Early-life exposure to perfluoroalkyl substances and serum antibody concentrations towards common childhood vaccines in 18-month-old children in the Odense Child Cohort.

Exposure to per- and polyfluoroalkyl substances (PFAS) has been associated with reduced antibody response to childhood vaccinations. Previous studies have mostly focused on antibodies against diphtheria or tetanus, while fewer studies have assessed antibodies toward attenuated viruses, such as measles, mumps or rubella (MMR). Therefore, we set out to determine associations between prenatal and early postnatal PFAS exposure and vaccine-specific Immunoglobulin G (IgG) in the background-exposed Odense Child Cohort. Blood samples were drawn in pregnancy at gestation weeks 8-16 and from the offspring at age 18 months. In the maternal serum samples we quantified perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA). In the offspring serum samples we quantified the same five PFAS compounds and IgG towards diphtheria, tetanus and MMR. A total of 880 and 841 children were included in the analyses of diphtheria and tetanus or MMR, respectively. Multiple linear regression models were used for estimation of difference in virus-specific IgG per doubling of PFAS concentrations. Maternal PFAS concentrations were non-significantly inversely associated with most vaccine-specific antibody concentrations. Likewise, child PFAS concentrations were associated with non-significant reductions of antibodies towards tetanus and MMR. A significant reduction in the percent difference in mumps antibody concentration per doubling of child PFNA (-9.2% (95% confidence interval: -17.4;-0.2)), PFHxS (-8.3% (-15.0;-1.0) and PFOS (-7.9% (-14.8;-0.4) was found. These findings are of public health concern, as inadequate response towards childhood vaccines may represent a more general immune dysfunction.

Maternal cortisol levels in third trimester and early language development: A study of 1093 mother-child pairs from the Odense Child Cohort.

Language development during early childhood is considered an important marker of fetal neurodevelopment. Prenatal cortisol exposure plays a critical role in maturation of the fetal brain; however, the effect on offspring language development needs further investigation. In this prospective observational study we aimed to evaluate the association between maternal third trimester cortisol and early longitudinal offspring language development in the Odense Child Cohort (OCC) and to test whether there were sex differences in the association. The study cohort included 1093 mother-child dyads (570 boys and 523 girls). Fasting morning serum (s-) cortisol was collected from third trimester (gestational week 26-28) pregnant women and measured by liquid chromatography-tandem mass spectrometry. Offspring receptive and productive vocabulary assessments by MacArthur-Bates Communicative Development Inventories parent reports were completed every third month from children age 12-37 months. Levels of cortisol were higher in women carrying a girl (858 ± 214 nmol/L) than in women carrying a boy (820 ± 222 nmol/L). Higher third trimester maternal cortisol levels showed a positive association with development of productive vocabulary in boys at age 12-21 months (OR = 1.23, SE = 0.07, p = .005) and age 22-37 months (OR = 1.09, SE = 0.06, p = .967). Higher maternal cortisol levels in the third trimester were positively associated with receptive vocabulary in girls at 12-21 months of age (OR = 1.16, SE = 0.05, p = .002). Maternal third trimester s-cortisol levels were positively associated with early language development in children at age 12-37 months.

Maternal cortisol in 3rd trimester is associated with traits of neurodevelopmental disorder in offspring. Odense Child Cohort.

BACKGROUND: Prenatal cortisol exposure is essential for neurodevelopment. Maternal cortisol levels could be associated with offspring autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD). AIM: To investigate associations between maternal 3rd trimester cortisol and offspring traits of ASD and ADHD. MATERIAL AND METHODS: Mother-child pairs were included from the prospective study Odense Child Cohort. Morning serum cortisol and 24-hour urine cortisol/cortisone were collected at gestational week 27-30. Offspring ASD and ADHD traits were assessed at age three and five years using the Child Behavior Checklist. Maternal cortisol measurements and offspring ASD and ADHD traits assessment were available in (n = 1131; 52% boys) mother-child pairs at age three and (n = 717; 54% boys) at five years of age. Maternal 24-hour urine measurement was available in a subset, at offspring three years of age (n = 300) and at five years of age (n = 217). Associations between maternal cortisol (continuous and tertiles) and offspring ASD or ADHD traits were examined in regression models adjusted for offspring sex, maternal age, pre-pregnancy BMI, parity, maternal education level, parental psychiatric disorders, and maternal smoking and stratified for offspring sex. RESULTS: Maternal mean age ( ± SD) was 30 years ( ± 4.4) and median BMI (25%; 75% percentiles) 23.5 kg/m2 (21.3; 26.6). Higher maternal serum cortisol levels were associated with higher prevalence of offspring ASD traits at three years of age in the total study cohort and in boys after stratifying for offspring sex. In the total population, tertiles of serum cortisol showed a significant dose-response relationship to ASD traits in unadjusted and adjusted models (p-values for linear trend, p < 0.01 and p = 0.02, respectively). In offspring at five years, associations between maternal cortisol and offspring ASD traits were non-significant (all p-values > 0.2). Maternal cortisol was not associated with offspring ADHD traits (all p-values > 0.07) in offspring at three and five years. Maternal 24-hour urine cortisol, cortisone, or cortisol/cortisone ratio were not associated with offspring ASD or ADHD traits. CONCLUSION: Higher maternal serum cortisol in 3rd trimester was associated with offspring ASD traits at three years of age in the whole study cohort and in boys, but not in girls. This association was non-significant at five years of age.

Prenatal and current phthalate exposure and cognitive development in 7-year-old children from the Odense child cohort.

BACKGROUND: Phthalates are endocrine disrupters used in a variety of consumer products. Human studies suggest an association between phthalate exposure and cognitive development but adverse effects of the recently introduced phthalate substitutes have only been sparsely studied. OBJECTIVES: To investigate associations between prenatal and concurrent exposure to phthalates and IQ in 7-year-old children from the Odense Child Cohort. METHODS: Pregnant women from the Odense Child Cohort had phthalate metabolites measured in urine samples during 3rd trimester in 2010 to 2012. In addition, phthalates were also measured in urine samples from their offspring at age 7 years. IQ was assessed at age 7 years using four subtests from Wechsler Intelligence Scale for Children. The total study population consisted of 585 mother-child pairs with available prenatal urinary phthalate metabolites concentrations and IQ data at age 7 years. A subset of those (N = 274) had urinary phthalate metabolites measured in child urine at age 7 years. Phthalate concentrations were grouped into tertiles and associations with IQ were investigated using multiple linear regression adjusting for sex, maternal education and maternal/child BMI. RESULTS: Urinary phthalate metabolite concentrations both in pregnant women and children were generally lower compared to previous cohorts. Children with high prenatal urinary concentrations of MEP and metabolites of DEHP (∑DEHPm)(3rd tertile) had -3.1 (95% CI: -5.5, -0.6) (MEP) and - 3.0 (-5.5, -0.6) (∑DEHPm) IQ points at age 7 years compared to children with low concentrations (1st tertile). High concurrent urinary phthalate concentrations of MCPP, ∑DnHxPm, ∑DiDPm and ∑DiNPm in the 3rd tertile was associated with -3.7 (-7.2, -0.2), -4.4 (-7.9, -0.9), -3.7 (-7.2, -0.2) and - 5.6 (-9.1, -2.2) IQ points, respectively, compared to those with the lowest concentrations (1st tertile). CONCLUSION: We found significant inverse associations between some prenatal and concurrent urinary phthalate concentrations and IQ at age 7 years in this low exposed population. This suggests that exposure to phthalates both prenatally and during early childhood could be hazardous to child neurodevelopment, however, large-scale prospective studies assessing phthalate exposure through multiple urine samples, and possibly investigating cocktail effects of the chemicals as well as long term follow-up are warranted.

Parental Recreational Screen Media Practices and Behavioral Difficulties Among Danish 7-Year-Old Children.

OBJECTIVE: This study aimed to investigate the association of parental recreational screen media practices, including time use and level of smartphone addiction, with behavioral difficulties in 7-year-old children. METHODS: The study was based on cross-sectional data from the Odense Child Cohort, a community-based birth-cohort study. A total of 1152 parent-child dyads with complete data were included based on data from the 7-year examination conducted in 2018-21. Parental recreational screen use was self-reported as hours/day using the SCREENS-questionnaire, and their smartphone addiction was self-reported using the Smartphone Addiction Scale Short Version. Child behavioral difficulties were assessed by the parent-reported version of the Strengths and Difficulties Questionnaire (SDQ). RESULTS: Parental recreational screen time was not consistently associated with behavioral difficulty SDQ subscales and total difficulty scores when adjusted for other determinants of child mental well-being such as sociodemographic factors, parental well-being, and number of siblings. Children had higher total behavioral difficulty scores (adjusted mean difference 2.12 (95% CI, 1.19-3.05)) when comparing fourth quartile versus first quartile of maternal smartphone addiction score. Also, higher maternal smartphone addiction scores were associated with more externalizing and internalizing behavioral problems of their child (adjusted mean difference 1.61 points (95% CI, 0.95-2.27), and 0.81 points (95% CI, 0.19-1.43)) for fourth quartile versus first quartile, respectively. CONCLUSIONS: No cross-sectional association was found between total parental recreational screen use and behavioral difficulties in their 7-year-old children, but an association between maternal obsessive smartphone use and behavioral difficulties of their children was found.

Prenatal paraben exposures and birth size: Sex-specific associations in a healthy population - A study from the Odense Child Cohort.

OBJECTIVES: To investigate the sex-specific associations between maternal paraben concentrations in second trimester urine and birth size of the offspring. METHODS: A prospective cohort study of 529 mother-child pairs within the Odense Child Cohort. Pregnant women were recruited to the cohort from 2010 to 2012 and provided fasting spot urine samples in second trimester (median 28.7 weeks). Concentrations of methylparaben (MeP), ethylparaben (EtP), iso-propylparaben (i-PrP), n-propylparaben (n-PrP), n-butylparaben (n-BuP) and benzylparaben (BzP) were analyzed by isotope diluted liquid-chromatography tandem-mass-spectrometry and osmolality adjusted. Exposures were categorized into tertiles or above/below level of detection. Data on maternal and birth characteristics were extracted from hospital records. Sex-stratified multiple linear regression analyses were performed according to relevant birth outcomes (length, weight, head/abdominal circumference) adjusting for a priori defined confounders. RESULTS: Higher paraben levels were detected in pregnant women who were older, more obese, who smoked and were primigravidae. Generally, higher maternal paraben exposure was consistently associated with lower birth size in female but not in male offspring, but with few substantial or statistically significant. Higher maternal exposure to n-BuP during pregnancy was associated with a statistically significant lower birth size in female offspring only [birth weight: -137 g (95 % CI -256; -19), head circumference: -0.48 cm (95 % CI -0.90; -0.05), abdominal circumference: -0.65 cm (95 % CI -1.21; -0.08)]. No differences in birth size were observed for other parabens. CONCLUSION: Higher maternal exposure to n-butylparaben was associated with lower birth size in female but not male offspring.

Prenatal and early childhood predictors of intelligence quotient (IQ) in 7-year-old Danish children from the Odense Child Cohort.

BACKGROUND: Cognitive development measured as intelligence quotient can predict socioeconomic markers in adulthood. It is therefore of interest to determine predictors of childhood intelligence quotient. AIM: To assess intelligence quotient scores based on standardised Danish age-appropriate scores and to evaluate potential predictors of intelligence quotient. MATERIALS: At 7 years of age children in the Odense Child Cohort completed an abbreviated version of the Wechsler intelligence scale for children 5th edition consisting of four subtests (vocabulary, similarities, block design and matrix reasoning) from which the full scale intelligence quotient and verbal comprehension index were estimated. Potential predictors from pregnancy through childhood were collected from questionnaires, birth records and clinical examinations. METHODS: Intelligence quotient scores were investigated through descriptive statistics and linear regression models. RESULTS: The mean full scale intelligence quotient among 1375 children was 99.1 (95% confidence interval 98.5; 99.8) points. Higher full scale intelligence quotient scores were observed in girls 100.8 (95% confidence interval 100.0; 101.8) compared to boys 97.6 (96.7; 98.4), and in children of mothers with high and intermediate education 101.7 (100.4; 103.1) and 99.6 (98.7; 100.5), respectively, compared to low education 96.1 (94.9; 97.3). In linear regression analyses, longer maternal education and child sex (girls) remained strong predictors of intelligence quotient at age 7 years. In addition, paternal education, child head circumference and longer duration of breastfeeding were associated with higher intelligence quotient, whereas maternal overweight and obesity before pregnancy was associated with lower intelligence quotient. CONCLUSIONS: Mean intelligence quotient scores were comparable to the standardised mean intelligence quotient of 100 point of Danish peers. It is important to follow up these children to determine which predictors persist into adulthood.

Prenatal Androgen Exposure and Traits of Autism Spectrum Disorder in the Offspring: Odense Child Cohort.

Fetal androgen exposure may be associated with autism spectrum disorder (ASD). We studied 1777 mother-child pairs in the prospective Odense Child Cohort. Prenatal androgen exposure was assessed by maternal 3rd trimester testosterone concentrations, maternal polycystic ovary syndrome (PCOS), and 3 months offspring anogenital distance. ASD traits were assessed at age 3 years with the ASD-symptom scale of the Child Behavior Checklist for ages 1½-5 years. Maternal testosterone was positively associated with traits of ASD in boys (p < 0.05). Maternal PCOS was associated with increased offspring ASD traits (p = 0.046), but became non-significant after excluding parental psychiatric diagnosis. Offspring anogenital distance was not linked to ASD traits. Higher prevalence of ASD in boys could be linked to higher susceptibility to fetal androgen exposure.

Mixture Risk Assessment of Complex Real-Life Mixtures-The PANORAMIX Project.

Humans are involuntarily exposed to hundreds of chemicals that either contaminate our environment and food or are added intentionally to our daily products. These complex mixtures of chemicals may pose a risk to human health. One of the goals of the European Union's Green Deal and zero-pollution ambition for a toxic-free environment is to tackle the existent gaps in chemical mixture risk assessment by providing scientific grounds that support the implementation of adequate regulatory measures within the EU. We suggest dealing with this challenge by: (1) characterising 'real-life' chemical mixtures and determining to what extent they are transferred from the environment to humans via food and water, and from the mother to the foetus; (2) establishing a high-throughput whole-mixture-based in vitro strategy for screening of real-life complex mixtures of organic chemicals extracted from humans using integrated chemical profiling (suspect screening) together with effect-directed analysis; (3) evaluating which human blood levels of chemical mixtures might be of concern for children's development; and (4) developing a web-based, ready-to-use interface that integrates hazard and exposure data to enable component-based mixture risk estimation. These concepts form the basis of the Green Deal project PANORAMIX, whose ultimate goal is to progress mixture risk assessment of chemicals.

Higher free thyroxine associated with PFAS exposure in first trimester. The Odense Child Cohort.

BACKGROUND: Perfluoroalkyl substances (PFAS) are endocrine disrupting chemicals with elimination half-lives ranging from four to eight years. Experimental studies found PFAS able to interfere with thyroid hormone-binding proteins. During the first 20 weeks of gestation (GW), the fetus is reliant on placental transfer of maternal thyroid hormones, mainly free thyroxine (FT4). However, previous studies investigating associations between exposure to PFAS and thyroid hormone status mainly focused on blood samples from late pregnancy or umbilical cord with mixed findings. OBJECTIVES: To investigate associations between serum-PFAS concentrations and thyroid hormone status in early pregnancy as reflected by FT4 and thyroid-stimulating hormone (TSH). METHODS: In the Odense Child Cohort, a single-center study, we measured maternal pregnancy serum concentrations of five PFAS: perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA); and FT4 and TSH in 1048 pregnant women at median GW 12 (25th, 75th percentile: 10, 15). Multivariate linear regression models were performed to estimate associations between PFAS exposure and thyroid hormone status. RESULTS: A doubling in PFOS, PFOA, and PFNA concentrations was associated with an increment in FT4 concentration by 1.85% (95% CI: 0.66%, 3.05%), 1.29% (95% CI: 0.21%, 2.39%), and 1.70% (95% CI: 0.48%, 2.94%), respectively, in adjusted analyses. A statistically significant dose-response relationship was observed across exposure quartiles for PFOS, PFOA, and PFNA in the association with FT4. No association was found between concentrations of PFAS and TSH in adjusted analyses. CONCLUSION: Exposure to PFOS, PFOA, and PFNA was associated with higher FT4 concentrations in women during early pregnancy. The potential clinical implications of these findings remain to be clarified.

Pregnancy Exposure to Perfluoroalkyl Substances and Associations With Prolactin Concentrations and Breastfeeding in the Odense Child Cohort.

CONTEXT: Human exposure to perfluoroalkyl substances (PFAS) has been associated with reduced duration of breastfeeding, although not consistently so, and mechanisms by which PFAS might affect breastfeeding are unknown. OBJECTIVE: To examine the association between early pregnancy serum-PFAS concentrations and breastfeeding termination and to elucidate the potential role of serum-prolactin concentrations in pregnancy. MATERIALS AND METHODS: Pregnant women from the Odense Child Cohort provided blood samples for analysis of 5 major PFAS (n = 1300) and prolactin concentrations (n = 924). They subsequently provided information about the duration of breastfeeding in questionnaires at 3 and 18 months postpartum, and a subgroup also provided breastfeeding information via weekly cell phone text messages. Associations between serum-PFAS concentrations and breastfeeding termination were analyzed using Cox regressions, while linear regression was used to assess associations between serum-PFAS and prolactin concentrations. RESULTS: Increased serum concentrations of perfluorooctane sulfonic acid, perfluorooctanoic acid, perfluorononanoic acid, and ∑PFAS were associated with a 16% (95% CI: 4%-30%), 14% (95% CI: 2%-26%), 14% (95% CI: 3%-27%), and 20% (95% CI: 6%-36%), respectively, increased risk of terminating breastfeeding at any given time after childbirth. Serum-PFAS concentrations were not associated with serum-prolactin concentrations. CONCLUSIONS: These findings are of public health importance due to the global exposures to PFAS. Because breastfeeding is crucial to promote both child health and maternal health, adverse PFAS effects on the ability to breastfeed may have long-term health consequences.

Pregnancy exposure to bisphenol A and duration of breastfeeding.

INTRODUCTION: Bisphenol A (BPA) is frequently used in the production of plastics. It is an endocrine disruptor, and BPA exposure in mice has been associated with reduced offspring growth due to insufficient milk production. However, human studies of associations between BPA exposure and duration of breastfeeding are sparse. METHODS: Pregnant women from the Odense Child Cohort (n = 725) donated a third trimester morning urine sample, which was analyzed for BPA by LC-MS/MS. Information about duration of exclusive and any breastfeeding was obtained through questionnaires three and 18 months postpartum, and a subgroup of women responded to weekly text messages about breastfeeding. Associations between pregnancy BPA exposure and duration of breastfeeding were analyzed using Cox regression adjusting for potential confounders. RESULTS: The median urine BPA concentration was 1.29 ng/mL. Compared to women within the lowest tertile of BPA exposure, women in the second and third tertile were slightly more likely to terminate breastfeeding at any given time; HRs (95% CI) were 1.05 (0.87; 1.26) and 1.06 (0.89; 1.27), respectively, and to terminate exclusive breastfeeding at any time up to 20 weeks after birth, HRs (95% CI) were 1.07 (0.88; 1.28) and 1.06 (0.88; 1.27), respectively. However, confidence intervals were also compatible with no effect or even a protective effect. DISCUSSION: This study indicated that high BPA exposure in pregnancy was associated with shorter duration of breastfeeding. Although our findings were not statistically significant, all estimates were above one suggesting increased risk of early breastfeeding termination with high exposure. Using a single spot morning urine sample to measure BPA has likely caused imprecision as it might not adequately reflect long term exposure. Future studies should consider measuring BPA more than once, including other timepoints during pregnancy and after birth.

Health anxiety symptoms in Danish children during the first lockdown period of the COVID-19 pandemic: an Odense Child Cohort study.

PURPOSE: The coronavirus disease 2019 (COVID-19) pandemic has a severe impact on the general population. During the pandemic, children may develop emotional and psychological symptoms, including increased worries about health and illness, known as health anxiety symptoms (HASs). We aimed to explore HAS in 7-9-year-old children from the Danish Odense Child Cohort (OCC) during the first COVID-19 lockdown period in Denmark, and to examine associations with potential risk factors. MATERIAL AND METHODS: OCC is a cohort of children born between 2010 and 2012, which originally recruited 2874 of 6707 pregnancies (43%). Among the current OCC population of 2430 singleton children, 994 participated in this study (response rate 40%). Children and their parents filled out questionnaires about child HAS, family exposure to COVID-19 infection and parental HAS. Adjusted odds ratios (aORs) were calculated between high score child HAS (≥90th percentile) and covariates by use of logistic regression. RESULTS: Most children (n = 686, 69%) reported few worries about their health. Children reporting high score HAS also had higher levels of internalizing symptoms at age 5; aOR 2.15 (1.20;3.85), p = .010, and higher levels of maternal and paternal HAS; aOR 2.40 (1.44;3.97), p = .001, and 2.00 (1.10;3.65), p = .023, whereas no association with child sex or familial exposure to COVID-19 was detected (n = 65, 6.5%). CONCLUSIONS: High score child HAS during the first lockdown period of the COVID-19 pandemic was not associated with family exposure to COVID-19 infection, but to being a more anxious child a priori and to HAS in parents.

Maternal polycystic ovary syndrome and attention deficit hyperactivity disorder in offspring at 3 years of age: Odense Child Cohort.

INTRODUCTION: Previous data suggested a link between maternal polycystic ovary syndrome (PCOS) and offspring attention deficit hyperactivity disorder (ADHD), which could be mediated by higher prenatal androgen exposure. MATERIAL AND METHODS: The study was part of the prospective Odense Child Cohort and included 1776 pregnant women, 165 (9%) with PCOS and 1607 (91%) controls. ADHD symptoms at 3 years of age were defined using the parent-reported questionnaire Child Behavior Checklist/1.5-5 (scores >90th centile of Danish national standard). Maternal blood samples were collected in the third trimester measuring total testosterone by mass spectrometry, sex hormone-binding globulin, and calculated free testosterone. Offspring anogenital distance was measured at 3 months of age. Regression models were performed with presence of ADHD symptoms as the dependent variable and adjusted for maternal age, body mass index, parity, smoking status, educational level, and parental psychiatric diagnoses. RESULTS: ADHD symptoms were present in 105/937 (11%) boys and 72/839 (9%) girls. In boys, maternal PCOS was positively associated with ADHD symptoms (unadjusted odds ratio [OR] 1.91, 95% CI 1.07-3.43, p = 0.03, adjusted OR 2.20, 95% CI 1.20-4.02, p = 0.01), whereas maternal PCOS was not associated with ADHD symptoms in girls. Maternal total testosterone, free testosterone, and offspring anogenital distance were not associated with higher risk of ADHD symptoms in the offspring. CONCLUSIONS: Higher risk of ADHD in boys born of mothers with PCOS were not associated with maternal third-trimester testosterone levels or offspring anogenital distance.