Male Reproductive Disorders and Fertility Trends: Influences of Environment and Genetic Susceptibility.

It is predicted that Japan and European Union will soon experience appreciable decreases in their populations due to persistently low total fertility rates (TFR) below replacement level (2.1 child per woman). In the United States, where TFR has also declined, there are ethnic differences. Caucasians have rates below replacement, while TFRs among African-Americans and Hispanics are higher. We review possible links between TFR and trends in a range of male reproductive problems, including testicular cancer, disorders of sex development, cryptorchidism, hypospadias, low testosterone levels, poor semen quality, childlessness, changed sex ratio, and increasing demand for assisted reproductive techniques. We present evidence that several adult male reproductive problems arise in utero and are signs of testicular dysgenesis syndrome (TDS). Although TDS might result from genetic mutations, recent evidence suggests that it most often is related to environmental exposures of the fetal testis. However, environmental factors can also affect the adult endocrine system. Based on our review of genetic and environmental factors, we conclude that environmental exposures arising from modern lifestyle, rather than genetics, are the most important factors in the observed trends. These environmental factors might act either directly or via epigenetic mechanisms. In the latter case, the effects of exposures might have an impact for several generations post-exposure. In conclusion, there is an urgent need to prioritize research in reproductive physiology and pathophysiology, particularly in highly industrialized countries facing decreasing populations. We highlight a number of topics that need attention by researchers in human physiology, pathophysiology, environmental health sciences, and demography.

Low serum anti-Müllerian hormone is associated with semen quality in infertile men and not influenced by vitamin D supplementation.

BACKGROUND: Anti-Müllerian hormone (AMH) is released by testicular Sertoli cells and of great importance during fetal male sexual development, but less is known about the role of circulating AMH during adulthood. In vitro studies have shown that vitamin D may induce AMH transcription, but a controlled trial investigating the possible effect of vitamin D on serum AMH has not been conducted in men. METHODS: A single-center, double-blinded, randomized placebo-controlled clinical trial (NCT01304927) conducted in Copenhagen, Denmark. A total of 307 infertile men were included and randomly assigned (1:1) to a single dose of 300,000 IU cholecalciferol followed by 1400 IU cholecalciferol + 500 mg of calcium daily (n = 151) or placebo (n = 156) for 150 days. Difference in serum AMH was a predefined secondary endpoint. Explorative outcomes were associations between serum AMH and gonadal function in infertile men. The primary endpoint was difference in semen quality and has previously been published. RESULTS: Infertile men in the lowest AMH tertile had significantly lower sperm concentration (∆T3-1 16 mill/mL (228%); P < 0.001), sperm count (∆T3-1 55 million (262%); P < 0.001), motile sperm count (∆T3-1 28 million (255%); P < 0.001), progressive motile sperm count (∆T3-1 18 million (300%); P < 0.001), testis size (∆T3-1 2.7 mL (16%); P < 0.001), serum inhibin B (∆T3-1 72 pg/mL (59%); P < 0.001), inhibin B/FSH ratio (∆T3-1 48 (145%); P < 0.001), and higher FSH (∆T3-1 2.6 (38%); P < 0.001) than the tertile of infertile men with highest serum AMH. Vitamin D supplementation had no effect on serum AMH compared with placebo treatment. CONCLUSIONS: In infertile men, low serum AMH is associated with severely impaired gonadal function illustrated by poor semen quality and lower testosterone/LH ratio. Serum AMH in infertile men was not influenced by vitamin D supplementation.

Identification of a window of androgen sensitivity for somatic cell function in human fetal testis cultured ex vivo.

BACKGROUND: Reduced androgen action during early fetal development has been suggested as the origin of reproductive disorders comprised within the testicular dysgenesis syndrome (TDS). This hypothesis has been supported by studies in rats demonstrating that normal male development and adult reproductive function depend on sufficient androgen exposure during a sensitive fetal period, called the masculinization programming window (MPW). The main aim of this study was therefore to examine the effects of manipulating androgen production during different timepoints during early human fetal testis development to identify the existence and timing of a possible window of androgen sensitivity resembling the MPW in rats. METHODS: The effects of experimentally reduced androgen exposure during different periods of human fetal testis development and function were examined using an established and validated human ex vivo tissue culture model. The androgen production was reduced by treatment with ketoconazole and validated by treatment with flutamide which blocks the androgen receptor. Testicular hormone production ex vivo was measured by liquid chromatography-tandem mass spectrometry or ELISA assays, and selected protein markers were assessed by immunohistochemistry. RESULTS: Ketoconazole reduced androgen production in testes from gestational weeks (GW) 7-21, which were subsequently divided into four age groups: GW 7-10, 10-12, 12-16 and 16-21. Additionally, reduced secretion of testicular hormones INSL3, AMH and Inhibin B was observed, but only in the age groups GW 7-10 and 10-12, while a decrease in the total density of germ cells and OCT4+ gonocytes was found in the GW 7-10 age group. Flutamide treatment in specimens aged GW 7-12 did not alter androgen production, but the secretion of INSL3, AMH and Inhibin B was reduced, and a reduced number of pre-spermatogonia was observed. CONCLUSIONS: This study showed that reduced androgen action during early development affects the function and density of several cell types in the human fetal testis, with similar effects observed after ketoconazole and flutamide treatment. The effects were only observed within the GW 7-14 period-thereby indicating the presence of a window of androgen sensitivity in the human fetal testis.

Assessment of biomarkers in pediatric atopic dermatitis by tape strips and skin biopsies.

BACKGROUND: The cytokine profile of atopic dermatitis (AD) depends on age, ethnicity, and disease severity. This study examined biomarkers in children with AD collected by tape strips and skin biopsies, and examined whether the levels differed with filaggrin genotype, disease severity, and food allergy. METHODS: Twenty-five children aged 2-14 years with AD were clinically examined. Skin biopsies were collected from lesional skin and tape strips were collected from lesional and non-lesional skin. We analyzed natural moisturizing factor (NMF) and 17 immune markers represented by mRNA levels in skin biopsies and protein levels in tape strips. Common filaggrin gene mutations were examined in all children. RESULTS: The cytokine profile in lesional skin was dominated by a T helper (Th) 2 response in skin biopsies, and by a general increase in innate inflammation markers (interleukin (IL)-1α, IL-1ß, IL-8, IL-18) along with TARC and CTACK in tape strips. The levels of TARC, CTACK, IL-8, IL-18 showed significant correlation with AD severity in both lesional and non-lesional tape stripped skin, while no significant correlations were observed in skin biopsy data. In tape strips from lesional and non-lesional skin, the levels of NMF and selected cytokines differed significantly between children with and without FLG mutations and food allergy. CONCLUSION: Sampling of the stratum corneum with non-invasive tape strips can be used to identify biomarkers that are associated with disease severity, food allergy and FLG mutations. Skin biopsies showed robust Th2 signature but was inferior for association analysis regarding severity.

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.

Cohort profile: The COPENHAGEN Minipuberty Study-A longitudinal prospective cohort of healthy full-term infants and their parents.

BACKGROUND: The hypothalamic-pituitary-gonadal (HPG) axis governs sexual maturation and reproductive function in humans. In early postnatal life, it is transiently active during which circulating sex steroids reach adult levels. While this so-called minipuberty represents a universal phenomenon in infants of both sexes, its role for early maturation and growth remains incompletely understood. OBJECTIVES: To provide normative data on auxology as well as serum and urinary hormone levels in healthy, full-term infants throughout the first year of life and to investigate associations of postnatal HPG axis dynamics as well as hormonal, genetic and environmental exposures with early genital development and growth. POPULATION: Healthy, Danish, full-term, singleton newborns including their parents. DESIGN: Single-centre, prospective, observational longitudinal pregnancy and birth cohort. METHODS: Newborns were followed with six repeated clinical examinations during a one-year follow-up period. An umbilical cord blood sample was drawn at birth. At each visit, infants underwent a clinical examination focusing on auxology and genital development. Further, blood (serum, plasma, DNA) and urine samples were collected at each visit. Mothers and fathers underwent a clinical examination and provided blood samples prior to and after birth. A subset of parents provided urine samples and breast milk samples. Pregnancy and obstetrical outcomes, and detailed parental questionnaires were compiled. PRELIMINARY RESULTS: Between August 2016 and August 2018, 2481 women with singleton pregnancies were invited to participate of which 298, including their partners, were enrolled (12.0%). A total of 268 healthy, full-term newborns born appropriate for gestational age (AGA) were included at birth, 233 newborns participated in the postnatal follow-up period and 186 completed the one-year follow-up period (9.4% and 7.5%, respectively). CONCLUSION: The COPENHAGEN Minipuberty Study provides detailed, longitudinal data on early genital development and growth including hormonal and genetic profiles and environmental exposure in healthy infants including additional data in their parents.

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.

Use of e-cigarettes associated with lower sperm counts in a cross-sectional study of young men from the general population.

STUDY QUESTION: Are use of e-cigarettes and snuff associated with testicular function as previously shown for conventional cigarettes and marijuana? SUMMARY ANSWER: Use of e-cigarettes is associated with reduced semen quality but not with higher serum testosterone level as observed for conventional cigarette use. Snuff use was not associated with markers of testicular function. WHAT IS KNOWN ALREADY: Cigarette smoking has previously been associated with higher testosterone levels and impaired semen quality, whereas it is unresolved whether use of e-cigarettes or snuff influence the testicular function. STUDY DESIGN, SIZE, DURATION: This cross-sectional population-based study included 2008 men with information on cigarette and marijuana use (enrolled between 2012 and 2018), among whom 1221 men also had information on e-cigarette and snuff use (enrolled between 2015 and 2018). PARTICIPANTS/MATERIALS, SETTING, METHODS: Men (median age 19.0 years) from the general population provided a semen and blood sample and filled out a questionnaire on lifestyle including information on smoking behaviour. Associations between different types of smoking (e-cigarettes, snuff, marijuana and cigarettes) and reproductive hormones (total and free testosterone, sex hormone-binding globulin, LH, oestradiol and ratios of inhibin B/FSH, testosterone/LH and free testosterone/LH) and semen parameters (total sperm count and sperm concentration) were examined using multiple linear regression analyses adjusted for relevant confounders. MAIN RESULTS AND THE ROLE OF CHANCE: Approximately half of the men (52%) were cigarette smokers, 13% used e-cigarettes, 25% used snuff and 33% used marijuana. Users of e-cigarettes and marijuana were often also cigarette smokers. Compared to non-users, daily e-cigarette users had significantly lower total sperm count (147 million vs 91 million) as did daily cigarette smokers (139 million vs 103 million), in adjusted analyses. Furthermore, significantly higher total and free testosterone levels were seen in cigarette smoking men (6.2% and 4.1% higher total testosterone and 6.2% and 6.2% higher free testosterone in daily smokers and occasional smokers, respectively, compared to non-smoking men), but not among e-cigarette users. Daily users of marijuana had 8.3% higher total testosterone levels compared to non-users. No associations were observed for snuff in relation to markers of testicular function. LIMITATIONS, REASONS FOR CAUTION: We cannot exclude that our results can be influenced by residual confounding by behavioural factors not adjusted for. The number of daily e-cigarette users was limited and findings should be replicated in other studies. WIDER IMPLICATIONS OF THE FINDINGS: This is the first human study to indicate that not only cigarette smoking but also use of e-cigarettes is associated with lower sperm counts. This could be important knowledge for men trying to achieve a pregnancy, as e-cigarettes are often considered to be less harmful than conventional cigarette smoking. STUDY FUNDING/COMPETING INTEREST(S): Funding was received from the Danish Ministry of Health (1-1010-308/59), the Independent Research Fund Denmark (8020-00218B), ReproUnion (20200407) and the Research Fund of the Capital Region of Denmark (A6176). The authors have nothing to disclose. TRIAL REGISTRATION NUMBER: NA.

The LH/FSH ratio is not a sex-dimorphic marker after infancy: data from 6417 healthy individuals and 125 patients with Differences of Sex Development.

STUDY QUESTION: What is the course of the LH/FSH ratio from infancy into adulthood in healthy individuals and in patients with Differences of Sex Development (DSD)? SUMMARY ANSWER: The LH/FSH ratio had a marked overlap between the sexes after infancy and onwards throughout adulthood in healthy individuals and it was not a marker of hypogonadism in DSD patients. WHAT IS KNOWN ALREADY: The LH/FSH ratio is a distinct marker of sex during minipuberty. No study has evaluated the LH/FSH ratio from infancy into adulthood. STUDY DESIGN, SIZE, DURATION: This was a combined study of prospective longitudinal and cross-sectional cohorts of healthy individuals totaling 6417 males and females aged 0-80 years. Retrospective data from a single, tertiary center on 125 patients with DSD was also included. PARTICIPANTS/MATERIALS, SETTING, METHODS: Based on the healthy males (n = 3144) and females (n = 3273) aged 0-80 years, reference ranges for LH, FSH and the LH/FSH ratio were established from infancy (after minipuberty) and onwards. LH, FSH, and the LH/FSH ratio in 125 patients with DSD not undergoing treatment were compared to the reference ranges. Included DSD diagnoses were: Klinefelter syndrome including mosaic variants (males: n = 14), Turner syndrome including mosaic variants without Y-chromosome material (females: n = 48), 45,X/46,XY mosaicism (males: n = 24 and females: n = 6), partial androgen insensitivity syndrome (males: n = 11), complete androgen insensitivity syndrome (females: n = 13) and anorchia (males: n = 9). MAIN RESULTS AND THE ROLE OF CHANCE: An overlap was observed in the LH/FSH ratio reference curves between males and females. However, when comparing the sexes at specific time points, the LH/FSH ratio was significantly higher in healthy males during childhood and adulthood and significantly higher in healthy females during puberty. When compared with healthy participants, male patients with anorchia and 45,X/46,XY mosaicism had significantly lower ratios, while patients with androgen insensitivity, regardless of sex, had significantly higher ratios. LIMITATIONS, REASONS FOR CAUTION: The limitations of this study include that; (i) all healthy individuals were Caucasian, so conclusions may not apply to non-Caucasians; (ii) the calculated LH/FSH ratios were restricted to the specific analytical method used and may not be applicable to other laboratories; (iii) the samples from healthy individuals were stored for varying amounts of time up to 20 years which may affect the durability; and (iv) DSD diagnoses are heterogeneous thus making sturdy conclusions across diagnoses impossible. WIDER IMPLICATIONS OF THE FINDINGS: In this study of combined cohorts of healthy participants, the largest normative ranges of LH, FSH, and the LH/FSH ratio to date were created. These reference ranges provide the opportunity for clinical as well as research use for all three markers. However, the previously rather undescribed LH/FSH ratio was not a distinct marker of sex after infancy nor a new marker of hypogonadism. Although there were significant differences between subgroups of DSD patients compared to healthy controls, the clinical significance of the LH/FSH ratio after infancy lacked. However, it can be speculated whether there are other areas of clinical application not investigated in this article, for example as a marker of fertility in select patient groups. As gonadotropin assays are readily available and gonadotropin measurements are part of regular workups, the LH/FSH ratio can easily be explored in further research without additional costs. STUDY FUNDING/COMPETING INTEREST(S): M.L.L. was funded by the Absalon Foundation. Cohort 1 was funded by the European Commission, through the Biomed 2 Program (BMH4-CT96-0314), Environmental Reproductive Health (QLK4-CT1999-01422) and EXPORED (QLK4-2001-00269), by the Danish Council for Independent Research (9700833 and 9700909), and by the Svend Andersens Foundation. Cohort 2 was funded by the Danish Environmental Research Program (96.01.015.16.05). Cohort 3 was funded by Kirsten and Freddy Johansens Foundation. TRIAL REGISTRATION NUMBER: NA. DATE OF FIRST PATIENT'S ENROLMENT: June 1990 (the launch of the department from which this project stems).

Predicting Transdermal Uptake of Phthalates and a Paraben from Cosmetic Cream Using the Measured Fugacity.

Transdermal uptake models compliment in vitro and in vivo experiments in assessing risk of environmental exposures to semivolatile organic compounds (SVOCs). A key parameter for mechanistic models is the chemical driving force for mass transfer from environmental media to human skin. In this research, we measure this driving force in the form of fugacity for chemicals in cosmetic cream and use it to model uptake from cosmetics as a surrogate for condensed environmental media. A simple cosmetic cream, containing no target analytes, was mixed with diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), and butyl paraben (BP) and diluted to make creams with concentrations ranging from 0.025% to 6%. The fugacity, relative to the pure compound, was measured using solid-phase micro extraction (SPME). We found that the relationship between the concentration and fugacity is highly nonlinear. The relative fugacity of the chemicals for a 2% w/w formulation was used in a diffusion-based model to predict transdermal uptake of each chemical and was compared with excretion data from a prior human subject study with the same formulation. Dynamic simulations of excretion are generally consistent with the results of the human subject experiment but sensitive to the input parameters, especially the time between cream application and showering.

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.

Use of stored serum in the study of time trends and geographical differences in exposure of pregnant women to phthalates.

BACKGROUND: Exposure to some phthalate diesters has been associated with adverse reproductive health outcomes in both rodents and humans indicative of anti-androgenic effects. Exposure during sensitive periods of development, such as prenatally, is of particular concern. OBJECTIVES: We wished to investigate whether phthalate metabolites measured in maternal serum samples from historical birth cohorts can be used to assess prenatal exposure. Further, we aimed to study temporal and geographical trends in phthalate exposure across three different birth cohorts. METHODS: We compared phthalate metabolite levels in maternal serum samples from an Australian (1989-91) and a Danish (1997-2001) birth cohort with levels in serum and urine samples from a recent Danish birth cohort (2012-14). Samples were analysed for 32 phthalate metabolites from 15 phthalate diesters by isotope-diluted liquid chromatography-tandem mass spectrometry (LC-MS/MS). Correlations between metabolites were tested by Spearman rank correlation test, and differences between the cohorts were tested by Mann-Whitney U test. RESULTS: Overall, we observed large variations in serum phthalate metabolite levels between individuals. Secondary metabolites of di-(2-ethyl-hexyl) phthalate (DEHP) and di-iso-nonyl phthalate (DiNP) in serum were weakly to moderately and positively correlated to the levels measured in urine, and secondary metabolites of DEHP were also moderately to strongly and significantly correlated in serum. Correlations with mono-(2-ethyl-hexyl) phthalate (MEHP) and mono-iso-nonyl phthalate (MiNP), the two primary metabolites of DEHP and DiNP, were inconsistent, and we found indications of sample contamination. We observed some significant differences in phthalate metabolite levels between the three cohorts with generally higher levels in the older birth cohorts. CONCLUSION: Based on comparison across two older birth cohorts and a recent cohort, our results support the concept that historical biobanked serum samples may be used for assessment of prenatal exposure to phthalates when using serum levels of the monoesters of the low-molecular weight (LMW) phthalates and the secondary metabolites of the high-molecular weight (HMW) phthalates. Serum phthalate measurements are, however, not suitable for human biomonitoring and should only be used to exploit historical samples from cohorts, where urine samples were not collected. Our findings suggest that phthalate exposure may have decreased over time from the early 1990s to the 2010s.

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 ΣDiNPm and di-2-ethylhexyl phthalate metabolite (ΣDEHPm) 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 ΣDiNPm 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.

Impacts of food contact chemicals on human health: a consensus statement.

Food packaging is of high societal value because it conserves and protects food, makes food transportable and conveys information to consumers. It is also relevant for marketing, which is of economic significance. Other types of food contact articles, such as storage containers, processing equipment and filling lines, are also important for food production and food supply. Food contact articles are made up of one or multiple different food contact materials and consist of food contact chemicals. However, food contact chemicals transfer from all types of food contact materials and articles into food and, consequently, are taken up by humans. Here we highlight topics of concern based on scientific findings showing that food contact materials and articles are a relevant exposure pathway for known hazardous substances as well as for a plethora of toxicologically uncharacterized chemicals, both intentionally and non-intentionally added. We describe areas of certainty, like the fact that chemicals migrate from food contact articles into food, and uncertainty, for example unidentified chemicals migrating into food. Current safety assessment of food contact chemicals is ineffective at protecting human health. In addition, society is striving for waste reduction with a focus on food packaging. As a result, solutions are being developed toward reuse, recycling or alternative (non-plastic) materials. However, the critical aspect of chemical safety is often ignored. Developing solutions for improving the safety of food contact chemicals and for tackling the circular economy must include current scientific knowledge. This cannot be done in isolation but must include all relevant experts and stakeholders. Therefore, we provide an overview of areas of concern and related activities that will improve the safety of food contact articles and support a circular economy. Our aim is to initiate a broader discussion involving scientists with relevant expertise but not currently working on food contact materials, and decision makers and influencers addressing single-use food packaging due to environmental concerns. Ultimately, we aim to support science-based decision making in the interest of improving public health. Notably, reducing exposure to hazardous food contact chemicals contributes to the prevention of associated chronic diseases in the human population.

Prognostic imaging biomarkers for diabetic kidney disease (iBEAt): study protocol.

BACKGROUND: Diabetic kidney disease (DKD) remains one of the leading causes of premature death in diabetes. DKD is classified on albuminuria and reduced kidney function (estimated glomerular filtration rate (eGFR)) but these have modest value for predicting future renal status. There is an unmet need for biomarkers that can be used in clinical settings which also improve prediction of renal decline on top of routinely available data, particularly in the early stages. The iBEAt study of the BEAt-DKD project aims to determine whether renal imaging biomarkers (magnetic resonance imaging (MRI) and ultrasound (US)) provide insight into the pathogenesis and heterogeneity of DKD (primary aim) and whether they have potential as prognostic biomarkers in DKD (secondary aim). METHODS: iBEAt is a prospective multi-centre observational cohort study recruiting 500 patients with type 2 diabetes (T2D) and eGFR ≥30 ml/min/1.73m2. At baseline, blood and urine will be collected, clinical examinations will be performed, and medical history will be obtained. These assessments will be repeated annually for 3 years. At baseline each participant will also undergo quantitative renal MRI and US with central processing of MRI images. Biological samples will be stored in a central laboratory for biomarker and validation studies, and data in a central data depository. Data analysis will explore the potential associations between imaging biomarkers and renal function, and whether the imaging biomarkers improve the prediction of DKD progression. Ancillary substudies will: (1) validate imaging biomarkers against renal histopathology; (2) validate MRI based renal blood flow measurements against H2O15 positron-emission tomography (PET); (3) validate methods for (semi-)automated processing of renal MRI; (4) examine longitudinal changes in imaging biomarkers; (5) examine whether glycocalyx and microvascular measures are associated with imaging biomarkers and eGFR decline; (6) explore whether the findings in T2D can be extrapolated to type 1 diabetes. DISCUSSION: iBEAt is the largest DKD imaging study to date and will provide valuable insights into the progression and heterogeneity of DKD. The results may contribute to a more personalised approach to DKD management in patients with T2D. TRIAL REGISTRATION: Clinicaltrials.gov ( NCT03716401 ).

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.

A European inter-laboratory trial to evaluate the performance of three serological methods for diagnosis of Mycoplasma bovis infection in cattle using latent class analysis.

BACKGROUND: Mycoplasma bovis (M. bovis) is an emerging bovine pathogen, leading to significant economic losses in the livestock industry worldwide. Infection can result in a variety of clinical signs, such as arthritis, pneumonia, mastitis and keratoconjunctivitis, none of which are M. bovis-specific. Laboratory diagnosis is therefore important. Serological tests to detect M. bovis antibodies is considered an effective indicator of infection in a herd and often used as a herd test. Combined with clinical judgement, it can also be used to implement control strategies and/or to estimate the disease prevalence within a country. However, due to lack of harmonisation of approaches to testing, and serological tests used by different laboratories, comparisons of prevalence data between countries is often difficult. A network of researchers from six European countries designed and participated in an inter-laboratory trial, with the aim of evaluating the sensitivity (Se) and specificity (Sp) of two commercially available ELISA tests (ID Screen® ELISA (IDvet) and BIO K302 ELISA (BIO-X Diagnostics)) for diagnosis of M. bovis infection. Each laboratory received a blinded panel of bovine sera and tested independently, according to manufacturer's instructions. Western blot analyses (WB) performed by one of the participating laboratories was used as a third diagnostic test in the statistical evaluation of Se and Sp values using latent class analysis. RESULTS: The Se of WB, the ID Screen® ELISA and the BIO K302 ELISA were determined to be 91.8, 93.5 and 49.1% respectively, and corresponding Sp of the three tests were 99.6, 98.6 and 89.6%, respectively. CONCLUSIONS: The present study is, to our knowledge, the first to present an inter-laboratory comparison of the BIO K302 ELISA and the ID Screen® ELISA. Based on our results, the ID Screen® ELISA showed high consistency with WB and performed with higher precision and accuracy than the BIO K302 ELISA.

A European interlaboratory trial to evaluate the performance of different PCR methods for Mycoplasma bovis diagnosis.

BACKGROUND: Several species-specific PCR assays, based on a variety of target genes are currently used in the diagnosis of Mycoplasma bovis infections in cattle herds with respiratory diseases and/or mastitis. With this diversity of methods, and the development of new methods and formats, regular performance comparisons are required to ascertain diagnostic quality. The present study compares PCR methods that are currently used in six national veterinary institutes across Europe. Three different sample panels were compiled and analysed to assess the analytical specificity, analytical sensitivity and comparability of the different PCR methods. The results were also compared, when appropriate, to those obtained through isolation by culture. The sensitivity and comparability panels were composed of samples from bronchoalveolar fluids of veal calves, artificially contaminated or naturally infected, and hence the comparison of the different methods included the whole workflow from DNA extraction to PCR analysis. RESULTS: The participating laboratories used i) five different DNA extraction methods, ii) seven different real-time and/or end-point PCRs targeting four different genes and iii) six different real-time PCR platforms. Only one commercial kit was assessed; all other PCR assays were in-house tests adapted from published methods. The analytical specificity of the different PCR methods was comparable except for one laboratory where Mycoplasma agalactiae was tested positive. Frequently, weak-positive results with Ct values between 37 and 40 were obtained for non-target Mycoplasma strains. The limit of detection (LOD) varied from 10 to 103 CFU/ml to 103 and 106 CFU/ml for the real-time and end-point assays, respectively. Cultures were also shown to detect concentrations down to 102 CFU/ml. Although Ct values showed considerable variation with naturally infected samples, both between laboratories and tests, the final result interpretation of the samples (positive versus negative) was essentially the same between the different laboratories. CONCLUSION: With a few exceptions, all methods used routinely in the participating laboratories showed comparable performance, which assures the quality of diagnosis, despite the multiplicity of the methods.

Low-saturated-fat and low-cholesterol diet does not alter pubertal development and hormonal status in adolescents.

AIM: The aim was to assess the influence of dietary counselling on the pubertal development and hormonal status in healthy adolescents. METHODS: We used a subcohort of 193 healthy boys (52%) and girls (48%) from the Special Turku Coronary Risk Factor Intervention Project. Participants were recruited by nurses at the well-baby clinics in Turku Finland in 1990-1992 and randomised into intervention and control groups. Intervention children received low-saturated fat and low-cholesterol dietary counselling initiated at seven months of age. Participants were examined once a year with Tanner staging, anthropometric measurements and serial reproductive hormones from 10 to 19 years of age. In girls, postmenarcheal hormones were not analysed. RESULTS: Pubertal hormones in boys or girls did not differ between the intervention and control groups. However, we observed slight differences in pubertal progression by Tanner staging and in anthropometric parameters. The intervention boys progressed faster to G4 (p = 0.008), G5 (p = 0.008) and P5 (p = 0.03). The intervention boys were taller than control boys (p = 0.04), while weight and body mass index did not differ. CONCLUSION: Dietary intervention did not affect pubertal hormonal status. This finding supports the safety of implemented counselling in respect to puberty.

Anogenital distance as a phenotypic signature through infancy.

BackgroundAnogenital distance (AGD) has been suggested to represent a phenotypic signature reflecting in utero androgen action. However, it is not known whether an individual's AGD at birth correlates to the AGD later in life. We investigate correlations of AGD between 3 and 18 months of age and assess reproducibility of measurements.MethodsWe measured AGD from anus to scrotum (AGDas) and to penis (AGDap) in 407 boys, and to posterior fourchette (AGDaf) and clitoris (AGDac) in 282 girls. Each measure was repeated three times at 3 and 18 months of age, and some children were, furthermore, examined by two different examiners. We assessed age-related changes and reproducibility of measurements.ResultsAGD increased between the two examinations and correlated within the child. A large proportion of the observed variation in AGD was due to true differences between the children (AGDas: 62%, AGDap: 40%, AGDaf: 30%, AGDac: 21%), and measurement error due to between- and within-examiner variation was low.ConclusionsOur study showed that measures of AGD within a child correlated during infancy, especially in boys and particularly for AGD measured as the distance between anus and scrotum. A planned cohort follow-up through childhood and puberty will reveal whether AGD represents a phenotypic signature throughout life.