Maternal concentrations of phthalates and Attention-Deficit Hyperactivity Disorder (ADHD-) related symptoms in children aged 2 to 4 years from Odense child cohort

BACKGROUND

Phthalates are endocrine disrupting chemicals used in everyday consumer products. Several epidemiological studies have examined the association between prenatal phthalate concentration and Attention-Deficit Hyperactivity Disorder (ADHD) in offspring, but the findings have been inconclusive.

OBJECTIVES

To investigate the association between maternal urinary concentrations of phthalate metabolites during pregnancy and ADHD related symptoms in children at 2 to 4 years in a large prospective cohort.

METHODS

In the Odense Child Cohort from Denmark were women recruited in early pregnancy from 2010 to 2012. Phthalate concentrations were measured in urine samples collected in 3rd trimester and separated into low and high weight phthalates. Parents filled in the Child Behavior Checklist for ages 1.5 to 5 years (CBCL/1½-5), including a 6-item ADHD symptom scale at children aged 2 to 4 years. Data were analysed by use of adjusted negative binomial regression.

RESULTS

A total of 658 mother-child pairs were included. Urinary phthalate metabolite concentrations were generally low compared to previous cohorts. A doubling in maternal concentration of the low-weighted phthalate metabolite MCPP was significantly associated with lower ADHD symptoms score in children (IRR: 0.95 (95 % CI 0.91-0.98)), strongest in girls (IRR: 0.92 (0.87-0.98)). Sex differences were observed. High maternal phthalate metabolite concentrations were associated with lower ADHD symptom score in girls, significant trends across tertile of MCPP and MnBP (p = 0.018, p = 0.038, respectively). In boys, maternal concentrations of high-molecular-weight phthalates (MBzP, ∑DiNP and ∑DEHP) were associated with an almost significantly higher ADHD symptom score (IRR for a doubling in concentration: 1.04 (95 % CI: 0.99-1.10), IRR: 1.05 (95 % CI: 0.97-1.13), IRR: 1.04 (95 % CI: 0.99-1.10), respectively).

CONCLUSION

Maternal concentration of the low-weighted phthalate metabolite MCPP was significantly associated with a lower ADHD symptom score in children, strongest in girls. Maternal concentrations of high-molecular-weight phthalates were associated with non-significant increase in ADHD symptom score in boys.

Prenatal Exposure to Butyl Paraben Is Associated With Fat Percentage in 7-Year-Old Boys

CONTEXT

Parabens are used as preservatives in consumer products but are suspected of having endocrine-disrupting properties. A recent study reported an association between in utero exposure to butyl paraben and overweight in childhood, with a stronger trend in girls.

OBJECTIVE

We therefore studied the association between parabens in maternal urine in third trimester and fat percentage in children aged 7 years.

DESIGN, SETTING, AND PARTICIPANTS

We used data from the Odense Child Cohort, a mother-child cohort with enrollment from 2010 to 2012, in which the children are followed. Paraben concentration was assessed in maternal urine at median gestational week 28.7 and body composition measured as total, gynoid, and android fat percentages assessed by dual X-ray absorptiometry in their children at age 7 years.

MAIN OUTCOME MEASUREMENTS

Total, gynoid, and android fat percentages and z-score for body mass index.

INTERVENTIONS

None.

RESULTS

Paraben exposure was low. In multivariate linear regressions, detection of butylparaben in maternal urine was associated with an increase of 17% [95% confidence intervals (CI) 3.0%, 32%] in total body fat percentage and an increase of 23% (95% CI 5.1%, 43%) in android fat percentage in boys, compared to boys whose mother had no detectable butylparaben in urine. No significant associations between in utero exposure to methyl-, ethyl- or propyl parabens and body composition were found, and no significant associations were seen in girls.

CONCLUSION

Our findings suggest that parabens, which are believed to have low toxicity, may affect obesity development at vulnerable time periods during development.

Exposure to perfluoroalkyl substances and blood pressure in pregnancy among 1436 women from the Odense Child Cohort

BACKGROUND

Previous studies of association between exposure to poly- and perfluoroalkyl substances (PFAS) and gestational hypertension (GH) and preeclampsia (PE) have shown conflicting results, but most dichotomized outcome and did not study continuous blood pressure (BP) changes.

OBJECTIVES

To study the association between PFAS exposure in early pregnancy and maternal BP trajectories in pregnancy, gestational hypertension and preeclampsia.

METHODS

1436 women were enrolled in the Odense Child Cohort in early pregnancy and had a serum sample drawn, from which perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) were measured using LC-MS/MS. Repeated BP measurements through pregnancy and information on PE were obtained from hospital files. Adjusted linear mixed models were used to investigate association between PFAS exposure and BP trajectory. Associations between PFAS and PE and GH were assessed by Cox proportional hazards model.

RESULTS

All women had measurable concentrations of PFAS. In all of many comparisons higher PFAS exposure (apart from PFHxS) was associated with higher systolic (SBP) and diastolic (DBP) blood pressures, although not all were significant, which is unlikely to be due to chance. After adjustment, each doubling in PFOS or PFOA exposure was associated with 0.47 mmHg (95% CI: -0.13; 1.08) and 0.36 mmHg (-0.19; 0.92) higher SBP; and 0.58 mmHg (0.13; 1.04) and 0.37 mmHg (-0.05; 0.79) higher DBP. No clear associations between PFAS exposure and PE or GH were found.

DISCUSSION

The magnitude of the association between PFAS exposure and BP might appear small, statistically non-significant and the possible clinical importance low. However, at a population level this may slightly shift the distribution of BP towards an increased incidence of GH. If BP increases in pregnancy, it may have long-term impact on health not only of the pregnant woman but also of her offspring.

Prenatal paraben exposure and anogenital distance and reproductive hormones during mini-puberty: A study from the Odense Child Cohort

BACKGROUND

Parabens are added to personal care products as antimicrobial preservatives. They have been suggested to have endocrine disrupting abilities. Prenatal exposure to parabens has been associated with reproductive endpoints including reduced male anogenital distance (AGD, distance from anus to genitals), which is sensitive to prenatal anti-androgenic exposure.

OBJECTIVES

To study the associations between maternal paraben concentrations in second trimester urine and AGD and reproductive hormone concentrations at 3 months of age in offspring.

METHODS

Pregnant women from Odense, Denmark were included in early pregnancy from 2010 to 12, and their children are being followed up. Fasting spot urine samples from 536 pregnant women were analyzed for methylparaben (MeP), ethyl-paraben (EtP), iso-propylparaben (i-PrP), n-propylparaben (n-PrP), n-butylparaben (n-BuP) and benzylparaben (BzP) by liquid chromatography tandem mass spectrometry and thereafter osmolarity adjusted. Three months after expected date of birth, AGD was measured in 452 children, and serum concentrations of follicle stimulating hormone (FSH), luteinizing (LH), testosterone, dehydroepiandrosterone-sulphate (DHEAS), androstenedione and 17-hydroxyprogesterone (17-OHP) were measured in 198 children. Maternal paraben exposure was categorized into tertiles or below and above level of detection, and sex-stratified multiple linear regression analyses were performed with AGD or reproductive hormones as outcomes.

RESULTS

Most pregnant women had low concentrations of parabens in urine, but 10% exceeded the threshold for adverse estrogenic effects. Higher maternal paraben exposure was associated with shorter AGD in male offspring and longer AGD in girls, although only significant for MeP in boys. In addition, FSH, LH, DHEAS, 17-OHP concentrations were lower in girls with high prenatal paraben exposure, whereas no consistent pattern was found in boys.

DISCUSSION

The endocrine disrupting abilities of parabens may affect humans at vulnerable time periods during development, which may have long term impact on reproductive function. This is the first study to find these associations in girls and our findings need confirmation.

Prenatal exposure to pyrethroid and organophosphate insecticides and language development at age 20-36 months among children in the Odense Child Cohort

BACKGROUND

Prenatal exposure to organophosphate and pyrethroid insecticides has been associated with impaired neurodevelopment. Few longitudinal studies have investigated associations with early language development in populations with mainly low dietary exposure.

OBJECTIVE

To investigate associations between biomarkers of maternal gestational exposure to organophosphate and pyrethroid insecticides and the child's language development at age 20-36 months in the prospective Odense Child Cohort.

METHODS

Metabolites of organophosphate and pyrethroid insecticides were measured in maternal urine samples collected at gestational week 28. Language development was assessed among 755 singletons at age 20-36 months using the Vocabulary and Complexity scores of the MacArthur-Bates Communicative Development Inventories, standardized into age and sex specific percentile scores according to a Danish reference study. Multiple logistic regression models were used to estimate the odds of scoring below the 15th percentile scores in relation to maternal urinary insecticide metabolite concentrations after adjustment for confounders.

RESULTS

The generic pyrethroid metabolite 3-phenoxybenzoic acid (3-PBA) and the chlorpyrifos metabolite 3,5,6-trichloro-2-pyridinol (TCPY) were detectable in more than 90% of the urine samples analyzed. Likewise, 82.2% had detectable concentrations of diethyl phosphates (DE) and 58.4% of dimethyl phosphates (DM), both of which are common metabolites of organophosphate insecticides. None of the metabolites was associated with higher odds of delayed results below the 15th percentile language scores. In contrast, reduced probability for scoring below the 15th percentile Vocabulary score was seen for the highest tertile of 3-PBA in boys and for the upper tertile of TCPY and DE in girls.

CONCLUSION

In this prospective cohort, with predominantly dietary insecticide exposure, we found no evidence that gestational exposure to organophosphate or pyrethroid insecticides adversely affected early language development in the children. The observed indication of a positive effect of insecticides on language development may be explained by residual and unmeasured confounding from socioeconomic factors and dietary habits. Follow-up of these children should include assessment of more complex cognitive functions in later childhood, as well as associations with their own postnatal insecticide exposure.

Exposure to perfluoroalkyl substances during fetal life and hospitalization for infectious disease in childhood: A study among 1,503 children from the Odense Child Cohort

INTRODUCTION

The immunosuppressive properties of PFASs are widely recognized. Early-life exposure to PFAS has been linked to reduced immune response to childhood vaccinations and increased rates of common infectious diseases, but implications for hospitalizations are unclear.

OBJECTIVES

To investigate the association between maternal serum concentrations of five PFASs during pregnancy and the child's rate of hospitalization due to common infectious diseases between birth and 4 years of age.

METHODS

Serum samples from first trimester pregnant women from the Odense Child Cohort (OCC) collected in 2010-2012 were analyzed for concentrations of perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and three other PFASs. Data on child hospitalizations with an ICD-10 code for infectious disease was obtained from the Danish National Patient Register. The following were identified: upper respiratory tract infections (URTI), lower respiratory tract infections (LRTI), gastrointestinal infections (GI), and other infections. The Andersen-Gill Cox proportional hazard model for recurrent events was used to investigate the association between PFAS exposure and hospitalizations. The resulting estimates were hazard ratios (HRs), which express the relative change in the instantaneous risk of hospitalization with a doubling in maternal PFAS concentration.

RESULTS

A total of 1,503 mother-child pairs were included, and 26% of the children were hospitalized at least once for infectious disease. A doubling in maternal PFOS concentration was associated with a 23% increase in the risk of hospitalization due to any infection (HR: 1.23 (95% CI: 1.05, 1.44). There was indication of an interaction between child sex and PFOS (p = 0.07) and PFDA (p = 0.06), although in opposite directions. Further, every doubling of PFOA or PFOS increased the risk of LRTI by 27% (HR: 1.27 (1.01, 1.59)) and 54% (HR: 1.54 (1.11, 2.15)), respectively. Similar tendencies were seen for URTI and the group of other infections. For GIs, the opposite pattern of association was seen as HR's were consistently below 1 (PFOA, HR: 0.55 (0.32, 0.95)).

DISCUSSION

We found an association between PFOS and the overall risk of infectious disease, and between PFOS and PFOA exposures and the risk of LRTI's. These results are in agreement with previous findings from the OCC, in which maternal PFOS and PFOA concentrations were positively associated with the number of days that the children experienced fever, thereby suggesting that PFOS and PFOA may affect the prevalence of both mild and more severe infectious diseases even in a rather low-exposed population.

Prenatal exposure to bisphenol A and autistic- and ADHD-related symptoms in children aged 2 and5 years from the Odense Child Cohort

BACKGROUND

Bisphenol A (BPA) is a non-persistent chemical with endocrine disrupting abilities used in a variety of consumer products. Fetal exposure to BPA is of concern due to the elevated sensitivity, which particularly relates to the developing brain. Several epidemiological studies have investigated the association between prenatal BPA exposure and neurodevelopment, but the results have been inconclusive.

OBJECTIVE

To assess the association between in utero exposure to BPA and Attention Deficit/Hyperactivity Disorder (ADHD-) symptoms and symptoms of Autism Spectrum Disorder (ASD) in 2 and 5-year old Danish children.

METHOD

In the prospective Odense Child Cohort, BPA was measured in urine samples collected in gestational week 28 and adjusted for osmolality. ADHD and ASD symptoms were assessed with the use of the ADHD scale and ASD scale, respectively, derived from the Child Behaviour Checklist preschool version (CBCL/1½-5) at ages 2 and 5 years. Negative binomial and multiple logistic regression analyses were performed to investigate the association between maternal BPA exposure (continuous ln-transformed or divided into tertiles) and the relative differences in ADHD and ASD problem scores and the odds (OR) of an ADHD and autism score above the 75th percentile adjusting for maternal educational level, maternal age, pre-pregnancy BMI, parity and child age at evaluation in 658 mother-child pairs at 2 years of age for ASD-score, and 427 mother-child pairs at 5 years of age for ADHD and ASD-score.

RESULTS

BPA was detected in 85.3% of maternal urine samples even though the exposure level was low (median 1.2 ng/mL). No associations between maternal BPA exposure and ASD at age 2 years or ADHD at age 5 years were found. Trends of elevated Odds Ratios (ORs) were seen among 5 year old children within the 3rd tertile of BPA exposure with an ASD-score above the 75th percentile (OR = 1.80, 95% CI 0.97,3.32), being stronger for girls (OR = 3.17, 95% CI 1.85,9.28). A dose-response relationship was observed between BPA exposure and ASD-score at 5 years of age (p-trend 0.06) in both boys and girls, but only significant in girls (p-trend 0.03).

CONCLUSION

Our findings suggest that prenatal BPA exposure even in low concentrations may increase the risk of ASD symptoms which may predict later social abilities. It is therefore important to follow-up these children at older ages, measure their own BPA exposure, and determine if the observed associations persist.

Maternal phthalate exposure associated with decreased testosterone/LH ratio in male offspring during mini-puberty. Odense Child Cohort

BACKGROUND

Phthalates are plastic softeners with anti-androgenic properties. Prenatal exposure has led to lower testosterone (T) levels and smaller testicles in adult rats. To our knowledge, no studies have examined associations between prenatal phthalate exposure and sex hormone concentrations in infants.

OBJECTIVE

To study associations between phthalate exposure in Danish pregnant women and T, luteinizing hormone (LH), follicle stimulating hormone (FSH), Δ4-androstenedione (adion), 17α-hydroxyprogesterone (17-OHP) dehydroepiandrosterone sulfate (DHEAS) concentrations in their infants (N = 479) during mini-puberty.

METHODS

Concentrations of 12 phthalate metabolites from six phthalate diesters were measured in urine samples collected from 2010 to 2012 from 479 pregnant women participating in the Odense Child Cohort at gestational week 28 (range 20.4-30.4). Serum T, LH, FSH, adion, 17-OHP, DHEAS, weight and height were measured approximately three months after expected date of birth. Associations between prenatal phthalate exposure and gonadotropin and androgen metabolite concentrations were estimated in boys and girls separately in adjusted linear regression models.

RESULTS

T concentration was lower in boys prenatally exposed to phthalates. Maternal urinary concentrations of summed mono-iso-butyl and mono-n-butyl phthalate (∑MBP_i+n) and summed metabolites of di-iso-nonyl phthalate (∑DiNP_m) were associated with lower T/LH ratio in male offspring and a dose-response association was found. FSH was 14% (95% CI: 1; 25) lower among male offspring from mothers exposed to ∑DiNP_m in the highest compared to the lowest tertile. No association was found for girls.

CONCLUSION

Even in these low exposed children, we found a significant decrease in T/LH ratio during mini-puberty in boys prenatally exposed to phthalates, which may suggest impairment of Leydig cells. The children will be followed as they approach adrenarche and pubarche in order to assess if long-term adverse effects persist.

Anogenital distance in children born of mothers with polycystic ovary syndrome: the Odense Child Cohort

STUDY QUESTION

Are higher testosterone levels during pregnancy in women with polycystic ovary syndrome (PCOS) associated with longer offspring anogenital distance (AGD)?

SUMMARY ANSWER

AGD was similar in 3-month-old children born of mothers with PCOS compared to controls.

WHAT IS KNOWN ALREADY

AGD is considered a marker of prenatal androgenization.

STUDY DESIGN, SIZE, DURATION

Maternal testosterone levels were measured by mass spectrometry at Gestational Week 28 in 1127 women. Maternal diagnosis of PCOS before pregnancy was defined according to Rotterdam criteria. Offspring measures included AGD from anus to posterior fourchette (AGDaf) and clitoris (AGDac) in girls and to scrotum (AGDas) and penis (AGDap) and penile width in boys and body composition (weight and BMI SD scores) at age 3 months.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study was part of the prospective study, Odense Child Cohort (OCC), and included mothers with PCOS (n = 139) and controls (n = 1422). The control population included women with regular menstrual cycles (<35 days) before conception and no signs of androgen excess (hirsutism and/or acne).

MAIN RESULTS AND THE ROLE OF CHANCE

AGD measures were comparable in offspring of women with PCOS compared to controls (all P > 0.2) despite significantly higher maternal levels of total testosterone (mean: 2.4 versus 2.0 nmol/l) and free testosterone (mean: 0.005 versus 0.004 nmol/l) in women with PCOS versus controls (both P < 0.001). In women with PCOS, maternal testosterone was an independent positive predictor of offspring AGDas and AGDap in boys. Maternal testosterone levels did not predict AGD in girls born of mothers with PCOS or in boys or girls born of women in the control group.

LIMITATIONS, REASONS FOR CAUTION

The diagnosis of PCOS was based on retrospective information and questionnaires during pregnancy. Women participating in OCC were more ethnically homogenous, leaner, more educated and less likely to smoke compared to the background population. Our study findings, therefore, need to be reproduced in prospective study cohorts with PCOS, in more obese study populations and in women of other ethnicities.

WIDER IMPLICATIONS OF THE FINDINGS

Our finding of the same AGD in girls born of mothers with PCOS compared to controls expands previous results of studies reporting longer AGD in adult women with PCOS. Our results suggest that longer AGD in adult women with PCOS could be the result of increased testosterone levels in puberty, perhaps in combination with weight gain.

STUDY FUNDING/COMPETING INTEREST(S)

Financial grants for the study were provided by the Danish Foundation for Scientific Innovation and Technology (09-067180), Ronald McDonald Children Foundation, Odense University Hospital, the Region of Southern Denmark, the Municipality of Odense, the Mental Health Service of the Region of Southern Denmark, The Danish Council for Strategic Research, Program Commission on Health, Food and Welfare (2101-08-0058), Odense Patient data Explorative Network, Novo Nordisk Foundation (grant no. NNF15OC00017734), the Danish Council for Independent Research and the Foundation for research collaboration between Rigshospitalet and Odense University Hospital and the Health Foundation (Helsefonden). There is no conflict of interest of any author that could be perceived as prejudicing the impartiality of the research reported.

Perfluoroalkyl Substance Exposure Early In Pregnancy Was Negatively Associated With Late Pregnancy Cortisone Levels

INTRODUCTION

During pregnancy, maternal cortisol levels are increased 3-fold by the third trimester. The enzyme 11β-hydroxysteroid dehydrogenase (11β-HSD, isoforms 1 and 2) regulates the balance between cortisol and cortisone levels. Perfluoroalkyl substances (PFAS) have been reported to inhibit 11β-HSD1 and more potently 11β-HSD2, which could lead to reduced levels of cortisol and more extensively cortisone.

AIM

The aim of this work is to investigate a possible effect of early pregnancy PFAS exposure on late pregnancy activity of 11β-HSD1 and 11β-HSD2 assessed by cortisol and cortisone levels in diurnal urine (dU) and blood samples.

METHODS

This study is part of the prospective cohort study, Odense Child Cohort (OCC). A total of 1628 pregnant women had serum (S) concentrations of 5 PFAS (perfluorooctanoic acid [PFOA], perfluorooctane sulfonic acid [PFOS], perfluorohexane sulfonic acid [PFHxS], perfluorononanoic acid [PFNA], and perfluorodecanoic acid (PFDA)) measured in the first trimester (median gestational week, GW 11). dU cortisol and cortisone (n = 344) and S-cortisol (n = 1048) were measured in the third trimester (median GW 27).

RESULTS

In multiple regression analyses, a 2-fold increase in S-PFOS was significantly associated with lower dU-cortisone (β = -9.1%, P < .05) and higher dU-cortisol/dU-cortisone (dU-C/C) (β = 9.3%, P < .05). In crude models, a doubling in PFOS, PFOA, PFHxS, and PFNA concentrations were associated with a significant increase in S-cortisol; however, these associations became insignificant after adjustment.

CONCLUSION

Early pregnancy maternal S-PFAS were inversely associated with late pregnancy dU-cortisone, indicating reduced activity of 11β-HSD2.

MON-LB131 Perfluoroalkyl Substance Exposure Was Negatively Associated With Cortisone Levels in Pregnancy

Introduction: During pregnancy, maternal cortisol levels are increased threefold by third trimester. The enzyme 11β-hydroxysteroid dehydrogenase (11β-HSD, isoforms 1 and 2) regulates cortisol levels by the conversion between cortisol and cortisone. Perfluoroalkyl substances (PFAS) are persistent chemicals with suspected endocrine disrupting abilities applied in consumer products. PFAS have been reported to inhibit 11β-HSD1 and 11β-HSD2, which could lead to reduced levels of cortisol and cortisone.

Aim: To investigate a possible effect of early pregnancy PFAS exposure on late pregnancy activity of 11β-HSD1 and 11β-HSD2 assessed by cortisol and cortisone levels in urine and blood samples.

Methods: The study is part of the prospective cohort study, Odense Child Cohort (OCC). A total of 1,826 pregnant women had serum (S) concentrations of five PFAS (Perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA)) measured in first trimester (median gestational week (GW) 11). Diurnal urinary (dU) cortisol and cortisone (n=344), and S-cortisol (n=1,048) were measured in third trimester (median GW 27).

Results: In multiple regression analyses, a two-fold increase in S-PFOS was significantly associated with lower dU-cortisone (β=-9.1%, p<0.05) and higher dU-cortisol/dU-cortisone (dU-C/C) (β=9.3%, p<0.05). The same trend was demonstrated for PFOA, PFHxS, PFNA, and PFDA. In crude models, a doubling in PFOS, PFOA, PFHxS, and PFNA concentrations were associated with a significant increase in S-cortisol, however, these associations became insignificant after adjustment.

Conclusion: Early pregnancy concentrations of maternal S-PFAS were inversely associated with late pregnancy dU-cortisone, indicating reduced activity of 11β-HSD2.

Maternal phthalate exposure and asthma, rhinitis and eczema in 552 children aged 5 years; a prospective cohort study

BACKGROUND

Prenatal phthalate exposure has been suggested to alter immune responses and increase the risk of asthma, eczema and rhinitis. However, few studies have examined the effects in prospective cohorts and only one examined rhinitis. We therefore studied associations between maternal urinary concentrations of phthalate metabolites and asthma, eczema and rhinitis in offspring aged 5 years.

METHODS

From 552 pregnant women in the Odense Child Cohort, we quantified urinary concentrations of 12 phthalate metabolites in third trimester. We assessed asthma, rhinitis and eczema in their offspring at age 5 years with a questionnaire based on the International Study of Asthma and Allergies in Childhood (ISAAC), and conducted logistic regression adjusting for relevant confounders.

RESULTS

7.4% of the children had asthma, 11.7% eczema and 9.2% rhinitis. Phthalate exposure was low compared to previous cohorts. No significant associations between prenatal phthalate exposure and asthma were found. Odds ratios (ORs) of child rhinitis with a doubling in ΣDiNP_m and di-2-ethylhexyl phthalate metabolite (ΣDEHP_m) concentrations were, respectively, 1.15 (95% confidence interval (CI) 0.97,1.36) and 1.21 (CI 0.93,1.58). The OR of eczema when doubling ΣDiNP_m was 1.24 (CI 1.00,1.55), whereas the OR of using medicine against eczema when doubling a di-ethyl phthalate (DEP) metabolite was 0.81 (CI 0.68,0.96).

CONCLUSION

The lack of association between maternal phthalate exposure and asthma in the offspring may be due to low exposure and difficulties in determining asthma in 5-year-olds. The higher odds of rhinitis may raise public concern but further research in larger cohorts of older children is warranted.

Prenatal exposure to perfluorodecanoic acid is associated with lower circulating concentration of adrenal steroid metabolites during mini puberty in human female infants. The Odense Child Cohort

BACKGROUND

Fetal programming of the endocrine system may be affected by exposure to perfluoroalkyl substances (PFAAs), as they easily cross the placental barrier. In vitro studies suggest that PFAAs may disrupt steroidogenesis. "Mini puberty" refers to a transient surge in circulating androgens, androgen precursors, and gonadotropins in infant girls and boys within the first postnatal months. We hypothesize that prenatal PFAA exposure may decrease the concentrations of androgens in mini puberty.

OBJECTIVES

To investigate associations between maternal serum PFAA concentrations in early pregnancy and serum concentrations of androgens, their precursors, and gonadotropins during mini puberty in infancy.

METHODS

In the prospective Odense Child Cohort, maternal pregnancy serum concentrations of five PFAAs: Perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) were measured at median gestational week 12 (IQR: 10, 15) in 1628 women. Among these, offspring serum concentrations of dehydroepiandrosterone (DHEA), dehydroepiandrosterone-sulfate (DHEAS), androstenedione, 17-hydroxyprogesterone (17-OHP), testosterone, luteinizing (LH) and follicle stimulating hormones (FSH) were measured in 373 children (44% girls; 56% boys) at a mean age of 3.9 (±0.9 SD) months. Multivariate linear regression models were performed to estimate associations.

RESULTS

A two-fold increase in maternal PFDA concentration was associated with a reduction in DHEA concentration by -19.6% (95% CI: -32.9%, -3.8%) in girls. In girls, also, the androstenedione and DHEAS concentrations were decreased, albeit non-significantly (p < 0.11), with a two-fold increase in maternal PFDA concentration. In boys, no significant association was found between PFAAs and concentrations of androgens, their precursors, and gonadotropins during mini puberty.

CONCLUSION

Prenatal PFDA exposure was associated with significantly lower serum DHEA concentrations and possibly also with lower androstenedione and DHEAS concentrations in female infants at mini puberty. The clinical significance of these findings remains to be elucidated.

Association between prenatal exposure to perfluoroalkyl substances and asthma in 5-year-old children in the Odense Child Cohort

BACKGROUND

Asthma is the most common non-communicable disease in children. Prenatal exposure to perfluoroalkyl substances (PFASs), a group of persistent environmental chemicals with endocrine disrupting abilities, has been associated with immunomodulation and may contribute to the aetiology of asthma. We investigated the associations between prenatal exposure to five PFASs and asthma in 5-year-old children.

METHODS

We studied 981 mother-child pairs within the Odense Child Cohort (OCC), Denmark. We measured perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) in maternal serum donated in early pregnancy. A standardized questionnaire based on the International Study of Asthma and Allergies in Childhood (ISAAC) was used to assess wheeze, self-reported asthma and doctor-diagnosed asthma among children at age 5 years. Associations were examined using logistic regression analyses adjusting for parity, maternal educational level, maternal pre-pregnancy BMI, asthma predisposition and child sex.

RESULTS

Among the 5-year-old children 18.6% reported wheeze and 7.1% reported asthma. We found no association between prenatal exposure to PFAS and doctor-diagnosed asthma or wheeze. Prenatal PFAS exposure was associated with self-reported asthma, although only significant for PFNA (OR = 1.84, 95% CI 1.03,3.23).

CONCLUSION

Our findings support the suggested immunomodulatory effects of PFASs, however, additional studies are warranted. In order to verify our findings, it is important to re-examine the children with postnatal measurements of serum PFAS concentrations and additional clinical diagnostic testing at an older age where an asthma diagnosis is more valid.

Maternal urinary concentrations of pyrethroid and chlorpyrifos metabolites and attention deficit hyperactivity disorder (ADHD) symptoms in 2-4-year-old children from the Odense Child Cohort

BACKGROUND

Pyrethroids and chlorpyrifos are widely used insecticides, but the potential impact of prenatal exposure on child neurodevelopment has only been addressed in few longitudinal studies.

OBJECTIVES

To investigate associations between prenatal exposure to pyrethroids and chlorpyrifos and traits of ADHD in 2-4-year-old children.

METHODS

Metabolites of chlorpyrifos and pyrethroids were measured in maternal urine collected at gestational week 28 among 1207 women from the Odense Child Cohort. Of these, 948 completed the Child Behavior Check List for ages 1.5-5 years (CBCL: 1½-5). Negative binomial and logistic regression models were used to estimate relative differences in ADHD problem scores (CBCL: 1½-5 subscale) expressed as the ratio of expected scores between exposure groups and the odds (OR) of scoring equal to or above the 90^th percentile in relation to maternal urinary metabolite concentrations (continuous ln₂-transformed or categorized into tertiles). The analyses were adjusted for maternal education level, parental psychiatric diagnosis, child age and sex.

RESULTS

The chlorpyrifos metabolite, 3,5,6-trichloro-2-pyridinol (TCPY), the generic pyrethroid metabolite, 3-phenoxybenzoic acid (3-PBA), and the metabolite of trans-isomers of permethrin, cypermethrin, and cyfluthrin, trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (trans-DCCA), were detected in 90%, 94%, and 11%, respectively, of the urine samples. Each doubling in maternel 3-PBA concentration was associated with a 3% increase in the ADHD score (Ratio: 1.03 (95% CI: 1.00,1.07)) and a 13% higher odds of having a ADHD score ≥ the 90^th percentile (OR: 1.13 (1.04,1.38)). Similar associations were seen for 3-PBA as categorical variable (p-trend=0.052 in negative binimoal regression, p-trend=0.007 in logistic regression). Furthermore, concurrent concentrations of 3-PBA and TCPY above their medians were associated with higher ADHD score (Ratio: 1.20 (1.04, 1.38)) and higher odds of scoring ≥ the 90^th percentile (OR: 1.98 (1.26, 3.11)). Maternal trans-DCCA above the detection level increased the odds of ADHD symptoms (OR: 1.76 (1.08, 2.86)). The associations were not modified by sex.

CONCLUSIONS

Prenatal exposure to pyrethroids was associated with ADHD related traits at 2-4 years of age. Considering the widespread use of pyrethroids these results are of concern.

Aldosterone, Salt, and Potassium Intakes as Predictors of Pregnancy Outcome, Including Preeclampsia

The mineralocorticoid aldosterone increases in plasma in healthy pregnancy along with renin and angiotensin II and plays a key role in the physiological plasma volume expansion. In mice, aldosterone contributes to an optimal fetal development by enhancing PlGF (placental growth factor) expression and trophoblast cell proliferation. In preeclampsia, there is coincident suppression of aldosterone and impaired placental development. We hypothesized that aldosterone independently contributes to placental and birth weight in humans, and high dietary sodium and low potassium intakes affect this relationship adversely. We analyzed 24-hour urine collections and plasma samples from gestational week 29 in a subsample of 569 pregnant women from the Odense Child Cohort-a Danish population-based longitudinal cohort study. Plasma and urinary aldosterone were measured by ELISA, sodium and potassium excretions by flame photometer. Predictive values of aldosterone levels and sodium and potassium intakes were assessed by multiple and Cox regression analyses. Primary outcomes were placental weight and birth weight. Secondary outcome was preeclampsia. Urinary aldosterone excretion at gestational week 29 independently contributed to placental and birth weights (adjusted β-coefficients [95% CI], 24.50 [9.66-39.35] and 9.59 [4.57-14.61], respectively). Aldosterone levels were not associated to preeclampsia incidence. Salt intake >6 g/d was associated with development of preeclampsia (hazard ratio [95% CI], 5.68 [1.51-21.36]). At gestational week 29, urinary aldosterone excretion is an independent predictor of placental and birth weights. High salt intake is a risk factor for preeclampsia. In perspective, suppression of aldosterone in pregnancy has adverse trophic effects.

Prenatal bisphenol A exposure is associated with language development but not with ADHD-related behavior in toddlers from the Odense Child Cohort

Bisphenol A (BPA) is a non-persistent chemical with endocrine disrupting abilities widely used in a variety of consumer products. The fetal brain is particularly sensitive to chemical exposures due to its rapid growth and complexity. Some studies have reported associationbetween maternal BPA exposure and behavior but few have assessed impact on cognitive development, and to our knowledge no studies have specifically assessed the impact on language development. We therefore assessed whether maternal urinary BPA concentration during pregnancy was associated with language development and attention-deficit and hyperactivity disorder (ADHD) symptoms in offspring aged 18-36 months in the prospective Odense Child Cohort. BPA was analyzed in 3rd trimester maternal fasting urine spot samples. Language development was addressed among 535 children using the Danish adaptation of the MacArthur-Bates Communicative Development Inventories at median age 21 months; ADHD traits were assessed by parents of 658 children using the Child Behavior Checklist for ages 1½-5 years at mean age 2.7 years. Associations were assessed using logistic regression models comparing children below the 15th percentile score for language and above the 85 percentiles score for ADHD with the other children while stratifying by sex and adjusting for maternal education, duration of breastfeeding and maternal urine phthalates. BPA was detected in 85.3% of the urine samples (median 1.2 ng/ml). Boys of mothers with BPA exposure in the highest tertile had an odds ratio of 3.70 (95% CI 1.34-10.21) of being in the lowest 15th percentile of vocabulary score compared to boys of mothers within the lowest tertile of BPA exposure after adjustment, whereas no association was found in girls. No clear dose-response relationship between maternal BPA and ADHD scores above the 85th percentile was found for either sex. Since early language development is a predictor of future reading skills and educational success, more epidemiological studies assessing BPA exposure and language skills are needed to confirm our findings.

Polycystic ovary syndrome and hyperglycaemia in pregnancy. A narrative review and results from a prospective Danish cohort study

BACKGROUND

Insulin resistance is common in polycystic ovary syndrome (PCOS). PCOS may be associated with increased risk of gestational diabetes mellitus (GDM).

OBJECTIVES

To (1) review literature regarding PCOS and hyperglycaemia in pregnancy and (2) present original data from Odense Child Cohort (OCC) regarding GDM in PCOS.

METHODS

Literature search including original studies from 2000-18. OCC included 2548 pregnant women, 9.5% (n = 241) had PCOS. Fasting plasma glucose was measured in 1519 and 659 oral glucose tolerance tests were performed (with risk factor for GDM, n = 384, without risk factors, n = 275), applying two different GDM criteria.

RESULTS

30 studies were eligible using 12 different sets of diagnostic criteria for GDM. Ten studies included n > 50, control group, assessment of GDM and BMI. Results were not uniform, but supported that higher BMI, higher age, Asian ethnicity, and fertility treatment increased the risk of GDM in PCOS. In OCC, women with PCOS and controls had similar prevalences of GDM independent of different sets of criteria for GDM.

CONCLUSION

PCOS may not be an individual risk factor for GDM. Pregnancies in PCOS are characterized by factors known to increase risk of GDM, especially high BMI and fertility treatment.

Testosterone Levels in Third Trimester in Polycystic Ovary Syndrome: Odense Child Cohort

BACKGROUND

Polycystic ovary syndrome (PCOS) is characterized by hyperandrogenism. In pregnancy, testosterone levels may be higher in women with PCOS compared with controls.

AIMS

To compare total testosterone (TT), free testosterone (FT), and sex hormone-binding globulin (SHBG) levels in third-trimester pregnant women with PCOS and controls and to establish reference ranges for TT, FT, and SHBG in PCOS and controls.

METHODS

The study was part of the prospective study, Odense Child Cohort. PCOS was diagnosed by questionnaires and/or patient records. Fasting blood samples were collected at gestational week 28 and plasma TT was measured by liquid chromatography-tandem mass spectrometry in women with PCOS (n = 145) and in women without PCOS (controls, n = 1341).

RESULTS

Levels of TT (mean, 2.4 vs 2.0 nmol/L) and FT (mean, 0.005 vs 0.004 nmol/L) were higher, whereas SHBG levels (mean, 447 vs 477 nmol/L) were lower in women with PCOS vs controls (all P < 0.001). Reference intervals for TT, FT, and SHBG in women with PCOS and controls were overlapping, and partitioning of reference intervals was an ambiguous decision. In multiple regression analyses, TT and FT levels were positively associated with PCOS status and BMI and inversely associated with age and parity. Offspring sex did not predict maternal TT and FT.

CONCLUSIONS

TT and FT levels were higher in third-trimester pregnant women with PCOS compared with controls. Separate reference interval for FT in women with PCOS should be considered.

Perfluoroalkyl substances and glycemic status in pregnant Danish women: The Odense Child Cohort

BACKGROUND

Perfluoroalkyl substances (PFASs) are persistent chemicals with suspected endocrine disrupting abilities applied in consumer products. PFASs have potentially modulating effects on glucose homeostasis. Insulin resistance prevails during third trimester of pregnancy, and this challenge of glucose homeostasis may reveal putative effects of PFAS concentrations on glycemic status.

OBJECTIVE

To investigate associations between five serum PFASs and glucose-related outcomes in pregnant Danish women based on their risk of gestational diabetes mellitus (GDM).

METHODS

In the prospective Odense Child Cohort serum concentrations of five PFASs - perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) - were measured at median gestational week (GW) 11 in pregnant women. An oral glucose tolerance test (OGTT) was performed at GW 28. The statistical analysis was conducted among 158 women with high GDM risk and 160 women with low GDM risk matched by gestational age. Multiple linear regression models were performed to estimate associations between PFAS concentrations and glucose, insulin, C-peptide, homeostatic model of assessment of insulin resistance (HOMA-IR) and beta cell function (HOMA-%β), and insulin sensitivity (Matsuda index) during the 2-h OGTT.

RESULTS

In women with high risk for GDM, a two-fold increase in PFHxS concentration was significantly associated with increased fasting glucose, fasting insulin and HOMA-IR after adjusting for age, parity, educational level and pre-pregnancy BMI. Adjusting for the same confounders, a doubling in PFNA concentration was associated with higher fasting insulin and HOMA-%β. In women with low GDM risk, no associations were found between PFAS concentrations and glucose-related outcomes.

CONCLUSION

PFHxS and PFNA concentrations were associated with impaired glycemic status in metabolically vulnerable pregnant women and might further enhance the risk of developing GDM.

A novel inverse association between cord 25-hydroxyvitamin D and leg length in boys up to three years. An Odense Child Cohort study

Background and aim

Long standing vitamin D deficiency in children causes rickets with growth impairment. We investigated whether sub-ischial leg length (SLL) is shorter, and cephalo-caudal length:length (CCL:L) ratio and sitting height:height (SH:H) ratio larger, with lower cord s-25-hydroxyvitamin D (25OHD) in the population-based prospective Odense Child Cohort, Denmark.

Methods

We included healthy singletons born to term with available measures of cord 25OHD and anthropometrics up to three years’ age. Linear regression was stratified by sex a priori and adjusted for maternal ethnicity, pre-pregnancy body mass index and smoking during pregnancy, season of blood sampling and child age.

Results

Median (IQR) cord 25OHD was 48.0 (34.0–62.4) nmol/L. At mean age 19.1 months, n = 504, mean (SD) SLL was 31.7 (1.7) cm; CCL:L-ratio 0.62 (0.01). At 36.3 months, n = 956, mean SLL was 42.9 (2.0) cm; SH:H-ratio 0.56 (0.01). No participants had rickets. In adjusted analyses, 19-months-old boys had 0.1 cm shorter SLL (p = 0.009) and 0.1% higher CCL:L-ratio (p = 0.04) with every 10 nmol/L increase in cord 25OHD. Similar findings were seen for late pregnancy 25OHD. In the highest cord 25OHD quartile (>60.7 nmol/L), SLL was 0.8 cm shorter (95% C.I.: 1.36;-0.29, linear trend, p = 0.004), and CCL:L-ratio 0.8% higher (95% C.I. 8.0x10^-05;0.01, linear trend, p = 0.01), compared to lowest quartile (<30.7 nmol/L). Similar associations with cord 25OHD were observed in 3-year-old boys. No consistent associations between 25OHD and anthropometrics were seen in girls at either age.

Conclusion

No leg shortening was found with decreasing cord s-25OHD in a healthy population of infants. A small, yet significant inverse association between cord 25OHD and SLL in boys 1½-3 years warrants further investigations.

Prenatal phthalate exposure and language development in toddlers from the Odense Child Cohort

BACKGROUND

Phthalates are a group of chemicals found in a variety of consumer products. They have anti-androgenic properties and human studies have reported associations between prenatal phthalate exposure and neuropsychological development in the offspring despite different cognitive tests, different ages and varying timing of exposure.

OBJECTIVES

To investigate the association between prenatal phthalate exposure and language development in children aged 20-36months.

METHODS

In the Odense Child Cohort, we analyzed 3rd trimester urine samples of 518 pregnant women for content of metabolites of diethyl, di-n-butyl, diisobutyl, butylbenzyl, di(2-ethylhexyl), and diisononyl phthalate, adjusted for osmolality. Language development was addressed using the Danish version of the MacArthur-Bates Communicative Development Inventories "Words and Sentences". Associations were assessed using logistic regression models comparing children below and above the 15th percentile while stratifying by sex and adjusting for maternal age and educational level.

RESULTS

Phthalate metabolites were detectable in all samples although in lower levels than previous studies. Among boys, increased prenatal phthalate exposure was associated with lower scores in language development; odds ratios for vocabulary score below the 15th percentile with doubling in monoethyl phthalate, and summed di-(2-ethylhexyl) phthalate metabolites were respectively 1.24 (95% confidence interval: 1.05,1.46), and 1.33 (1.01,1.75). Similar associations were found for language complexity. No associations were found for girls.

CONCLUSIONS

Our findings are notable, as adverse associations were suggested even in this low-level exposed population, with only one spot urine sample for exposure assessment and control for confounders. Lower scores in early language development are of relevance to health as this test predicts later educational success.

Prenatal exposure to antifungal medication may change anogenital distance in male offspring: a preliminary study

BACKGROUND

Vaginal candidiasis is frequent among pregnant women and it is treated with anti-fungal medication (conazoles). Conazoles have anti-androgenic properties and prenatal exposure in rodents is associated with a shorter (less masculine) anogenital distance (AGD) in male offspring. To our knowledge this has never been studied in humans.

METHOD

In the Odense Child Cohort pregnant women residing in Odense municipality, Denmark, were recruited at gestational age 8-16 weeks between 2010 and 2012. Of the eligible 2421 mother-child pairs, 812 mother-son pairs were included. Questionnaire data on medicine use were collected in first and third trimester and physical examination at age 3 month was performed. Ano-scrotal distance; measured from the centre of anus to the posterior base of scrotum (AGDas). Ano-cephalad distance; measured from the centre of anus to the cephalad insertion of the penis (AGDap) and penile width; measured at the base of the penis.

RESULTS

Eighty seven women had used antifungal medicine during pregnancy. Maternal use of oral fluconazole (n = 4) was associated with a 6.4 mm shorter AGDas (95% CI: -11.9;-0.9) in the male offspring. Use of antifungal vaginal tablets (n = 21), was associated with a non-significantly shorter AGDas (-1.9 mm; 95% CI: -4.3; 0.5) whereas exposure to vaginal cream (n = 23) was not associated to AGDas. Use of antifungal medicine in the window of genital development between 8 and 14 weeks of gestation was associated with a larger reduction in AGDas than exposure outside this window. Antifungal medicine intake was not associated with AGDap and penil width.

CONCLUSION

Our preliminary findings prompted us to hypothesize that maternal use of conazole antifungal medication during pregnancy may affect the masculinization of male offspring. If confirmed, pregnant women should be advised to use antifungal medicine with caution.

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 perfluoroalkyl substances and anogenital distance at 3 months of age as marker of endocrine disruption

In the Odense child cohort, serum concentrations of perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) were measured in 649 pregnant women at approximately 12 weeks of gestation. Birth weight, head and abdominal circumferences were measured, and gestational age determined. Anogenital distance (AGD), i.e., the distance from the anus to the genital organs, penile width and body weight were measured 3 months after the expected date of birth in 511 children. PFOS, PFHxS, PFNA and PFDA were associated with a decreased AGD in girls (p-trend<0.05) after adjusting for age and weight-for-age standard deviation score. Specifically, PFOS in the highest quartile was associated with a 2.8mm (95% confidence intervals -4.5;-1.1) reduction in AGD in girls. No such tendencies were seen in boys. However, a tendency toward increased birth weight in girls and reduced in boys suggests that sex-dimorphic effects may occur from endocrine disrupting effects of these substances.

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.

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.

Association between perfluorinated compound exposure and miscarriage in Danish pregnant women

Perfluorinated alkylated substances (PFAS) have been extensively used in consumer products and humans are widely exposed to these persistent compounds. A recent study found no association between exposure to perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) and miscarriage, but no studies have examined adverse effect of the more recently introduced PFASs. We therefore conducted a case-control study within a population-based, prospective cohort during 2010-2012. Newly pregnant women residing in the Municipality of Odense, Denmark were invited to enroll in the Odense Child Cohort at their first antenatal visit before pregnancy week 12. Among a total of 2,874 participating women, 88 suffered a miscarriage and 59 had stored serum samples, of which 56 occurred before gestational week 12. They were compared to a random sample (N=336) of delivering women, who had also donated serum samples before week 12. Using a case-control design, 51 of the women suffering a miscarriage were matched on parity and gestational day of serum sampling with 204 delivering women. In a multiple logistic regression with adjustment for age, BMI, parity and gestational age at serum sampling, women with the highest tertile of exposure to perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) in pregnancy had odds ratios for miscarriage of 16.5 (95% CI 7.4-36.6-36.5) and 2.67 (1.31-5.44), respectively, as compared to the lowest tertile. In the matched data set, the OR were 37.9 (9.9-145.2) and 3.71 (1.60-8.60), respectively. The association with perfluorohexane sulfonic acid (PFHxS) was in the same direction, but not statistically significant, while no association was found with PFOA and PFOS. Our findings require confirmation due to the possible public health importance, given that all pregnant women are exposed to these widely used compounds.

Polybrominated diphenyl ethers and perfluoroalkyl substances in serum of pregnant women: levels, correlations, and potential health implications

Polybrominated diphenyl ethers (PBDEs), a group of flame retardants, and perfluoroalkyl substances (PFASs) were analysed in serum samples of pregnant women from Denmark to provide information about their exposure and to study indications of common exposure pathways. The main BDE congener was the fully brominated BDE-209 with a median value of 7.5 ng/g lipid (46 pg/mL; 9.8 pmol/g lipid). Other BDE congeners decreased in the order BDE-47 > BDE-99 > BDE-153. The summed concentration of tri- to hepta-BDEs was 7.7 ng/g lipid, i.e. in the higher end of previously reported concentrations from Europe, including plasma samples of pregnant Danish women. Total lipid contents were relatively low, on average 5.9 g/L (9.0 mmol/L). The main PFAS compound was perfluorooctane sulfonate with a median concentration of 8.4 ng/mL. Other PFASs decreased in the order perfluorooctanoic acid > perfluorononanoic acid > perfluorodecanoic acid > perfluorohexane sulfonate and resulted in a ΣPFAS of 12 ng/mL. Within each group, compounds were highly intercorrelated with the exception of BDE-209, which was not correlated with any of the other compounds. No correlations were found either between PFASs and PBDEs suggesting different sources of exposure and/or pharmacokinetic and metabolisation processes. PBDE and PFAS concentrations were in the range associated with adverse effects in some epidemiological studies.

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.

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.

Parity and tanned white skin as novel predictors of vitamin D status in early pregnancy: a population-based cohort study

CONTEXT

In pregnancy, vitamin D insufficiency and deficiency, defined as serum 25-hydroxyvitamin D (25(OH)D) <50 nM, and <25 nM, respectively, may have adverse effects for both mother and child. Prevalence estimates, and identification of subgroups at special risk, may be useful for the planning of preventive strategies.

OBJECTIVE

To study the prevalence and risk factors of hypovitaminosis D in early pregnancy.

DESIGN AND METHODS

In a cross-sectional study of 1348 women in early pregnancy from the Odense Child Cohort, Denmark, 25(OH)D was determined and correlated to demographic and lifestyle variables (age, nationality, skin tone, parity, prepregnancy body mass index (BMI), smoking and sun exposure), using multiple linear and logistic regression analyses for all year, or stratified for summer and winter. The risk of vitamin D insufficiency was expressed as odds ratios (OR) with 95% confidence intervals in brackets.

RESULTS

The prevalence of vitamin D insufficiency and deficiency was estimated to 27·8% and 3·5% respectively. In adjusted analyses, vitamin D insufficiency was directly associated with winter season, OR = 1·89 (1·35-2·63); increasing prepregnancy BMI, OR = 1·06 (1·03-1·10); and smoking, OR = 2·7 (1·34-5·41); but was less frequent in nulliparous, OR = 0·47 (0·33-0·68) and tanned Caucasians, OR = 0·63 (0·41-0·97). Season-specific associations having parental origin from outside Europe in summer, OR = 4·13 (1·41-12·13); in winter smoking, OR = 3·15 (1·19-8·36); and prepregnancy BMI, OR = 1·12 (1·06-1·18).

CONCLUSIONS

Vitamin D insufficiency was widespread in early pregnancy. Associations to smoking, prepregnancy BMI and origin outside Europe varied with season. Multiparity and not being tanned in Caucasians represent new risk factors of vitamin D insufficiency.

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.