Henriette Boye Kyhl

Human urinary excretion of non-persistent environmental chemicals: an overview of Danish data collected between 2006 and 2012

Several non-persistent industrial chemicals have shown endocrine disrupting effects in animal studies and are suspected to be involved in human reproductive disorders. Among the non-persistent chemicals that have been discussed intensively during the past years are phthalates, bisphenol A (BPA), triclosan (TCS), and parabens because of their anti-androgenic and/or estrogenic effects. Phthalates are plasticizers used in numerous industrial products. Bisphenol A is the main component of polycarbonate plastics and epoxy resins. Parabens and TCS are antimicrobial preservatives and other phenols such as benzophenone-3 (BP-3) act as a UV-screener, while chlorophenols and phenyl phenols are used as pesticides and fungicides in agriculture. In spite of the widespread use of industrial chemicals, knowledge of exposure sources and human biomonitoring studies among different segments of the population is very limited. In Denmark, we have no survey programs for non-persistent environmental chemicals, unlike some countries such as the USA (NHANES) and Germany (GerES). However, we have analyzed the excretion of seven parabens, nine phenols, and the metabolites of eight different phthalates in urine samples collected over the past 6 years from four Danish cohorts. Here, we present biomonitoring data on more than 3600 Danish children, adolescents, young men, and pregnant women from the general population. Our study shows that nearly all Danes were exposed to the six most common phthalates, to BPA, TCS, and BP-3, and to at least two of the parabens. The exposure to other non-persistent chemicals was also widespread. Our data indicate decreasing excretion of two common phthalates (di-n-butyl phthalate and di-(2-ethylhexyl) phthalate) over time.

Pregnancy and Birth Cohort Resources in Europe: a Large Opportunity for Aetiological Child Health Research

BACKGROUND During the past 25 years, many pregnancy and birth cohorts have been established. Each cohort provides unique opportunities for examining associations of early-life exposures with child development and health. However, to fully exploit the large amount of available resources and to facilitate cross-cohort collaboration, it is necessary to have accessible information on each cohort and its individual characteristics. The aim of this work was to provide an overview of European pregnancy and birth cohorts registered in a freely accessible database located at http://www.birthcohorts.net. METHODS European pregnancy and birth cohorts initiated in 1980 or later with at least 300 mother-child pairs enrolled during pregnancy or at birth, and with postnatal data, were eligible for inclusion. Eligible cohorts were invited to provide information on the data and biological samples collected, as well as the timing of data collection. RESULTS In total, 70 cohorts were identified. Of these, 56 fulfilled the inclusion criteria encompassing a total of more than 500,000 live-born European children. The cohorts represented 19 countries with the majority of cohorts located in Northern and Western Europe. Some cohorts were general with multiple aims, whilst others focused on specific health or exposure-related research questions. CONCLUSION This work demonstrates a great potential for cross-cohort collaboration addressing important aspects of child health. The web site, http://www.birthcohorts.net, proved to be a useful tool for accessing information on European pregnancy and birth cohorts and their characteristics.

Current exposure of 200 pregnant Danish women to phthalates, parabens and phenols

Many phthalates, parabens and phenols are suspected to have endocrine-disrupting properties in humans. They are found in consumer products, including food wrapping, cosmetics and building materials. The foetus is particularly vulnerable and exposure to these chemicals therefore is of concern for pregnant women. We investigated current exposure to several commonly used phthalates, parabens and phenols in healthy, pregnant Danish women. A total of 200 spot urine samples were collected between 8 and 30 weeks of gestation and analysed for metabolites of ten phenols, seven parabens and 16 phthalate by liquid chromatography-tandem mass spectrometry representing 26 non-persistent compounds. The majority of analytes were present in the urine sample collected from most women who participated. Thus, in 174 of the 200 women, metabolites of more than 13 (>50%) of 26 compounds were detected simultaneously. The number of compounds detected per woman (either as the parent compound or its metabolite(s)) ranged from 7 to 21 with a median of 16. The majority of compounds correlated positively with each other within and between chemical groups, suggesting combined exposure sources. Estimated daily intakes (DIs) of phthalates and bisphenol A (BPA) were below their individual tolerable DI (TDI) and with hazard quotients below 1. In conclusion, we found detectable levels of phthalate metabolites, parabens and phenols in almost all pregnant women, suggesting combined multiple exposures. Although the estimated DI of phthalates and BPA for an individual was below TDI, our results still raise concern, as current toxicological risk assessments in humans do not take into account simultaneous exposure. The true cumulative risk for the foetus may therefore be underestimated.

The Odense Child Cohort: Aims, Design, and Cohort Profile

BACKGROUND The importance of the environment on the development of the fetus and infant throughout early life is increasingly recognised. To study such effects, biological samples and accurate data records are required. Based on multiple data collection from a healthy pregnant population, the Odense Childhood Cohort (OCC) study aims to provide new information about the environmental impact on child health by sequential follow-up to 18 years of age among children born between 2010 and 2012. METHODS A total of 2874 of 6707 pregnancies (43%) were recruited between January 2010 and December 2012. Three hundred seventy-four have since left the study, leaving 2500 active families. The non-participants act as controls contributing data through local registries. Biological material, questionnaires, and registry data were compiled. Anthropometric data and other physical data were collected. RESULTS Two thousand five hundred families actively participated in the study with 2549 children. Sixty-four per cent of the fathers and 60% and 58% of the mothers, respectively, donated a blood sample at 10 and 28 weeks of gestation. On average, 69% completed questionnaires, 78% of the children were regularly examined, and had a blood sample taken (46%). The participating pregnant women differed from the non-participants in several respects: age, body mass index, smoking, parity, education, and ethnicity. The infants were comparable with respect to gender and mode of delivery. CONCLUSIONS The OCC provides material for in-depth analysis of environmental and genetic factors that are important for child health and disease. Registry data from non-participating women and infants are available which ensures a high degree of comparable data.

Prenatal Triclosan Exposure and Anthropometric Measures Including Anogenital Distance in Danish Infants.

Background: Triclosan (TCS) is widely used as an antibacterial agent in consumer products such as hand soap and toothpaste, and human exposure is widespread. TCS is suspected of having endocrine-disrupting properties, but few human studies have examined the developmental effects of prenatal TCS exposure. Objectives: We prospectively examined associations between prenatal TCS exposure and anthropometric measures at birth and anogenital distance (AGD) at 3 months of age. Methods: Pregnant women from the Odense Child Cohort (n = 514) provided urine samples at approximately gestational week 28 (median 28.7 weeks, range 26.4–34.0), and urinary TCS concentration was measured by isotope dilution TurboFlow–liquid chromatography–tandem mass spectrometry. Multiple linear regression analysis was used to examine associations between prenatal TCS exposure and measures of size at birth (birth weight, length, head and abdominal circumference) and AGD at 3 months of age (median 3.3 months, range 2.3–6.7 months), controlling for potential confounders. Results: Newborn boys in the highest quartile of prenatal TCS exposure had a 0.7-cm [95% confidence interval (CI): –1.2, –0.1, p = 0.01] smaller head circumference than boys in the lowest quartile. Additionally in boys, inverse associations of borderline statistical significance were observed between prenatal TCS exposure and abdominal circumference at birth and AGD at 3 months of age (p-values < 0.10). Prenatal TCS exposure was not significantly associated with any of the outcomes in girls. However, AGD was measured in fewer girls, and we observed no significant interactions between a child’s sex and prenatal TCS exposure in anthropometric measures at birth. Conclusion: Prenatal TCS exposure was associated with reduced head and abdominal circumference at birth and with reduced AGD at 3 months of age in boys, although the last two findings were statistically nonsignificant. These findings require replication but are compatible with an anti-androgenic effect of prenatal TCS exposure on fetal growth in boys. Citation: Lassen TH, Frederiksen H, Kyhl HB, Swan SH, Main KM, Andersson AM, Lind DV, Husby S, Wohlfahrt-Veje C, Skakkebæk NE, Jensen TK. 2016. Prenatal triclosan exposure and anthropometric measures including anogenital distance in Danish infants. Environ Health Perspect 124:1261–1268; http://dx.doi.org/10.1289/ehp.1409637

Prenatal Exposure to Phthalates and Anogenital Distance in Male Infants from a Low-Exposed Danish Cohort (2010-2012).

Background: Phthalates comprise a large class of chemicals used in a variety of consumer products. Several have anti-androgenic properties, and in rodents prenatal exposure has been associated with reduced anogenital distance (AGD)—the distance from the anus to the genitals in male offspring. Few human studies have been conducted, but associations between the anti-androgenic phthalates and male AGD have been reported. Objective: We aimed to study the association between phthalate exposure in late pregnancy in Danish women pregnant in 2010–2012 and AGD in their male infants at 3 months of age (n = 273). Methods: In the Odense child cohort study, urinary concentrations of 12 phthalate metabolites of diethyl, di-n-butyl, diisobutyl, di(2-ethylhexyl), butylbenzyl, and diisononyl phthalate (DEP, DnBP, DiBP, DEHP, BBzP, and DiNP, respectively) were measured among 245 mothers of boys at approximately gestational week 28 (range, 20.4–30.4) and adjusted for osmolality. AGD, penile width, and weight were measured 3 months after the expected date of birth. Associations between prenatal phthalate and AGD and penile width were estimated using multivariable linear regression adjusting for age and weight-for-age standard deviation score. Results: Phthalate levels were lower in this population than in a recent Swedish study in which phthalates were measured in the first trimester. No consistent associations were seen between any prenatal phthalate and AGD or penile width. Most associations were negative for exposures above the first quartile, and for ln-transformed exposures modeled as continuous variables, but there were no consistent dose–response patterns, and associations were not statistically significant (p > 0.05). Conclusion: We found no significant trends towards shorter AGD in boys with higher phthalates exposures in this low exposed Danish population. Citation: Jensen TK, Frederiksen H, Kyhl HB, Lassen TH, Swan SH, Bornehag CG, Skakkebaek NE, Main KM, Lind DV, Husby S, Andersson AM. 2016. Prenatal exposure to phthalates and anogenital distance in male infants from a low-exposed Danish cohort (2010–2012). Environ Health Perspect 124:1107–1113; http://dx.doi.org/10.1289/ehp.1509870

Association between prenatal exposure to perfluorinated compounds and symptoms of infections at age 1–4 years among 359 children in the Odense Child Cohort

INTRODUCTION Perfluorinated alkylated substances (PFAS) are persistent industrial chemicals that have resulted in global environmental exposures. Previous epidemiological studies have reported possible effects on the immune system after developmental PFAS exposure, but the possible impact on childhood infectious disease is unclear. OBJECTIVES To investigate the association between prenatal exposure to PFAS and symptoms of infections at age 1-4years. METHODS The Odense Child Cohort is an on-going prospective study on childrens health, where serum concentrations of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorodecanoic acid (PFDA) and perfluorononanoic acid (PFNA) were measured in 649 pregnant women before gestational week 16. Of these women, 359 reported on symptoms of infection in their child every two weeks for a one-year period. The association between prenatal exposure to PFAS and the symptoms was estimated using a logistic regression model and a negative binomial regression model. For the latter, the outcome was reported as an incidence rate-ratio (IRR), and all models were adjusted for maternal age, educational level, parity and child age. RESULTS On average, the children experienced symptoms of infection 23% of the time during one year. PFOS exposure in the high tertile compared to the low tertile was associated with a statistically significant increased proportion of days with fever (IRR: 1.65 (95% CI: 1.24, 2.18), P-trend<0.001) and an increased odds of experiencing days with fever above the median (OR: 2.35 (95% CI: 1.31, 4.11). The latter tendency was also apparent for PFOA (OR: 1.97 (95% CI: 1.07, 3.62). Further, higher concentrations of PFOS and PFOA tended to increase the number of episodes of co-occurrence of fever and coughing and fever and nasal discharge during the one-year study period. CONCLUSION We found a positive association between prenatal exposure to PFOS and PFOA and the prevalence of fever, which may be a sensitive marker of infection. This finding is in agreement with an immunotoxic effect of prenatal exposure to PFAS. The wider implications for childhood infectious disease deserve attention.

Maternal use of mild analgesics during pregnancy associated with reduced anogenital distance in sons: a cohort study of 1027 mother-child pairs

STUDY QUESTION Is maternal use of mild analgesics in pregnancy associated with anogenital distance (AGD)—the distance from the anus to the genitals—in the offspring? SUMMARY ANSWER Maternal use of mild analgesics [especially simultaneous use of paracetamol and nonsteroidal anti-inflammatory drugs (NSAIDs)] during pregnancy was associated with a shorter AGD in boys whereas no effect was found in girls. WHAT IS KNOWN ALREADY Mild analgesics including paracetamol (acetaminophen) and NSAIDs (e.g. ibuprofen and acetyl salicylic acid) have endocrine disrupting properties and in utero exposure reduces AGD in male rats. In humans, maternal exposure has been associated with cryptorchidism and hypospadias in male offspring but no studies have examined AGD. STUDY DESIGN, SIZE, DURATION A prospective birth cohort study. Between 2010 and 2012, 2500 pregnant women were recruited from the Odense Child Cohort. Children were examined 3 months after the expected date of birth. PARTICIPANTS/MATERIALS, SETTING, METHODS Pregnant women were asked about use of medication including mild analgesics (paracetamol and NSAID) during pregnancy at recruitment (gestational age (GA) week 10–27) and at GA week 28. AGD and penile width were measured 3 months after expected date of birth by trained personnel. A total of 1027 women answered both questionnaires and their children were examined. Associations between prenatal exposure to mild analgesics and AGD and penile width were estimated using multivariable linear regression adjusting for age and weight-for-age SD score. MAIN RESULTS AND THE ROLE OF CHANCE A total of 40% of the women reported use of paracetamol and/or NSAIDs (4.4%) during the first 28 weeks of pregnancy. Exposure to analgesics during pregnancy was associated with a reduced AGD in boys, although statistically significant only for NSAIDs. The association was significant among 20 boys exposed to both paracetamol and NSAIDs (AGD −4.1 mm; CI 95%: −6.4; −1.7). Maternal intake of analgesics did not show any clear association with AGD in female offspring. No effect on penile width was found. LIMITATIONS REASONS FOR CAUTION Only 27 boys and 18 girls were exposed to NSAIDs and most of them were also exposed to paracetamol. This makes it impossible to distinguish between exposures to NSAIDs alone and a potential mixture effect. Moreover, use of mild analgesics was self-reported up to 2 months after intake, which could have caused misclassification of exposure but is probably not associated with AGD as this was unknown to the women at time of reply to the questionnaire thereby underestimating the association. Confounding by indication may also explain our findings, as the condition for which the analgesic was taken may be associated with a reduction in AGD, rather than the use of the analgesic medication. This is the first study to report such an association in humans and further studies are needed to confirm our findings. WIDER IMPLICATIONS OF THE FINDINGS A negative association was observed between exposure to analgesics during pregnancy and AGD in boys, suggesting disruption of androgen action. The health implications of a shorter AGD are still uncertain, but in cross-sectional studies among adult men a shorter AGD is associated with poorer semen quality and lower testosterone. As 41% of the women used these painkillers the finding are of public health importance and pregnant women should be advised about the potentially harmful effects of painkiller use. STUDY FUNDING/COMPETING INTEREST(S) The study was funded by the Danish Environmental Protection Agency by way of the Center on Endocrine Disruptors Danish Center for Hormone Disrupting Chemicals, the Danish Foundation for Scientific Innovation and Technology (09-067180), the Danish Research Council (4004-00352B_FSS), Novo Nordic Foundation (NNF15OC0017734), Ronald McDonald Children Foundation, K.A. Rohdes and wifes Foundation, Odense University Hospital and Region of Southern Denmark, Municipality of Odense, the Danish Council for Strategic Research, Program Commission on Health, Food and Welfare (2101-08-0058), Odense University Hospital Research Foundation and Odense Patient data Exploratory Network (OPEN). The authors declare they have no competing interests. TRIAL REGISTRATION NUMBER Not applicable.

Gestational Diabetes Mellitus: Does One Size Fit All? A Challenge to Uniform Worldwide Diagnostic Thresholds

OBJECTIVE To define the prevalence and pregnancy outcomes related to elevated fasting venous plasma glucose (FVPG) in a Danish pregnancy cohort. RESEARCH DESIGN AND METHODS This was an observational cohort study including 1,516 women without gestational diabetes mellitus (GDM) by Danish criteria. FVPG measured at 28 weeks’ gestation was related to pregnancy outcomes. RESULTS With use of the World Health Organization (WHO) 2013 threshold of FVPG ≥5.1 mmol/L, 40.1% of the cohort qualified as having GDM. There was no evidence of excess fetal growth, hypertension in pregnancy, or cesarean delivery in women with FVPG <5.6 mmol/L. CONCLUSIONS The WHO 2013 FVPG threshold for GDM is unsuitable for Denmark. It inappropriately labels as having GDM an unmanageably large number of women who are at low absolute risk of pregnancy complications.

Insulin resistance in pregnant women with and without polycystic ovary syndrome, and measures of body composition in offspring at birth and three years of age

Polycystic ovary syndrome is associated with obesity and insulin resistance in the non‐pregnant state, but little is known about insulin sensitivity in the pregnant state. Our objective was to compare insulin resistance in pregnant women with and without polycystic ovary syndrome and explore the impact of polycystic ovary syndrome on body composition in offspring at birth and at three years of age.