.08-2.00 and 1.07-1.89, respectively). Prenatal lead concentrations had few significant associations with attention performance (e.g., a 23% higher number of omission errors in the subtest Distractibility; 95%-CI: 1.00-1.51), whereas ADHD-related behavior (questionnaire based) was increased with increasing lead exposure (Overall-ADHD: 9%; 95%-CI: 1.01-1.17). ADHD-related behavior was negatively associated with prenatal PCDD/F or PCB exposures (e.g., for PCB exposure: -10%; 95%-CI: 0.82-0.99). CONCLUSIONS Pre- and perinatal PCDD/F and PCB exposure may have subtle influences on attention performance in healthy children at low environmental levels, while behavior changes are negatively associated. Furthermore, we provide additional evidence for the impact of prenatal lead exposure on attention deficits.

Phthalate metabolites and bisphenol A in urines from German school-aged children: Results of the Duisburg Birth Cohort and Bochum Cohort Studies

Some phthalates and also bisphenol A (BPA) interfere with the human endocrine system and are labelled as reproductive toxicants. Childrens exposure to these contaminants is suspected to be associated with developmental disorders and other health impairments. We provide biomonitoring data on 21 urinary phthalate metabolite and BPA levels in first morning urine of 8-10 year old children. Participants were children born between 1999 and 2002 of the Duisburg birth cohort (8-9 years, N=113) and of the Bochum cohort study (8-10 years, N=352). Additionally, for the Duisburg birth cohort we compare current data of children from Duisburg (8-9 years) with data from 2 years earlier when the children were 6-7 years old. We analyzed influences of important covariates on exposure levels by multiple regression analysis and those from two sampling time points by generalized equation estimation models adjusted for important covariates. Compared to recently published studies the phthalate metabolite and BPA concentrations were within the range of background levels. There were no significant differences between children from Bochum and Duisburg. Comparison between the two Duisburg birth cohort data sets (2007-2008 and 2009-2010) showed significant correlations for most of the phthalate metabolites (r Spearman between 0.25 and 0.51; p ≤ 0.05) but not for BPA (r Spearman=0.162; p=0.143). Most of the phthalate metabolites in the groups of the 6-7 and 8-9 years old Duisburg children were negatively associated with higher age, except for BPA concentrations with nearly constant levels. Exposure levels may be influenced by changes in child specific exposure patterns with age but also by the rapidly changing phthalate market.

Behavioral Sexual Dimorphism in School-Age Children and Early Developmental Exposure to Dioxins and PCBs: A Follow-Up Study of the Duisburg Cohort

Background: Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) are persistent organic pollutants that have been characterized as endocrine-disrupting chemicals (EDCs). Objectives: Within the Duisburg birth cohort study, we studied associations of prenatal exposure to PCDD/Fs and PCBs with parent-reported sexually dimorphic behavior in children. Methods: We measured lipid-based and WHO2005-TEQ (toxic equivalents established in 2005 by the World Health Organization)–standardized PCDD/Fs and PCBs in maternal blood samples and in early breast milk using gas chromatography/high-resolution mass spectrometry. At the child’s age of 6–8 years, parents (mostly mothers) reported sex-typical characteristics, preferred toys, and play activities using the Pre-School Activities Inventory (PSAI), which was used to derive feminine, masculine, and difference (feminine – masculine) scores. We estimated exposure–outcome associations using multivariate linear regression. A total of 91–109 children were included in this follow-up. Results: Mean blood levels of summed WHO2005-TEQ–standardized dioxins (ΣPCDD/Fs) were 14.5 ± 6.4 pg/g blood lipids, and ΣPCBs were 6.9 ± 3.8 pg/g blood lipids, with similar values for milk lipids. Regression analyses revealed some highly significant interactions between sex and exposure—such as for ΣPCBs in milk, pronounced positive (boys: β = 3.24; CI = 1.35, 5.14) or negative (girls: β = –3.59; CI = –1.10, –6.08) associations with reported femininity. Less pronounced and mostly insignificant but consistent associations were found for the masculinity score, positive for boys and negative for girls. Conclusions: Given our results and the findings of previous studies, we conclude that there is sufficient evidence that these EDCs modify behavioral sexual dimorphism in children, presumably by interacting with the hypothalamic–pituitary–gonadal axis. Citation: Winneke G, Ranft U, Wittsiepe J, Kasper-Sonnenberg M, Fürst P, Krämer U, Seitner G, Wilhelm M. 2014. Behavioral sexual dimorphism in school-age children and early developmental exposure to dioxins and PCBs: a follow-up study of the Duisburg Cohort. Environ Health Perspect 122:292–298; http://dx.doi.org/10.1289/ehp.1306533

Influence of Low-Level Prenatal Exposure to PCDD/Fs and PCBs on Empathizing, Systemizing and Autistic Traits: Results from the Duisburg Birth Cohort Study

Background Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) are assumed to act as endocrine disruptor chemicals. Prenatal exposure to these pollutants might influence fetal steroid hormone levels, which are thought to be related to sex-typical development and autistic traits. Objectives We examined associations of prenatal levels of PCDD/Fs and PCBs with autism traits and sex-typical behaviour in childhood. Methods We measured levels of PCDD/Fs and PCBs in maternal blood samples during pregnancy using gas chromatography/high-resolution mass spectrometry. Sex-typical behaviour was assessed at 9 years of age (n = 96) and autistic traits at 10 years of age using the Social Responsiveness Scale (SRS; n = 100). Multiple regression analyses were conducted to estimate the associations between prenatal exposure and outcome variables. Results Blood concentrations (WHO2005-TEq) of ƩPCDD/Fs ranged from 2.93–46.45 pg/g lipid base (median = 12.91 pg/g lipid base) and concentrations of ƩPCBs were in the range of 1.24–25.47 pg/g lipid base (median = 6.85 pg/g lipid base) which is within the range of German background exposure. We found significant negative associations between PCDD/F levels in maternal blood and SRS scores in the whole group (β = -6.66, p < .05), in girls (β = -10.98, p < .05) and, in one SRS subscale, in boys (β = -6.86, p < .05). For PCB levels, associations with one SRS subscale were significant for the whole study group as were associations with two subscales in girls. We did not find significant associations between PCDD/F or PCB levels and sex-typical behaviour for either sex. Conclusions In an earlier part of this study, prenatal exposure to PCDD/Fs and PCBs was found to be associated with lower testosterone levels, therefore, our findings are consistent with the idea that autism spectrum conditions are related to fetal androgen levels. Several possible mechanisms, through which PCDD/Fs and PCBs might influence autistic behaviour, are discussed.

Prenatal Exposure to DDE and PCB 153 and Respiratory Health in Early Childhood A Meta-Analysis

Background: Persistent organic pollutants may affect the immune and respiratory systems, but available evidence is based on small study populations. We studied the association between prenatal exposure to dichlorodiphenyldichloroethylene (DDE) and polychlorinated biphenyl 153 (PCB 153) and children’s respiratory health in European birth cohorts. Methods: We included 4608 mothers and children enrolled in 10 birth cohort studies from 7 European countries. Outcomes were parent-reported bronchitis and wheeze in the first 4 years of life. For each cohort, we performed Poisson regression analyses, modeling occurrences of the outcomes on the estimates of cord-serum concentrations of PCB 153 and DDE as continuous variables (per doubling exposure) and as cohort-specific tertiles. Summary estimates were obtained through random-effects meta-analyses. Results: The risk of bronchitis or wheeze (combined variable) assessed before 18 months of age increased with increasing DDE exposure (relative risk [RR] per doubling exposure = 1.03 [95% confidence interval = 1.00–1.07]). When these outcomes were analyzed separately, associations appeared stronger for bronchitis. We also found an association between increasing PCB 153 exposure and bronchitis in this period (RR per doubling exposure = 1.06 [1.01–1.12]) but not between PCB 153 and wheeze. No associations were found between either DDE or PCB 153 and ever-wheeze assessed after 18 months. Inclusion of both compounds in the models attenuated risk estimates for PCB 153 tertiles of exposure, whereas DDE associations were more robust. Conclusion: This large meta-analysis suggests that prenatal DDE exposure may be associated with respiratory health symptoms in young children (below 18 months), whereas prenatal PCB 153 levels were not associated with such symptoms.

Prenatal and Early Life Exposure to Polychlorinated Dibenzo-p-Dioxins, Dibenzofurans and Biphenyls May Influence Dehydroepiandrosterone Sulfate Levels at Prepubertal Age: Results from the Duisburg Birth Cohort Study

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) and polychlorinated biphenyls (PCB) are postulated to act as endocrine disrupters. In the ongoing Duisburg birth cohort study, started in 2000–2002, influence of persistent organic pollutants (POP) on child development was monitored. For the first time, associations were reported between prenatal and postnatal PCDD/F and PCB exposures and early endocrinological changes concerning adrenarchal development. PCDD/F and PCB concentrations were measured in blood samples taken in wk 32 of pregnancy and in breast milk using gas chromatography and high-resolution mass spectrometry (GC/HRMS). At the age of 6–7 and 8–9 yr, serum samples were collected from 111 children. The samples were assayed for the sex hormones testosterone, estradiol, dehydroepiandrosterone sulfate (DHEA-S), and 17-OH-progesterone (17-OHP) by using an automated chemiluminescence assay system. Analyses of repeated measurements of DHEA-S serum levels were performed by linear regression analysis using generalized estimating equations (GEE). Linear regression analysis showed a positive association between DHEA-S and breast milk levels of PCDD/F and PCB expressed as toxicity equivalents according to toxicity equivalent factors published by the World Health Organization (WHO) in 2005 (WHO2005-TEq) (increase of 29%, geometric mean ratio, GMR: 1.29, 95% CI 1.06–1. 58 per doubling of PCDD/F + PCB WHO2005-TEq levels). Results for the association with the WHO2005-TEq levels in blood of mothers were in the same direction (increase of 15%, GMR 1.15, 95% CI 0.93–1.42 per doubling of PCDD/F + PCB WHO2005-TEq levels), but not significant. Data indicate that PCDD/F and PCB exposure in infancy may influence DHEA-S serum levels in prepubertal children. Increased DHEA-S serum levels are considered to indicate acceleration of the adrenal maturation.

Perfluoroalkyl acids in children and their mothers: Association with drinking water and time trends of inner exposures—Results of the Duisburg birth cohort and Bochum cohort studies

BACKGROUND Perfluoroalkyl acids (PFAAs) are widely distributed in the environment and humans are globally exposed with them. Contaminated drinking water can considerably contribute to the inner exposure levels. OBJECTIVES We report the results of a human biomonitoring study with mother-child pairs living in two German cities, one city with PFAA contaminated drinking water in the sub μg/l-range (Bochum) and the other one without contamination (Duisburg). Furthermore, we studied time trends of exposure levels within the Duisburg cohort study. METHODS We measured seven PFAAs (PFOS, PFOA, PFHxS, PFNA, PFBS, PFDeA, PFDoA) in blood samples by high performance liquid chromatography and tandem mass spectrometry. Samples were taken during pregnancy, from umbilical cord blood (2000-2002), 6-7 years (5th follow-up) and 8-10 years after birth (7th follow-up). The consumption of drinking water was recorded by a standardized questionnaire. Statistical analyses were calculated with multiple linear regression models. RESULTS Children and mothers from Bochum showed higher PFOS and PFOA plasma concentrations than from Duisburg. The median concentrations (μg/l) for children were: PFOS 4.7 vs. 3.3; PFOA 6.0 vs. 3.6μg/l (p≤0.05). Consumption of >0.7 l (children) and >0.9 l (mothers) drinking water/day was associated with 13-18% higher PFOS, PFOA and PFHxS concentrations in children (p≤0.01), and 22% higher PFOA in mothers (p≤0.05). Within the Duisburg cohort, PFAA levels in children peaked in the 5th follow-up study (medians (μg/l): cord plasma: 2.7 (PFOS); 1.9 (PFOA); 5th follow-up: 3.6 (PFOS); 4.6 (PFOA); 7th follow-up: 3.3 (PFOS); 3.6 (PFOA)). PFOS concentrations in mothers declined from pregnancy to the 5th follow-up (medians: 8.7 vs. 4.0μg/l). CONCLUSION Residents exposed to PFOS and PFOA through drinking water showed significantly higher PFOS and PFOA concentrations in blood plasma. Although PFAA concentrations in the children slightly decreased from the 5th to the 7th follow-up, we detected increasing exposure trends with increasing age in the 7th follow-up.