The epidemiology of cryptorchidism and potential risk factors, including endocrine disrupting chemicals.

Congenital cryptorchidism, also known as undescended testis, is the condition where one or both testes are not in place in the scrotum at birth and is one of the most common birth defects in boys. Temporal trends and geographic variation in the prevalence of cryptorchidism from 1% to 9% have been reported in prospective cohort studies. The testes develop in the abdominal cavity and descend to the scrotum in two phases, which should be completed by gestational week 35. Thus, the risk of cryptorchidism is higher in preterm boys. In many cases a spontaneous descent occurs during the first months of life during the surge of gonadotropins and testosterone. If not, the testis is usually brought down to the scrotum, typically by surgery, to increase future fertility chances and facilitate cancer surveillance. The increasing frequency of impaired semen quality and testicular cancer, with which cryptorchidism is associated, represents a concern for male reproductive health in general and a need to understand its risk factors. The risk of cryptorchidism is closely related to gestational factors (preterm birth, low birth weight and intrauterine growth restriction), and especially maternal smoking seems to be a risk factor. Evidence is accumulating that the increasing prevalence of cryptorchidism is also related to prenatal exposure to environmental chemicals, including endocrine disrupting compounds. This association has been corroborated in rodents and supported by ecological studies. Conducting human studies to assess the effect of endocrine disrupting chemicals and their interactions is, however, challenged by the widespread concomitant exposure of all humans to a wide range of chemicals, the combined effect of which and their interactions are highly complex.

Antibiotic Use in Dental Care of Dogs, Cats, and Rabbits in Sweden.

Antimicrobial resistance is one of the largest threats to global health. In society as well as in healthcare facilities, antimicrobial resistance is rapidly increasing with the main reason being overuse and misuse of antibiotics combined with inadequate infection prevention. For humans, dental care accounts for about 10% of all antibiotic prescriptions, making it an important target for antibiotic stewardship interventions. Corresponding figures for veterinary care are currently lacking but dental disease is frequently diagnosed in small animals. An important first step in the work towards prudent use of antibiotics is to understand antibiotic prescription habits and through that estimate the adherence to veterinary antibiotic guidelines as well as the need for education, training, and improved policies. The aim of this article is to present the results of a multicentre point prevalence survey sent to Swedish IVC Evidensia practices during autumn 2021 to recognize the use of antibiotics associated with dental treatments in dogs, cats, and rabbits. During the study period, 4.4% of the dental patients in Swedish IVC Evidensia small animal veterinary practices received antibiotics. The most used antibiotics prescribed were ampicillin, amoxicillin, and clindamycin indicating an overall high level of compliance to veterinary dental guidelines. This article demonstrates that Swedish veterinarians use antibiotics prudently in small animal dentistry and the results may be used as a future global benchmark.

Ovarian follicular fluid levels of phthalates and benzophenones in relation to fertility outcomes.

BACKGROUND: Many endocrine disrupting chemicals (EDCs), for instance phthalates and benzophenones, are associated with adverse fertility outcomes and semen quality parameters. OBJECTIVE: To evaluate if concentrations of selected phthalate metabolites and benzophenones measured in follicular fluid are associated with fertility outcomes (i.e., reproductive hormones, antral follicle count, detected heartbeat at gestational week 7, and live birth) and, in a supplementary study, if measured concentrations of chemicals in follicular fluid can exert biological effects on human spermatozoa. METHODS: Overall, 111 couples from a fertility clinic in Denmark contributed with 155 follicular fluid samples. Concentrations of 43 metabolites from 19 phthalates and phthalate substitutes and six benzophenones were measured in follicular fluid using liquid chromatography-tandem mass spectrometry. Multiple linear and logistic regression with an applied generalized estimating equation model allowing more than one measurement per woman assessed the association between follicular EDC levels and fertility outcomes. The assessment of biological effects of individual and mixtures of EDCs on human spermatozoa was conducted through a human sperm cell based Ca2+-fluorimetric assay. RESULTS: Benzophenone-3 (BP-3) and seven metabolites of five phthalates were detectable in follicular fluid. Women with metabolites of dibutyl phthalate isomers in the highest tertiles had lower antral follicle count (MiBP: ß = -5.35 [95 % CI: -9.06; -2.00], MnBP: ß = -5.25 [95 % CI: -9.00; -2.00]) and lower odds for detecting a heartbeat at gestational week 7 (MiBP: OR = 0.35 [95 % CI: 0.14; 0.91], MnBP: OR = 0.39 [95 % CI: 0.13; 1.15]). Mixtures of the measured concentrations of BP-3 and the seven phthalate metabolites induced a small significant increase in the intracellular calcium ion concentration in human spermatozoa from healthy donors (n = 3). DISCUSSION: Phthalate metabolites and BP-3 were detectable in follicular fluid and high concentrations of some phthalate metabolites were linked with lower chance of successful fertility treatment outcomes. Chemical mixture concentrations in follicular fluid induced a calcium response in human spermatozoa highlighting possible biological effects at physiologically relevant concentrations.

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.

Time Patterns in Internal Human Exposure Data to Bisphenols, Phthalates, DINCH, Organophosphate Flame Retardants, Cadmium and Polyaromatic Hydrocarbons in Europe.

Human biomonitoring (HBM) data in Europe are often fragmented and collected in different EU countries and sampling periods. Exposure levels for children and adult women in Europe were evaluated over time. For the period 2000-2010, literature and aggregated data were collected in a harmonized way across studies. Between 2011-2012, biobanked samples from the DEMOCOPHES project were used. For 2014-2021, HBM data were generated within the HBM4EU Aligned Studies. Time patterns on internal exposure were evaluated visually and statistically using the 50th and 90th percentiles (P50/P90) for phthalates/DINCH and organophosphorus flame retardants (OPFRs) in children (5-12 years), and cadmium, bisphenols and polycyclic aromatic hydrocarbons (PAHs) in women (24-52 years). Restricted phthalate metabolites show decreasing patterns for children. Phthalate substitute, DINCH, shows a non-significant increasing pattern. For OPFRs, no trends were statistically significant. For women, BPA shows a clear decreasing pattern, while substitutes BPF and BPS show an increasing pattern coinciding with the BPA restrictions introduced. No clear patterns are observed for PAHs or cadmium. Although the causal relations were not studied as such, exposure levels to chemicals restricted at EU level visually decreased, while the levels for some of their substitutes increased. The results support policy efficacy monitoring and the policy-supportive role played by HBM.

Evaporation of serum after long-term biobank storage: A chemical analysis of maternal serum from a large Danish pregnancy screening registry.

BACKGROUND: Relying on freezer stored biospecimens is preferred in epidemiolocal studies exploring environmental pregnancy exposures and later offspring health. Storage duration may increase the pre-analytical variability, potentially adding measurement uncertainty. We investigated evaporation of maternal serum after long-term biobank storage using ions (sodium, Na+; chloride, Cl-) recognized for stability and relatively narrow normal biological reference ranges in human serum. METHODS: A chemical analysis study of 275 biobanked second trimester maternal serum from a large Danish pregnancy screening registry. Serum samples were collected between 1985-1995 and stored at -20°C. Ion concentrations were quantified with indirect potentiometry using a Roche Cobas 6000 analyzer and compared according to storage time and normal biological ranges in second trimester. Ion concentrations were also compared with normal biological variation assessed by baseline Na+ and Cl- serum concentrations from a separate cohort of 24,199 non-pregnant women measured before freezing with the same instrument. RESULTS: The overall mean ion concentrations in biobanked serum were 147.5 mmol/L for Na+ and 109.7 for Cl-. No marked linear storage effects were observed according to storage time. Ion concentrations were consistently high across sampling years, especially for specific sampling years, and a relatively large proportion were outside respective normal ranges in second trimester: 38.9% for Na+ and 43.6% for Cl-. Some variation in concentrations was also evident in baseline serum used as quality controls. CONCLUSIONS: Elevated ion concentrations suggest evaporation, but independent of storage duration in the present study (27-37 years). Any evaporation may have occurred prior to freezer storage or during the first 27 years. Other pre-analytical factors such as low serum volume have likely influenced the concentrations, particularly given the high within year variability. Overall, we consider the biobanked serum samples internally comparable to enable their use in epidemiological studies.

A vision for safer food contact materials: Public health concerns as drivers for improved testing.

Food contact materials (FCMs) and food contact articles are ubiquitous in today's globalized food system. Chemicals migrate from FCMs into foodstuffs, so called food contact chemicals (FCCs), but current regulatory requirements do not sufficiently protect public health from hazardous FCCs because only individual substances used to make FCMs are tested and mostly only for genotoxicity while endocrine disruption and other hazard properties are disregarded. Indeed, FCMs are a known source of a wide range of hazardous chemicals, and they likely contribute to highly prevalent non-communicable diseases. FCMs can also include non-intentionally added substances (NIAS), which often are unknown and therefore not subject to risk assessment. To address these important shortcomings, we outline how the safety of FCMs may be improved by (1) testing the overall migrate, including (unknown) NIAS, of finished food contact articles, and (2) expanding toxicological testing beyond genotoxicity to multiple endpoints associated with non-communicable diseases relevant to human health. To identify mechanistic endpoints for testing, we group chronic health outcomes associated with chemical exposure into Six Clusters of Disease (SCOD) and we propose that finished food contact articles should be tested for their impacts on these SCOD. Research should focus on developing robust, relevant, and sensitive in-vitro assays based on mechanistic information linked to the SCOD, e.g., through Adverse Outcome Pathways (AOPs) or Key Characteristics of Toxicants. Implementing this vision will improve prevention of chronic diseases that are associated with hazardous chemical exposures, including from FCMs.

Urinary concentration of phthalates and bisphenol A during minipuberty is associated with reproductive hormone concentrations in infant boys.

BACKGROUND: The transient postnatal activation of the hypothalamic-pituitary-gonadal hormone axis is termed minipuberty and considered an important developmental period, which is highly sensitive to endocrine disruption. Here, we explore exposure-outcome associations during minipuberty between concentrations of potentially endocrine disrupting chemicals (EDCs) in urine of infant boys and their serum reproductive hormone concentrations. METHODS: In total, 36 boys participating in the COPENHAGEN Minipuberty Study had data available for both urine biomarkers of target endocrine disrupting chemicals and reproductive hormones in serum from samples collected on the same day. Serum concentrations of reproductive hormones were measured by immunoassays or by LC-MS/MS. Urinary concentrations of metabolites of 39 non-persisting chemicals, including phthalates and phenolic compounds, were measured by LC-MS/MS. Nineteen chemicals had concentrations above the limit of detection in ≥50% of children and were included in data analysis. Associations of urinary phthalate metabolite and phenol concentrations (in tertiles) with hormone outcomes (age- and sex-specific SD-scores) were analysed by linear regression. Primarily, we focused on the EU regulated phthalates; butylbenzyl phthalate (BBzP), di-iso-butyl phthalate (DiBP), di-n-butyl phthalate (DnBP), and di-(2-ethylhexyl) phthalate (DEHP) as well as bisphenol A (BPA). Urinary metabolites of DiBP, DnBP and DEHP were summed and expressed as ∑DiBPm, ∑DnBPm and ∑DEHPm. RESULTS: Compared to boys in the lowest ∑DnBPm tertile, urinary concentration of ∑DnBPm was associated with concurrent higher luteinizing hormone (LH) and anti-Müllerian hormone (AMH) SD-scores as well as lower testosterone/LH ratio in boys in the middle ∑DnBPm tertile (estimates (CI 95%) 0.79 (0.04; 1.54), 0.91 (0.13; 1.68), and -0.88 (-1.58;-0.19), respectively). Further, higher insulin-like peptide 3 (INSL3) SD-scores and lower DHEAS SD-score in boys in the highest ∑DnBPm tertile (0.91 (0.12; 1.70) and -0.85 (-1.51;-0.18), respectively) were observed. In addition, boys in the middle and highest ∑DEHPm tertile had higher LH (1.07 (0.35; 1.79) and 0.71 (-0.01; 1.43), respectively) and in the highest ∑DEHPm tertile also higher AMH (0.85 (0.10; 1.61)) concentration SD-scores, respectively. Boys in the highest BPA tertile had significantly higher AMH and lower DHEAS concentration compared to boys in the lowest BPA tertile (1.28 (0.54; 2.02) and -0.73 (-1.45; -0.01)), respectively. DISCUSSION: Our findings indicate that exposure to chemicals with known or suspected endocrine disrupting potential, especially the EU-regulated DnBP, DEHP and BPA, may modify male reproductive hormone concentrations in infant boys suggesting that minipuberty is a critical window sensitive to endocrine disruption.

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.

Exposure to Phthalates in European Children, Adolescents and Adults since 2005: A Harmonized Approach Based on Existing HBM Data in the HBM4EU Initiative.

Phthalates are mainly used as plasticizers and are associated inter alia with adverse effects on reproductive functions. While more and more national programs in Europe have started monitoring internal exposure to phthalates and its substitute 1,2-Cyclohexanedicarboxylic acid (DINCH), the comparability of results from such existing human biomonitoring (HBM) studies across Europe is challenging. They differ widely in time periods, study samples, degree of geographical coverage, design, analytical methodology, biomarker selection, and analytical quality assurance level. The HBM4EU initiative has gathered existing HBM data of 29 studies from participating countries, covering all European regions and Israel. The data were prepared and aggregated by a harmonized procedure with the aim to describe-as comparably as possible-the EU-wide general population's internal exposure to phthalates from the years 2005 to 2019. Most data were available from Northern (up to 6 studies and up to 13 time points), Western (11; 19), and Eastern Europe (9; 12), e.g., allowing for the investigation of time patterns. While the bandwidth of exposure was generally similar, we still observed regional differences for Butyl benzyl phthalate (BBzP), Di(2-ethylhexyl) phthalate (DEHP), Di-isononyl phthalate (DiNP), and Di-isobutyl phthalate (DiBP) with pronounced decreases over time in Northern and Western Europe, and to a lesser degree in Eastern Europe. Differences between age groups were visible for Di-n-butyl phthalate (DnBP), where children (3 to 5-year olds and 6 to 11-year olds) had lower urinary concentrations than adolescents (12 to 19-year-olds), who in turn had lower urinary concentrations than adults (20 to 39-year-olds). This study is a step towards making internal exposures to phthalates comparable across countries, although standardized data were not available, targeting European data sets harmonized with respect to data formatting and calculation of aggregated data (such as developed within HBM4EU), and highlights further suggestions for improved harmonization in future studies.

Harmonized human biomonitoring in European children, teenagers and adults: EU-wide exposure data of 11 chemical substance groups from the HBM4EU Aligned Studies (2014-2021).

As one of the core elements of the European Human Biomonitoring Initiative (HBM4EU) a human biomonitoring (HBM) survey was conducted in 23 countries to generate EU-wide comparable HBM data. This survey has built on existing HBM capacity in Europe by aligning national or regional HBM studies, referred to as the HBM4EU Aligned Studies. The HBM4EU Aligned Studies included a total of 10,795 participants of three age groups: (i) 3,576 children aged 6-12 years, (ii) 3,117 teenagers aged 12-18 years and (iii) 4,102 young adults aged 20-39 years. The participants were recruited between 2014 and 2021 in 11-12 countries per age group, geographically distributed across Europe. Depending on the age group, internal exposure to phthalates and the substitute DINCH, halogenated and organophosphorus flame retardants, per- and polyfluoroalkyl substances (PFASs), cadmium, bisphenols, polycyclic aromatic hydrocarbons (PAHs), arsenic species, acrylamide, mycotoxins (deoxynivalenol (total DON)), benzophenones and selected pesticides was assessed by measuring substance specific biomarkers subjected to stringent quality control programs for chemical analysis. For substance groups analyzed in different age groups higher average exposure levels were observed in the youngest age group, i.e., phthalates/DINCH in children versus teenagers, acrylamide and pesticides in children versus adults, benzophenones in teenagers versus adults. Many biomarkers in teenagers and adults varied significantly according to educational attainment, with higher exposure levels of bisphenols, phthalates, benzophenones, PAHs and acrylamide in participants (from households) with lower educational attainment, while teenagers from households with higher educational attainment have higher exposure levels for PFASs and arsenic. In children, a social gradient was only observed for the non-specific pyrethroid metabolite 3-PBA and di-isodecyl phthalate (DiDP), with higher levels in children from households with higher educational attainment. Geographical variations were seen for all exposure biomarkers. For 15 biomarkers, the available health-based HBM guidance values were exceeded with highest exceedance rates for toxicologically relevant arsenic in teenagers (40%), 3-PBA in children (36%), and between 11 and 14% for total DON, Σ (PFOA + PFNA + PFHxS + PFOS), bisphenol S and cadmium. The infrastructure and harmonized approach succeeded in obtaining comparable European wide internal exposure data for a prioritized set of 11 chemical groups. These data serve as a reference for comparison at the global level, provide a baseline to compare the efficacy of the European Commission's chemical strategy for sustainability and will give leverage to national policy makers for the implementation of targeted measures.

Benzophenone-3: Comprehensive review of the toxicological and human evidence with meta-analysis of human biomonitoring studies.

BACKGROUND: Benzophenone-3 (BP-3) and its major metabolite benzophenone-1 (BP-1) are widely used as UV filters in sunscreens and cosmetics to prevent sunburn and skin damage, or as stabilizers to prevent photodegradation in many commercial products. As a result, their presence is ubiquitous in the environment, wildlife and humans. Based on endocrine disruption concerns, international regulatory agencies are performing a closer evaluation. OBJECTIVE AND METHODS: This work aimed to comprehensively review the available human relevant evidence for safety issues in MEDLINE/PubMed in order to create a structured database of studies, as well as to conduct an integrative analysis as part of the Human Biomonitoring for Europe (HBM4EU) Initiative. RESULTS: A total of 1,635 titles and abstracts were screened and 254 references were evaluated and tabulated in detail, and classified in different categories: i) exposure sources and predictors; ii) human biomonitoring (HBM) exposure levels to perform a meta-analysis; iii) toxicokinetic data in both experimental animals and humans; iv) in vitro and in vivo rodent toxicity studies; and v) human data on effect biomarkers and health outcomes. Our integrative analysis showed that internal peak BP-3 concentrations achieved after a single whole-body application of a commercially available sunscreen (4% w/w) may overlap with concentrations eliciting endocrine disrupting effects in vitro, and with internal concentrations causing in vivo adverse female reproductive effects in rodents that were supported by still limited human data. The adverse effects in rodents included prolonged estrous cycle, altered uterine estrogen receptor gene expression, endometrium hyperplasia and altered proliferation and histology of the mammary gland, while human data indicated menstrual cycle hormonal alterations and increased risk of uterine fibroids and endometriosis. Among the modes of action reported (estrogenic, anti-androgenic, thyroid, etc.), BP-3 and especially BP-1 showed estrogenic activity at human-relevant concentrations, in agreement with the observed alterations in female reproductive endpoints. The meta-analysis of HBM studies identified a higher concern for North Americans, showing urinary BP-3 concentrations on average 10 and 20 times higher than European and Asian populations, respectively. DISCUSSION AND CONCLUSIONS: Our work supports that these benzophenones present endocrine disrupting properties, endorsing recent European regulatory efforts to limit human exposure. The reproducible and comprehensive database generated may constitute a point of departure in future risk assessments to support regulatory initiatives. Meanwhile, individuals should not refrain from sunscreen use. Commercially available formulations using inorganic UV filters that are practically not absorbed into systemic circulation may be recommended to susceptible populations.

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.

Urinary excretion of phthalates and the substitutes DINCH and DEHTP in Danish young men and German young adults between 2000 and 2017 - A time trend analysis.

Over the last twenty-five years it has become evident that exposure to several phthalates can have adverse effects on human health, such as endocrine disruption. This led to a series of EU regulations that resulted in a decrease in the production volumes of the restricted phthalates and an increased production of substitutes. The current study describes the impact of regulations and changes in production and use of phthalates and their substitutes on internal exposure patterns in two European populations since the beginning of the 2000'ies. Using harmonised data from young adults in Denmark (Danish Young Men Study, n = 1,063, spot urine) and Germany (Environmental Specimen Bank, n = 878, 24-h urine) with repeated cross-sectional design (3-11 cycles per biomarker) we applied Locally Estimated Scatterplot Smoothing (LOESS) and Generalized Linear Models (GLMs) to estimate time trends and the role of covariates on the trend (e.g. age, BMI). Time trends of daily excretion (µg/24h) are comparable between the two samples for the regulated (DEHP, BBzP, DiNP, DnBP, DiBP, DiDP/DPHP) as well as the non-regulated substances (DMP, DEP, DINCH, DEHTP) although the rate of change differ for some of the compounds. GLM results indicate that the daily excretion of the most regulated phthalates has decreased over time (DEHP yearly about 12-16%, BBzP 5%, DnBP 0.3-17%, and DiBP 4-12%). Interestingly, also the non-regulated phthalates DMP and DEP decreased by 6-18% per year. In sharp contrast, the phthalate substitutes DINCH and DEHTP show very steep annual increases (∼10-68% and ∼100%, respectively) between 2009 and 2017. We did not find an effect of age, sex, BMI, or education on the time trend. The present study provides comparable insights into how exposure to phthalates and two of their substitutes have changed over the last two decades in Germany and Denmark.

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.

Serum LH/FSH ratios in 87 infants with differences of sex development.

The ratio between luteinizing hormone (LH) and follicle-stimulating hormone (FSH) has previously been described as an excellent marker of sex in healthy infants. However, LH/FSH remains not fully described in patients with differences of sex development (DSD). The aim was therefore to describe LH/FSH in infants with DSD. This was a retrospective study of DSD patients, all aged 0-1.2 years. In total, 87 infants with DSD and at least one serum sample per infant were included. Longitudinal samples from single patients were included whenever possible. Serum LH/FSH ratios in these patients were plotted against recently published age-related and sex-dimorphic cutoffs. Overall, LH/FSH sometimes corresponded to assigned sex without any obvious pattern in terms of diagnoses. LH/FSH corresponded to the biological sex in all patients with Turner or Klinefelter syndrome. In patients with 46,XX or 46,XY DSD (except congenital adrenal hyperplasia (CAH)), the ratios did not correspond to the assigned sex in all cases and were interchangeably within the male and female range. In patients with CAH, the ratio corresponded to biological sex (based on sex chromosomes) in some cases but also ranged across the cutoffs. In the 15 patients with 45,X/46,XY mosaicism, the LH/FSH ratios corresponded to the assigned sex in all cases (12 were raised as males, 3 as females) and at all time points in cases with multiple sampling. While this study describes LH/FSH in infants with DSD, the exact clinical role of the ratio in the management of these patients remains to be further elucidated.

HBM4EU feasibility studies: Lessons learned in combining health and human biomonitoring studies.

BACKGROUND: The European Human Biomonitoring Initiative (HBM4EU) is a joint program evaluating humans' exposure to several environmental substances and their potential health effects. One of the main objectives of HBM4EU is to make use of human biomonitoring (HBM) to assess human exposure to chemicals in Europe to better understand the associated health impacts and to improve chemical risk assessment. In parallel to HBM studies, health examination surveys (HESs), nutrition/dietary surveys, and disease specific health surveys are conducted in many European countries. In HESs, information collected by questionnaire(s) is supplemented with physical examinations and analysis of clinical and biological biomarkers in biological samples. HBM and health examination survey (HES) use similar data collection methods and infrastructures hence the feasibility of combining these two is explored in this paper. METHODS: Within HBM4EU, three feasibility studies (in Finland, Germany, and UK/England) were conducted to evaluate opportunities and obstacles of combining HBM and health studies. In this paper we report lessons learned from these feasibility studies. RESULTS: The Finnish feasibility study called KouBio-KUOPIO study was a new initiative without links to existing studies. The German feasibility study added a HBM module to the first follow-up examination of the LIFE-Adult-Study, a population-based cohort study. The UK feasibility integrates a sustainable HBM module into the Health Survey for England (HSfE), an annual health examination survey. Benefits of combining HBM and HESs include the use of shared infrastructures. Furthermore, participants can receive additional health information from HES, and participation rates tend to be higher due to the potential to obtain personal health information. Preparatory phases including obtaining ethical approval can be time-consuming and complicated. Recruitment of participants and low participation rates are common concerns in survey research and therefore designing user-friendly questionnaires with low participant burden is important. Unexpected events such as the COVID-19 pandemic can cause substantial challenges and delays for such studies. Furthermore, experiences from several countries demonstrated that long-term funding for combined studies can be difficult to obtain. CONCLUSIONS: In the future, incorporating HBM modules into existing HESs can provide a feasible and cost-effective method to conduct HBM studies and obtain a wide range of relevant data to support public health policies and research.

Testicular function is associated with cardiometabolic health markers: A cross-sectional study of 2289 young men.

BACKGROUND: Testicular function, including compensated Leydig cell function, has been indicated to be an early marker of morbidity. OBJECTIVE: To study the association of testicular function and markers of metabolic and cardiovascular health in a population of young men. MATERIALS AND METHODS: A cross-sectional study of 2289 men (median age 19 years, 5-95 percentile 18.4-22.2) from the general population examined between 2012 and 2019. Participants answered a questionnaire, had a blood sample drawn for assessment of reproductive hormone levels and health markers (lipids, glycosylated hemoglobin), delivered a semen sample, underwent physical examination including blood pressure measurements, and dual-energy X-ray absorptiometry scan for assessment of body composition. Associations were assessed in both crude and adjusted linear regression analyses. RESULTS: The men were within the normal reference intervals of their age for reproductive and health biomarkers. Compared to the lowest quartile, having luteinizing hormone levels in the highest quartile was associated with higher mean arterial pressure (1.6 [95% confidence interval: 0.8; 2.5] mmHg), cholesterol (0.1 [95% confidence interval: 0.02; 0.18] mmol/L), and total body fat percentage (1.1 [95% confidence interval: 0.4; 1.8] %-points). Higher serum testosterone levels were associated with more advantageous cardiometabolic health markers and higher total sperm count with a healthier body composition and lower glycosylated hemoglobin. DISCUSSION AND CONCLUSION: In this study of young men, unselected regarding reproductive hormones and semen quality, higher luteinizing hormone was associated with cardiovascular risk factors. Higher testosterone and total sperm count were associated with more favorable cardiometabolic indices. Thus, serum reproductive hormones and semen quality may be early appearing biomarkers of cardiovascular health even among young healthy men, which could potentially be useful for preventive initiatives to reduce the excess mortality and morbidity risk among infertile men. However, our study was cross-sectional and cannot determine causation. Future longitudinal studies of reproductive health in young men are warranted.

Prenatal exposure to phenols and benzophenones in relation to markers of male reproductive function in adulthood.

Introduction: Environmental exposure during fetal life may disrupt testicular development. In humans, a limited number of studies have investigated whether these adverse effects persist into adulthood. Using data from a prospective, population-based birth cohort study, The Copenhagen Mother-Child cohort, the objective was to assess if there is an association between fetal exposure to selected phenols and benzophenones and markers of testicular function in adult men. Methods: Pregnant women were recruited in 1997-2001. Their sons were examined clinically at 18-20 years of age, with focus on adult markers of reproductive function (anogenital distance (AGD), semen quality and reproductive hormones). In total, 101 18-20-year-old men were included, whose mothers during pregnancy had a serum sample drawn and analyzed for bisphenol A (BPA) and seven other simple phenols, as well as six benzophenones. To investigate the association between chemical levels (in tertiles, T1-T3) in relation to markers of reproductive function, univariate and multiple linear regression analyses were performed. Results: In fully adjusted analyses, increased levels of luteinizing hormone (LH) were observed with higher fetal exposure to BPA (percentage difference (95%CI)) (T2: 12% (-8%,36%) and T3: 33% (10%,62%), compared to T1) and benzophenone-3 (BP-3) (T2: 21% (-2%,49%), T3: 18% (-4%,45%)), while no clear association was seen to total testosterone (TT). Higher levels of BPA and BP-3 were associated with a lower TT/LH ratio, although only significant for BPA (p-trend=0.01). No associations were seen to AGD or markers of semen quality. Conclusion: In conclusion, high exposure to BPA and BP-3 was associated with a compensated reduced Leydig cell function but no other changes in markers of reproductive health. As maternal levels of BPA and BP-3 were not correlated, separate effects may be at play. Larger studies on long-term reproductive consequences of prenatal exposures are warranted to validate our findings.

Hypothesis: Metformin is a potential reproductive toxicant.

Metformin is the first-line oral treatment for type 2 diabetes mellitus and is prescribed to more than 150 million people worldwide. Metformin's effect as a glucose-lowering drug is well documented but the precise mechanism of action is unknown. A recent finding of an association between paternal metformin treatment and increased numbers of genital birth defects in sons and a tendency towards a skewed secondary sex ratio with less male offspring prompted us to focus on other evidence of reproductive side effects of this drug. Metformin in humans is documented to reduce the circulating level of testosterone in both men and women. In experimental animal models, metformin exposure in utero induced sex-specific reproductive changes in adult rat male offspring with reduced fertility manifested as a 30% decrease in litter size and metformin exposure to fish, induced intersex documented in testicular tissue. Metformin is excreted unchanged into urine and feces and is present in wastewater and even in the effluent of wastewater treatment plants from where it spreads to rivers, lakes, and drinking water. It is documented to be present in numerous freshwater samples throughout the world - and even in drinking water. We here present the hypothesis that metformin needs to be considered a potential reproductive toxicant for humans, and probably also for wildlife. There is an urgent need for studies exploring the association between metformin exposure and reproductive outcomes in humans, experimental animals, and aquatic wildlife.