Prenatal phthalate exposure and reproductive function in young men

Risk assessment of China's Eastern Route of the South-to-north Water Diversion Project from the perspective of Phthalate Esters occurrence in the impounded lakes

Phthalate esters (PAEs) are widely utilized and can accumulate in lacustrine ecosystems, posing significant ecological and human health hazards. Most studies on PAEs focus on individual lakes, lacking a comprehensive and systematic perspective. In response, we have focused our investigation on characteristic lakes situated along the Eastern Route of the South-to-north Water Diversion Project (SNWDP-ER) in China. We have detected 16 PAE compounds in the impounded lakes of the SNWDP-ER by collecting surface water samples using solid-phase extraction followed by gas chromatography analysis. The concentration of PAEs were found to between 0.80 to 12.92 μg L-1. Among them, Bis (2-ethylhexyl) phthalate (DEHP) was the most prevalent, with mean concentration of 1.56 ± 0.62 μg L-1 (48.44%), followed by Diisobutyl phthalate (DIBP), 0.64 ± 1.40 μg L-1 (19.87%). Spatial distribution showed an increasing trend in the direction of water flow. Retention of DEHP and DIBP has led to increased environmental risks. DEHP, Dimethyl phthalate (DMP) etc. determined by agriculture and human activities. Additionally, Dibutyl phthalate (DBP) and DIBP mainly related to the use of agricultural products. To mitigate the PAEs risk, focusing on integrated management of the lakes, along with the implementation of stringent regulations to control the use of plasticizes in products.

Multi-source exposure and health risks of phthalates among university students in Northeastern China

The endocrine disruptor phthalates (PAEs) are widely used as important chemical additives in a variety of areas around the globe. PAEs are toxic to reproduction and development and may adversely affect the health of adolescents. Risk assessments of exposure to PAEs from different sources are more reflective of actual exposure than single-source assessments. We used personal exposure parameters to estimate the dose of PAEs to 107 university students from six media (including dormitory dust, dormitory air, clothing, food, disposable food containers, and personal care products (PCPs)) and three exposure routes (including ingestion, inhalation, and dermal absorption). Individual factors and lifestyles may affect PAE exposure to varying degrees. Based on a positive matrix factorization (PMF) model, the results indicated that the main sources of PAEs in dust were indoor building materials and plastics, while PCPs and adhesives were the major sources of airborne PAEs. The relative contribution of each source to PAE exposure showed that food and air were the primary sources of dimethyl phthalate (DMP) and dibutyl phthalate (DBP). Air source contributed the most to diethyl phthalate (DEP) exposure, followed by PCPs. Food was the most significant source of diisobutyl phthalate (DiBP), benzyl butyl phthalate (BBP), and bis(2-ethylhexyl) phthalate (DEHP) exposure. Additionally, the exposure of DEHP to dust was not negligible. The ingestion pathway was the most dominant among the three exposure pathways, followed by dermal absorption. The non-carcinogenic risk of PAEs from the six sources was within acceptable limits. DEHP exhibits a low carcinogenic risk. We suggest university students maintain good hygienic and living habits to minimize exposure to PAEs.

Exposure to Paracetamol in Early Pregnancy and the Risk of Developing Cerebral Palsy: A Case-Control Study Using Serum Samples

OBJECTIVE

To investigate whether maternal paracetamol use in early pregnancy is associated with cerebral palsy (CP) in offspring.

STUDY DESIGN

We conducted a registry and biobank-based case-control study with mother-child pairs. We identified CP cases (n = 322) born between 1995 and 2014 from a nationwide CP-registry. Randomly selected controls (n = 343) and extra preterm controls (n = 258) were obtained from a birth registry. For each mother, a single serum sample from early pregnancy (gestation weeks 10-14) was retrieved from a biobank and analyzed for serum concentrations of paracetamol, categorized into unexposed (<1 ng/ml), mildly exposed (1-100 ng/ml), and highly exposed (>100 ng/ml), and in quartiles. Analyses were performed using logistic regression and adjusted for potential confounders. Separate analyses were conducted including only those children born preterm and only those born term.

RESULTS

Of the 923 participants, 36.8% were unexposed, 53.2% mildly exposed, and 10% highly exposed to paracetamol. Overall, prenatal exposure to paracetamol was not associated with CP. Sensitivity and subgroup analyses showed no clear associations between paracetamol and CP across strata of term/preterm birth as well as subtypes of CP.

CONCLUSIONS

The present study does not support an association between intrauterine exposure to paracetamol in early pregnancy and the risk of CP. However, it is important to stress that the exposure estimate is based on a single serum sample.

Cotinine concentrations in maternal serum and amniotic fluid during pregnancy and risk of testicular germ cell cancer in the offspring: A prospective nested case-control study

Maternal smoking in pregnancy may increase the risk of testicular germ cell cancer (TGCC) in offspring, but current evidence remains inconclusive. We performed a nested case-control study using cotinine measurements in maternal serum and amniotic fluid as a biomarker for tobacco exposure during pregnancy. A total of 654 males with maternal serum (n = 359, ncases/controls  = 71/288) and/or amniotic fluid (n = 295, ncases/controls  = 66/229) samples were included. Data on TGCC diagnoses and relevant covariates were derived from nationwide Danish health registries. Cotinine was quantified by liquid chromatography tandem mass spectrometry. An adapted cox regression model estimated the risk of TGCC considering active and inactive tobacco use defined according to cotinine concentrations of <, ≥15 ng/ml. Overall, the concentrations of cotinine were comparable in maternal serum and amniotic fluid (medianserum/amniotic fluid : 2.1/2.6 ng/ml). A strong statistically significant correlation was detected in 14 paired samples (Spearman rho: 0.85). Based on maternal serum cotinine concentrations, exposure to active tobacco use was not associated with risk of TGCC in offspring (HR 0.88, 95% CI 0.51; 1.52). Similarly, based on amniotic fluid cotinine concentrations, exposure to active tobacco use was not associated with risk of TGCC (HR 1.11, 95% CI 0.64; 1.95). However, different risks were observed for seminomas and nonseminomas in both matrices, but none were statistically significant. Our findings did not provide convincing evidence supporting that exposure to tobacco during pregnancy is associated with TGCC.

Exposure to per- and polyfluoroalkyl substances in early pregnancy and risk of cerebral palsy in children

BACKGROUND

Most cerebral palsy (CP) cases have an unexplained etiology, but a role for environmental exposures has been suggested. One purported environmental risk factor is exposure to endocrine-disrupting pollutants specifically per- and polyfluoroalkyl substances (PFAS).

OBJECTIVES

We investigated the association between prenatal PFAS exposures and CP in Swedish children.

METHODS

In this case-control study, 322 CP cases, 343 population controls, and 258 preterm controls were identified from a birth registry in combination with a CP follow-up program from 1995 to 2014 and linked to a biobank which contains serum samples from week 10-14 of pregnancy. Maternal serum concentrations of four PFAS compounds: perfluorohexane sulfonate (PFHxS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorooctane sulfonate (PFOS) were analyzed using liquid chromatography-tandem-mass-spectrometry. We estimated odds ratios (ORs) and 95 % confidence intervals (CIs) for CP and each PFAS in quartiles and as continuous variables controlling for various sociodemographic and lifestyle factors.

RESULTS

In crude and adjusted analyses, we did not find consistent evidence of associations between serum PFHxS, PFOA, PFNA, PFOS and concentrations in early pregnancy and CP, except in preterm infants. The ORs comparing the highest PFAS quartiles to the lowest were 1.05 (95 % CI: 0.63-1.76), 0.96 (95 % CI: 0.55-1.68), 0.71 (95 % CI: 0.41-1.25), and 1.17 (95 % CI: 0.61-2.26), for PFHxS, PFOA, PFNA, and PFOS, respectively. Some positive associations were observed for preterm infants, but the results were imprecise. Similar patterns were observed in analyses treating PFAS as continuous variables.

CONCLUSIONS

In this study, we found little evidence that early pregnancy prenatal exposure to PFHxS, PFOA, PFNA, or PFOS increases the risk of CP. However, some positive associations were observed for preterm cases and warrant further investigation.

Deteriorating Semen Quality: The Role of the Environment

Since the end of the last century, several reports have suggested that semen quality is declining, especially in Western countries. Furthermore, cross-sectional studies using similar protocols have suggested regional differences in semen quality of young and fertile men. Reasons for these regional differences and local adverse trends in semen quality are unknown, but environmental factors are suspected to have a role. Besides adulthood environmental exposures, those occurring during testicular development may also affect semen quality. Longitudinal follow-up studies and mixture risk analyses are needed to study the effect of fetal, childhood, and adult life environment on semen quality.

Assessing tobacco use in Swedish young adults from self-report and urinary cotinine: a validation study using the BAMSE birth cohort

OBJECTIVES

Studies on health effects of tobacco often rely on self-reported exposure data, which is subjective and can lead to misclassification. The aim of this study was to describe the prevalence of cigarette smoking, snus and e-cigarette use, as well as to validate self-reported tobacco use among young adults in Sweden.

METHOD

Participants of a population-based Swedish cohort (n=3052), aged 22-25 years, assessed their tobacco use in a web questionnaire. Urinary cotinine was analysed in a subsample of the study population (n=998). The agreement between self-reported tobacco use and urinary cotinine was assessed using Cohen's Kappa coefficient (κ) at a cut-off level of 50 ng/mL.

RESULTS

Patterns of tobacco use differed between men and women. Among men, 20.0% reported daily snus use, 5.8% daily cigarette smoking and 5.6% any e-cigarette use. In contrast, 3.2% of the women reported daily snus use, 9.0% daily cigarette smoking and 2.4% any e-cigarette use. Among the tobacco use categories, daily snus users had the highest levels of cotinine. Of reported non-tobacco users, 3.5% had cotinine levels above the cut-off, compared with 68.0% among both occasional cigarette smokers and snus users, 67.5% among all e-cigarette users and 94.7% and 97.8% among daily cigarette smokers and snus users, respectively. Agreement between self-reported tobacco use and urinary cotinine was classified as strong for daily use of cigarettes (κ=0.824) and snus (κ=0.861), while moderate to weak for occasional smoking (κ=0.618), occasional snus use (κ=0.573) and any e-cigarette use (κ=0.576).

CONCLUSIONS

We found high validity of self-reported tobacco use in our study population, particularly for daily tobacco use. Further, we found that daily snus users were exposed to high levels of cotinine. Together with previous findings, our results indicate good validity of self-reported tobacco use among young adults.

Mechanism of testicular injury induced by Di-ethylhexyl phthalate and its protective agents

Di-ethylhexyl phthalate (DEHP) is used as an important plasticizer in a wide range of products such as paints, food packaging, medical devices and children's toys. In recent years, there has been increasing interest in the toxic effects of DEHP on the male reproductive organs, the testicles. Here, we reviewed the basic pathways of testicular damage caused by DEHP. The mechanism involves oxidative stress, ferroptosis, interfering with hypothalamic-pituitary-gonadal axis (HPGA) and testosterone level. We summarized the protective agents that have been shown to be effective in repairing this type of testicular damage in recent years. This provides a new perspective and direction for future research into the health effects and molecular mechanisms of DEHP.

Maternal phthalate exposure during pregnancy and testis function of young adult sons

BACKGROUND

Phthalate exposure during fetal life may disrupt testicular development. Congruent with this, studies have found shorter anogenital distance, reduced penile size and altered hormone levels in infant boys whose mothers were exposed to higher levels of some phthalates during pregnancy. Few studies have explored if such adverse effects persist in adulthood. Thus, we aimed to explore if there is an association between fetal phthalate exposure and markers of testicular function in young adult men.

METHODS

In a longitudinal mother-child cohort from Copenhagen, Denmark, we examined 100 young men whose mothers during pregnancy had serum drawn and analyzed for 34 phthalate metabolites. Examinations of the young men took place at 18-20 years of age and included measurements of adult markers of testicular function (reproductive hormones, penile size, anogenital distance (AGD), testis volume, semen quality) and growth factors. Associations between maternal serum concentrations of phthalate metabolites and reproductive measures in the young men were tested using multiple linear regression.

RESULTS

Most consistently, higher maternal phthalate exposure was associated with higher luteinizing hormone (LH) but unchanged testosterone in adult sons. Congruently, higher maternal exposure was associated with lower total and free testosterone/LH ratios in adult sons. For example, twice as high maternal MiNP was associated with a 7.9 % (95 % CI 1.6-13.8) lower free testosterone/LH ratio. There was no consistent pattern of associations between the different phthalate metabolites and other reproductive hormones, clinical outcomes, or semen quality. None of the tested associations was significant after multiplicity adjustment.

CONCLUSIONS

In this exploratory study, higher maternal exposure to some phthalates was associated with impaired testicular Leydig cell function evidenced by a lower total and free testosterone/LH ratio in adult sons. This unique 18-20-year follow-up study raises concern and suggests that exposure of pregnant women to phthalates may have long-term effects on adult reproductive health in male offspring.

Environmental toxicants and male fertility

Semen quality has declined especially among Western men. Experimental and epidemiological studies have shown potential links between exposure to environmental toxicants and poor male fertility. Some environmental exposures in utero can disrupt fetal testicular function and result in cryptorchidism, low semen quality, low serum testosterone levels, and low fertility. Environmental exposure in childhood and adulthood can also adversely affect germ cells, Sertoli cells, Leydig cells, or the hypothalamic-pituitary-testicular axis, resulting in impaired male fertility. In this review, we report the latest results from human studies that investigated the role of endocrine disrupting chemicals, heavy metals, tobacco smoking, alcohol drinking, and use of marijuana in low semen quality and impaired male fertility. Current evidence suggests the relationship between these environmental factors and low male fertility; however, some factors showed conflicting results which need further investigation.

Effects of single or combined exposure to bisphenol A and mono(2-ethylhexyl)phthalate on oxidant/antioxidant status, endoplasmic reticulum stress, and apoptosis in HepG2 cell line

Endocrine disrupting chemicals (EDCs) may affect many biological processes like growth and stress response. Bisphenol A (BPA) is a plasticizer that is used to harden plastics and polycarbonates. Phthalates are used to add flexibility to polyvinyl chloride containing plastics. The main metabolite of di(2-ethylhexyl) phthalate (DEHP) is mono(2-ethylhexyl) phthalate (MEHP) and it is even more toxic than the parent compound. Humans are usually exposed to these chemicals in mixtures by different routes starting from fetal period. However, there are not many studies in literature that investigate the combined effects of these chemicals. The aim of this study is to investigate toxic effects of BPA and/or MEHP on HepG2 cell line. We have evaluated cytotoxicity, cytomorphological, apoptotic changes, oxidative stress, oxidant/antioxidant status alterations, and endoplasmic reticulum (ER) stress. Combined exposure to BPA and MEHP caused alterations in oxidant/antioxidant status and ER stress marker proteins in both cytoplasmic and nuclear cellular fractions. We can suggest that combined exposure to EDCs may cause serious toxicological outcomes and more mechanistic studies are needed to determine the combined toxic effects.

Nitrate in Maternal Drinking Water during Pregnancy and Measures of Male Fecundity in Adult Sons

Animal studies indicate deleterious effects of nitrate exposure on fecundity, but effects in humans are unknown, both for the prenatal and postnatal periods. We aimed to investigate if exposure to nitrate in maternal drinking water during the sensitive period of fetal life is associated with measures of fecundity in the adult sons. In a sub-analysis, the potential effects of nitrate exposure in adulthood were investigated. This cohort included 985 young adult men enrolled in The Fetal Programming of Semen Quality Cohort (FEPOS). Semen characteristics, testes volume and reproductive hormones were analyzed in relation to nitrate concentration in maternal drinking water, using a negative binomial regression model. The nitrate concentration in drinking water was obtained from monitoring data from Danish waterworks that were linked with the mothers' residential address during pregnancy. The median nitrate concentration in maternal drinking water was 2 mg/L. At these low exposure levels, which are far below the World Health Organization's (WHO) guideline value of 50 mg/L, we did not find indications of harmful effects of nitrate on the investigated measures of male fecundity.

Micro-contaminant, but immense impact: Source and influence of diethyl phthalate plasticizer on bottom-dwelling fishes

Sustainable plastic-waste management is becoming increasingly challenging as enormous loads of plastic debris regularly accumulate in susceptible ecosystems. The microplastic (MP) particles generated from these plastic wastes are imposing additional threats to these ecosystems due to their small size as well as their ability to adsorb and carry toxic chemicals. The current investigation deals with one such MP-originated toxicant, diethyl phthalate (DEP), and its impact on two species of freshwater loaches from the Western Ghats of India, Lepidocephalichthys thermalis and Indoreonectes evezardi. The MP samples were collected from the sediments of the Mula River and characterized using spectroscopic methods and scanning electron microscopy. Polymers, such as polyvinyl chloride and polypropylene, were identified in the collected MPs. GC-MS analysis of the MP extracts revealed the presence of DEP, confirming the MP waste as a potential source of DEP pollution. Further, to evaluate the effect of DEP on survival of selected loaches, L. thermalis and I. evezardi were exposed to DEP concentrations (18.75-300 mg L^-1) and the lethal DEP dose (LC₅₀) was estimated to be 44.53 mg L^-1 for L. thermalis and 34.64 mg L^-1 for I. evezardi. Fishes were further exposed to sub-lethal DEP concentration for one day (Short term exposure: STE) or eight days (Long term exposure: LTE) to analyze the histological condition and oxidative status of the liver in response to DEP treatment. Histology revealed congestion of sinusoids and vacuolization after the LTE. Higher lipid peroxidation levels were also measured in the livers of both species treated with DEP, which indicated DEP-mediated oxidative damage. The antioxidant enzymes including superoxide dismutase, catalase, peroxidase and glutathione-S-transferase displayed elevated activities in response to STE and LTE of DEP. Collectively, the results demonstrate that MPs in the Mula River are a potential source of DEP. The findings also show that DEP exposure can be fatal to freshwater fishes such as loaches, possibly by causing increased oxidative damage to the hepatic system.

Phthalate levels in prenatal and postnatal bedroom dust in the SELMA study

Phthalates are common in polyvinyl chloride (PVC) plastics and numerous consumer goods in our homes from which they can migrate and adhere to indoor dust particles. It is known that indoor dust exposure contribute to human phthalate intake; however, there is a lack of large studies with a repeated-measure design investigating how phthalate levels in indoor dust may vary over time in people's homes. This study investigated levels of seven phthalates and one alternative plasticiser di-iso-nonyl-cyclohexane-di-carboxylate (DiNCH) in bedroom dust collected prenatally around week 25 during pregnancy and postnatally at six months after birth, from 496 Swedish homes. Prenatal and postnatal phthalate levels were compared using correlation and season-adjusted general linear regression models. Over the nine-month period, levels of six out of seven phthalates were associated as indicated by a positive Pearson correlation (0.18 < r < 0.50, P < .001) and Lin's concordance correlation between matched prenatal and postnatal dust samples. Compared to prenatal levels, the season-adjusted postnatal levels decreased for five phthalates, whilst di-ethyl-hexyl phthalate (DEHP), di-2-propylheptyl phthalate (DPHP) and DiNCH increased. The results suggest that families with higher phthalate levels in bedroom dust during pregnancy are likely to remain among those with higher levels in the infancy period. However, all average phthalate levels changed over this specific nine-month period suggesting that available phthalate sources or their use were altered between the dust collections. Changes in home characteristics, family lifestyle, and phthalate replacement trends may contribute to explain the differences.

Risk factors on testicular function in adolescents

PURPOSE

Adolescence represents an important window for gonadal development. The aim of this review is to carry out a critical excursus of the most recent literature on endogenous and exogenous risk factors related to testicular function, focusing the research on adolescence period.

METHODS

A comprehensive literature search within PubMed was performed to provide a summary of currently available evidence regarding the impact on adolescence of varicocele, cryptorchidism, cancer, diabetes, lifestyle factors, endocrine disruptors, obesity and sexually transmitted diseases. We focused on human studies that evaluated a possible impact of these factors on puberty timing and their effects on andrological health.

RESULTS

Evidence collected seems to suggest that andrological health in adolescence may be impaired by several factors, as varicocele, cryptorchidism, and childhood cancer. Despite an early diagnosis and treatment, many adolescents might still have symptoms and sign of a testicular dysfunction in their adult life and at the current time it is not possible to predict which of them will experience andrological problems. Lifestyle factors might have a role in these discrepancies. Most studies point out towards a correlation between obesity, insulin resistance, alcohol, smoking, use of illegal drugs and testicular function in pubertal boys. Also, endocrine disruptors and sexually transmitted diseases might contribute to impair reproductive health, but more studies in adolescents are needed.

CONCLUSION

According to currently available evidence, there is an emerging global adverse trend of high-risk and unhealthy behaviors in male adolescents. A significant proportion of young men with unsuspected and undiagnosed andrological disorders engage in behaviors that could impair testicular development and function, with an increased risk for later male infertility and/or hypogonadism during the adult life. Therefore, adolescence should be considered a key time for intervention and prevention of later andrological diseases.

From Oxidative Stress to Male Infertility: Review of the Associations of Endocrine-Disrupting Chemicals (Bisphenols, Phthalates, and Parabens) with Human Semen Quality

Exposure to endocrine-disrupting chemicals (EDCs) may result in oxidative stress and endocrine system disturbance, which can have an impact on human reproduction and development. In male reproductive health, EDCs have been related to impaired reproductive function and male infertility, altered fetal development, and testicular germ-cell, prostate, and breast cancers. We conducted an electronic search using PubMed on endocrine disruptors related to oxidative stress and male infertility, and evaluated their association with endocrine-disrupting chemicals (bisphenols, phthalates, and parabens) in 25 articles. Higher levels of urinary bisphenols showed correlation with impaired semen quality and increased DNA damage. Considering phthalates and their metabolites, all studies found a positive association between urinary levels of phthalates and at least one semen parameter indicative of low semen quality; some studies also revealed sperm DNA damage. The studies on parabens less often revealed correlation of urinary parabens concentrations with a decrease in sperm count, as well as motility and DNA damage. Moreover, EDCs can elevate ROS production and lipid peroxidation, increase apoptosis, induce epigenetic modifications, and change the Y:X sperm chromosome ratio and sperm protein composition. Our review revealed detrimental effects of EDCs on semen quality and sperm DNA integrity-especially in BPA and phthalates, but also in parabens.

Effects of DEHP, DEHT and DINP Alone or in a Mixture on Cell Viability and Mitochondrial Metabolism of Endothelial Cells In Vitro

Plasticizers are chemicals in high demand, used in a wide range of commercial products. Human are exposed through multiple pathways, from numerous sources, to multiple plasticizers. This is a matter of concern, as it may contribute to adverse health effects. The vascular system carries plasticizers throughout the body and therefore can interact with the endothelium. The aim of the study was to evaluate the in vitro toxicity on endothelial cells by considering the individual and the mixture effects of bis-(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP) or bis-(2-ethylhexyl) terephthalate (DEHT). In this study, their cytotoxicity on HMEC-1 cells was evaluated on cell function (viability, cell counting, total glutathione and intracellular adenosines) and mitochondrial function (mitochondrial respiration). Results showed cellular physiological perturbations induced with all the condition tested, excepted for DEHT. Plasticizers induced a cytotoxicity by targeting mitochondrial respiration, depleting mitochondrial ATP production and increasing glycolytic metabolism. Additionally, delayed effects were observed between the cellular and the mitochondrial parameters. These results suggest that endothelial cells could go through a metabolic adaptation to face plasticizer-induced cellular stress, to effectively maintain their cellular processes. This study provides additional information on the adverse effects of plasticizers on endothelial cells.

Diffuse phthalate acid esters losses induced from large amount of agricultural plastic film residues caused low risks for water quality in China during 1991-2017

Extensive application of agricultural plastic films has resulted in abundant film residues in farmlands. Phthalate acid esters (PAEs) are vital additives of the agricultural plastic film and are easily emitted into soils. However, spatio-temporal variations of diffuse PAEs loss to water bodies have not been explored in China. This study used an integrated estimation framework and high-resolution activity data to conduct a comprehensive inventory of diffuse PAEs loss associated with plastic films of six main crop types in China for 1991-2017. We found that the diffuse PAEs loss induced from agricultural plastic films increased 10.57-46.30 kg over the same time. Di-butyl phthalate (DBP) and bis(2-ethylhexyl) phthalate (DEHP) accounted for ~75% of the national total loss. High PAEs loss regions are mainly located in Eastern China, the Middle-Lower Yangtze Plain, and eastern Yunnan and Sichuan provinces. We proved that PAEs emission, agricultural film residues, surface runoff, precipitation, and soil organic carbon explained 19.64%, 17.50%, 15.45%, 12.88%, and 9.83% of the total variation, respectively. The potential ecological risks to the various aquatic species were assessed to be low. Overall, our results are valuable for addressing severe agricultural plastic film residues and associated pollutant emissions and losses in China.

Decreased sperm counts in Swedish users of oral tobacco

Background

Smoke‐free tobacco via moist oral snuff (snus) is used daily in more than 20% of Swedish men. Negative effects of cigarette smoking on sperm parameters are well documented, unlike for snuff, despite relevance also for other smoke‐free nicotine products.

Objectives

We wanted to investigate whether reproductive parameters differed between users and non‐users of snuff, and whether the amount of snuff and nicotine exposure mattered.

Materials and methods

Men (n = 613) from the general population, recruited 2000–2010, were physically examined, answered questions on smoking and snuff use, and delivered urine, blood and semen samples. Sperm concentration, total sperm count, semen volume, percent morphologically normal and progressively motile sperm, and DNA fragmentation index (by the Sperm Chromatin Structure Assay) and reproductive hormones were analysed. Nicotine exposure was measured through urinary levels of cotinine. We used general linear models, with adjustments including cigarette smoking, and for semen parameters also abstinence time.

Results

After adjustments, total sperm count was 24% lower (P = 0.03) and testosterone 14% higher (P < 0.001) in 109 users of snuff than in non‐users, whereas cotinine was positively associated with testosterone and oestradiol (P < 0.001). Numbers of boxes of snuff used per week were associated with testosterone and FSH (P < 0.001).

Discussion

Applied to the general population, the consumption of smoke‐free tobacco by the use of snuff was associated with a lower sperm count and a higher testosterone, for which the extent seemed to play a role.

Conclusions

Independent of smoking, consumption of snuff was associated with lower total sperm count and different hormone levels. Applying these results to a reported association between sperm count and the chance of pregnancy, men who used snuff would have about a 10% lower chance of fathering a child.

Impacts of endocrine disrupting chemicals on reproduction in wildlife and humans

Endocrine disrupting chemicals (EDCs) are ubiquitous in aquatic and terrestrial environments. The main objective of this review was to summarize the current knowledge of the impacts of EDCs on reproductive success in wildlife and humans. The examples selected often include a retrospective assessment of the knowledge of reproductive impacts over time to discern how the effects of EDCs have changed over the last several decades. Collectively, the evidence summarized here within reinforce the concept that reproduction in wildlife and humans is negatively impacted by anthropogenic chemicals, with several altering endocrine system function. These observations of chemicals interfering with different aspects of the reproductive endocrine axis are particularly pronounced for aquatic species and are often corroborated by laboratory-based experiments (i.e. fish, amphibians, birds). Noteworthy, many of these same indicators are also observed in epidemiological studies in mammalian wildlife and humans. Given the vast array of reproductive strategies used by animals, it is perhaps not surprising that no single disrupted target is predictive of reproductive effects. Nevertheless, there are some general features of the endocrine control of reproduction, and in particular, the critical role that steroid hormones play in these processes that confer a high degree of susceptibility to environmental chemicals. New research is needed on the implications of chemical exposures during development and the potential for long-term reproductive effects. Future emphasis on field-based observations that can form the basis of more deliberate, extensive, and long-term population level studies to monitor contaminant effects, including adverse effects on the endocrine system, are key to addressing these knowledge gaps.

Urinary phthalate metabolites in pregnant women: occurrences, related factors, and association with maternal hormones

In this study, we aimed to evaluate phthalate metabolite levels in pregnant women, to explore the factors influencing exposure, and to assess phthalate metabolite levels in relation to thyroid hormone synthesis. We recruited 463 pregnant women and collected urine, blood, and questionnaire data at participant's first prenatal examination. Ten phthalate metabolites were analyzed: mono-isobutyl phthalate (MiBP); mono-methyl phthalate (MMP); mono-ethyl phthalate (MEP); mono-n-butyl phthalate (MnBP); mono-n-octyl phthalate (MOP); mono-benzyl phthalate (MBzP); and the metabolite of di-2-ethylhexyl phthalate (DEHP), which were mono (2-ethylhexyl) phthalate, mono-(2-ethyl-5-oxohexyl) phthalate, and mono-(2-ethyl-5-carboxypentyl) phthalate. Multivariable generalized estimating equation models and linear mixed models were used to predict urinary biomarker concentrations and to assess the associations between phthalate exposure and thyroid hormones. Positive associations were found between phthalate metabolites and lower education (MEP and MOP), living near the road (MEP, MnBP, and ∑DEHP), and consuming more puffed food (MEP and MBzP). In addition, MnBP (percent change [%△] = 4.25; 95% confidence interval [CI] = 0.32, 8.18) and ∑DEHP (%△ = 5.12; 95% CI = 1.25, 8.99) were positively associated with thyroid-stimulating hormones, although MEP and MnBP were inversely associated with free thyroxine and total triiodothyronine. Our findings suggest that certain habits and behaviors were predictive of the positive presence of phthalate metabolites and that certain phthalate esters are associated with altered thyroid hormone levels.

Fetal exposure to maternal cigarette smoking and male reproductive function in young adulthood

Maternal smoking during pregnancy constitutes a potential, major risk factor for adult male reproductive function. In the hitherto largest longitudinal cohort, we examined biomarkers of reproductive function according to maternal smoking during the first trimester and investigated whether associations were mitigated by smoking cessation prior to the fetal masculinization programming window. Associations between exposure to maternal smoking and semen characteristics, testicular volume and reproductive hormones were assessed among 984 young men from the Fetal Programming of Semen Quality (FEPOS) cohort. Maternal smoking was assessed through interview data and measured plasma cotinine levels during pregnancy. We applied negative binomial, logistic and linear regression models to estimate differences in outcomes according to levels of maternal smoking. Sons of light smokers (≤ 10 cigarettes/day) had a 19% (95% CI - 29%, - 6%) lower sperm concentration and a 24% (95% CI - 35%, - 11%) lower total sperm count than sons of non-smokers. These estimates were 38% (95% CI - 52%, - 22%) and 33% (95% CI - 51%, - 8%), respectively, for sons of heavy smokers (> 10 cigarettes/day). The latter group also had a 25% (95% CI 1%, 54%) higher follitropin level. Similarly, sons exposed to maternal cotinine levels of  > 10 ng/mL had lower sperm concentration and total sperm count. Smoking cessation prior to gestational week seven was not associated with a higher reproductive capacity. We observed substantial and consistent exposure-response associations, providing strong support for the hypothesis that maternal smoking impairs male reproductive function. This association persisted regardless of smoking cessation in early pregnancy.

Effects of prenatal and lactational bisphenol a and/or di(2-ethylhexyl) phthalate exposure on male reproductive system

Bisphenol A (BPA) and phthalates are abundantly used endocrine disrupting chemicals (EDCs). The aim of this study was to evaluate the effects of single and combined exposures to BPA and/or di(2-ethylhexyl) phthalate (DEHP) in prenatal and lactational period on rat male reproductive system in later stages of life. Pregnant Sprague-Dawley rats were divided randomly to four groups (n = 3/group): Control (corn oil); DEHP (30 mg/kg/day); BPA (50 mg/kg/day); and BPA+ DEHP (30 mg/kg/day DEHP and 50 mg/kg/day BPA). Groups exposed to EDCs through 6-21 gestational days and lactation period by intragastric lavage. Male offspring (n = 6/group) from each mother were fed till adulthood and were then euthanized. Later, reproductive hormones, sperm parameters, and oxidative stress parameters were determined. In conclusion, we can suggest that prenatal and lactational exposure to BPA and DEHP may cause adverse effects in male reproductive system in later stages of life especially after combined exposure.

Prenatal Exposures to Common Phthalates and Prevalent Phthalate Alternatives and Infant DNA Methylation at Birth

Phthalates are a diverse group of chemicals used in consumer products. Because they are so widespread, exposure to these compounds is nearly unavoidable. Recently, growing scientific consensus has suggested that phthalates produce health effects in developing infants and children. These effects may be mediated through mechanisms related to the epigenome, the constellation of mitotically heritable chemical marks and small compounds that guide transcription and translation. The present study examined the relationship between prenatal, first-trimester exposure of seven phthalates and epigenetics in two pregnancy cohorts (n = 262) to investigate sex-specific alterations in infant blood DNA methylation at birth (cord blood or neonatal blood spots). Prenatal exposure to several phthalates was suggestive of association with altered DNA methylation at 4 loci in males (all related to ΣDEHP) and 4 loci in females (1 related to ΣDiNP; 2 related to BBzP; and 1 related to MCPP) at a cutoff of q < 0.2. Additionally, a subset of dyads (n = 79) was used to interrogate the relationships between two compounds increasingly used as substitutions for common phthalates (ΣDINCH and ΣDEHTP) and cord blood DNA methylation. ΣDINCH, but not ΣDEHTP, was suggestive of association with DNA methylation (q < 0.2). Together, these results demonstrate that prenatal exposure to both classically used phthalate metabolites and their newer alternatives is associated with sex-specific infant DNA methylation. Research and regulatory actions regarding this chemical class should consider the developmental health effects of these compounds and aim to avoid regrettable substitution scenarios in the present and future.

Exposure to polycyclic aromatic hydrocarbons and nicotine, and associations with sperm DNA fragmentation

Background

Tobacco smoking has been reported to cause DNA fragmentation and has been suggested to cause mutations in spermatozoa. These effects have been ascribed to the action of polycyclic aromatic hydrocarbons (PAH) present in the smoke. Simultaneously, DNA fragmentation has been associated with mutagenesis.

Objective

The aim of this study was to investigate whether levels of urinary biomarkers of PAH and nicotine exposure were associated with sperm DNA fragmentation.

Methods

In the urine of 381 men recruited from two cohorts of young men (17–21 years old) from the general Swedish population, the PAH metabolites 1‐hydroxypyrene and 2‐hydroxyphenanthrene, as well as the nicotine metabolite cotinine, were measured. The sperm DNA fragmentation index (DFI) was analysed using the sperm chromatin structure assay. Associations between the DFI, and PAH metabolite levels as continuous variables as well as in quartiles, were studied by general linear models adjusted for abstinence time. A similar analysis was carried out for cotinine levels, according to which the men were categorised as “non‐smoking” (n = 216) and “smoking” (n = 165).

Results

No association was found between levels of any of the three biomarkers and DFI, either as a continuous variable (p = 0.87–0.99), or when comparing the lowest and the highest quartiles (p = 0.11–0.61). The same was true for comparison of men categorised as non‐smoking or smoking (DFI 11.1% vs. 11.8%, p = 0.31).

Discussion

We found no evidence of PAH or nicotine exposure to be associated with DFI, which does not exclude that these exposures may have other effects on sperm DNA.

Conclusion

In these young men, levels of biomarkers of nicotine and PAH exposure were not associated with DFI.

Prenatal phthalate exposure and early childhood wheeze in the SELMA study

BACKGROUND

Prenatal maternal phthalate exposure has been associated with wheeze and asthma in children, but results are inconclusive. Previous studies typically assessed exposure in late pregnancy, included only a small number of old phthalates, and assessed outcomes in children aged 5 years or older.

OBJECTIVE

We explored associations between 1st trimester prenatal maternal exposure to a wider range of phthalates and wheeze in early childhood.

METHODS

First trimester concentrations of 14 metabolites from 8 phthalates and one alternative plasticizer were quantified in first-morning void urine from 1148 mothers in the Swedish SELMA study. Associations between log-transformed metabolite concentrations and parental reported ever wheeze among 24-month-old children were investigated with logistic regression models adjusted for parental asthma/rhinitis, sex of child, maternal education, smoking, and creatinine.

RESULTS

Metabolites of replacement phthalates di-iso-decyl phthalate (DiDP) and di-2-propylheptyl phthalate (DPHP) were associated with increased risk for wheeze (aOR 1.47, 95% CI 1.08-2.01 and aOR 1.49, 95% CI 1.04-2.15, respectively). The associations with DiDP and DPHP were stronger among children whose parents did not have asthma or rhinitis. In this group, wheeze was also associated with metabolites of butyl-benzyl phthalate (BBzP) and di-iso-nonyl phthalate (DiNP).

SIGNIFICANCE

Maternal phthalate exposure during early pregnancy may be a risk factor for wheeze in early childhood, especially among children whose parents do not have asthma or rhinitis symptoms.

Gut microbiota may contribute to the postnatal male reproductive abnormalities induced by prenatal dibutyl phthalate exposure

Phthalate is an environmental endocrine disruptor that causes direct and intergenerational male reproductive damage. However, its mechanisms require further investigation. The role of gut microbiota in male reproductive function has been gradually revealed in the past. To explore the intergenerational testicular injury and the influence on offspring gut microbiota of the widely used phthalate dibutyl phthalate (DBP), we conducted a prenatal DBP exposure experiment with microbiota sequencing. We finally explained the gestational DBP exposure-induced gut dysbacteriosis, which is one of the mechanisms of testicular injury in the offspring. The occurrence of seminiferous atrophy and spermatogenic cells apoptosis showed a slight increase. Our study partially supported the results of previous research works on the characteristics of gut dysbacteriosis, which featured the increased relative abundance of Bacteroidetes, Prevotella and P. copri. Focusing on the role of gut microbiota in reproductive function is important. Future studies need to investigate the relationship between environmental pollution and human health.

Phthalate metabolites: Characterization, toxicities, global distribution, and exposure assessment

Phthalates are plasticizers in various products and regarded as endocrine disruptors due to their anti-androgen effects. Environmental occurrence and toxicities of parent phthalates have been widely reported, while the current state of knowledge on their metabolites is rarely summarized. Based on the available literature, the present review mainly aims to 1) characterize the potential metabolites of phthalates (mPAEs) using the pharmacokinetics evidences acquired via animal or human models; 2) examine the molecular and cellular mechanism involved in toxicity for mPAEs; 3) investigate the exposure levels of mPAEs in different human specimens (e.g., urine, blood, seminal fluid, breast milk, amniotic fluid and others) across the globe; 4) discuss the models and related parameters for phthalate exposure assessment. We suggest there is subtle difference in toxic mechanisms for mPAEs compared to their parent phthalates due to their alternative chemical structures. Human monitoring studies performed in Asia, America and Europe have provided the population exposure baseline levels for typical phthalates in different regions. Urine is the preferred matrix than other specimens for phthalate exposure study. Among ten urinary mPAEs, the largest proportions of di-(2-ethylhexyl) phthalate (DEHP) metabolites (40%), monoethyl phthalate (mEP) (43%) and DEHP metabolites/mEP (both 29%) were observed in Asia, America and Europe respectively, and mono-5-carboxy-2-ethypentyl phthalate was the most abundant compounds among DEHP metabolites. Daily intakes of phthalates can be accurately calculated via urinary mPAEs if the proper exposure parameters were determined. Further work should focus on combining epidemiological and biological evidences to establish links between phthalates exposure and biological phenotypes. More accurate molar fractions (F_UE) of the urinary excreted monoester related to the ingested diesters should be collected in epidemiological or pharmacokinetic studies for different population.

Phthalates and Alternative Plasticizers Differentially affect Phenotypic Parameters in Gonadal Somatic and Germ Cell Lines

The developmental and reproductive toxicity associated with exposure to phthalates has motivated a search for alternatives. However, there is limited knowledge regarding the adverse effects of some of these chemicals. We used high-content imaging to compare the effects of mono (2-ethylhexyl) phthalate (MEHP) with six alternative plasticizers: di-2-ethylhexyl terephthalate (DEHTP); diisononyl-phthalate (DINP); di-isononylcyclohexane-1,2-dicarboxylate (DINCH); 2-ethylhexyl adipate (DEHA); 2,2,4-trimethyl 1,3-pentanediol diisobutyrate (TXIB) and di-iso-decyl-adipate (DIDA). A male germ spermatogonial cell line (C18-4), a Sertoli cell line (TM4) and two steroidogenic cell lines (MA-10 Leydig and KGN granulosa) were exposed for 48h to each chemical (0.001-100 μM). Cell images were analyzed to assess cytotoxicity and effects on phenotypic endpoints. Only MEHP (100 μM) was cytotoxic and only in C18-4 cells. However, several plasticizers had distinct phenotypic effects in all four cell lines. DINP increased Calcein intensity in C18-4 cells, whereas DIDA induced oxidative stress. In TM4 cells, MEHP, and DINCH affected lipid droplet numbers, while DEHTP and DINCH increased oxidative stress. In MA-10 cells, MEHP increased lipid droplet areas and oxidative stress; DINP decreased the number of lysosomes, while DINP, DEHA and DIDA altered mitochondrial activity. In KGN cells, MEHP, DINP and DINCH increased the number of lipid droplets, whereas DINP decreased the number of lysosomes, increased oxidative stress and affected mitochondria. The Toxicological Priority Index (ToxPi) provided a visual illustration of the cell line specificity of the effects on phenotypic parameters. The lowest administered equivalent doses were observed for MEHP. We propose that this approach may assist in screening alternative plasticizers.

Indoor phthalate exposure and contributions to total intake among pregnant women in the SELMA study

Phthalates are widely used in consumer products. Exposure to phthalates can lead to adverse health effects in humans, with early-life exposure being of particular concern. Phthalate exposure occurs mainly through ingestion, inhalation, and dermal absorption. However, our understanding of the relative importance of different exposure routes is incomplete. This study estimated the intake of five phthalates from the residential indoor environment for 455 Swedish pregnant women in the SELMA study using phthalate mass fraction in indoor dust and compares these to total daily phthalate intakes back-calculated from phthalate metabolite concentrations in the women's urine. Steady-state models were used to estimate indoor air phthalate concentrations from dust measurements. Intakes from residential dust and air made meaningful contributions to total daily intakes of more volatile di-ethyl phthalate (DEP), di-n-butyl phthalate (DnBP), and di-iso-butyl phthalate (DiBP) (11% of total DEP intake and 28% of total DnBP and DiBP intake combined). Dermal absorption from air was the dominant pathway contributing to the indoor environmental exposure. Residential exposure to less volatile phthalates made minor contributions to total intake. These results suggest that reducing the presence of low molecular weight phthalates in the residential indoor environment can meaningfully reduce phthalate intake among pregnant women.

Associations of prenatal exposure to phthalates and one phthalate substitute with anthropometric measures in early life: Results from the German LIFE Child cohort study

Exposure to phthalates is widespread and especially early life stages represent a critical window of exposure. In the present study, we investigated the effect of prenatal exposure to phthalates on birth outcomes and weight development in early life. In 130 mother-child pairs, we estimated the association of concentrations of 13 phthalates in spot-urine samples collected during pregnancy and birth outcomes and weight gain in the first two years of life using robust linear regression. High molecular weight phthalates were inversely associated with birth weight in girls but not in boys. Thus, prenatal exposure to phthalates may affect birth weight in a sex-specific manner.

Maternal occupational exposure to endocrine-disrupting chemicals during pregnancy and semen parameters in adulthood: results of a nationwide cross-sectional study among Swiss conscripts

STUDY QUESTION

Is there a relationship between maternal occupational exposure to endocrine-disrupting chemicals (EDCs) during pregnancy and the semen quality of their sons?

SUMMARY ANSWER

Our results suggest an association between maternal occupational exposure to potential EDCs, especially to pesticides, phthalates and heavy metals, and a decrease in several semen parameters.

WHAT IS KNOWN ALREADY

Sexual differentiation, development and proper functioning of the reproductive system are largely dependent on steroid hormones. Although there is some animal evidence, studies on maternal exposure to EDCs during pregnancy and its effect on the semen quality of sons are scarce and none have focused on maternal occupational exposure.

STUDY DESIGN, SIZE, DURATION

A cross-sectional study aiming to evaluate semen quality was carried out among Swiss conscripts aged 18 to 22 years between 2005 and 2017.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Conscript and parent questionnaires were completed prior to the collection of a semen sample. Semen parameters were categorised according to the guidelines of the World Health Organization (WHO). Data on maternal employment during pregnancy were provided by the parent questionnaire. Maternal occupational exposure to potential EDC categories was defined using a job-exposure matrix (JEM). Logistic regressions were used to analyse the relationship between maternal occupational exposure to EDCs and each semen parameter adjusted for potential confounding factors. Results are presented using odds ratios and 95% confidence intervals.

MAIN RESULTS AND THE ROLE OF CHANCE

In total, 1,737 conscripts provided a conscript and parent questionnaire, as well as a semen sample; among these 1,045 of their mothers worked during pregnancy. Our study suggests an association between occupational exposure of mothers during pregnancy to potential EDCs and low semen volume and total sperm count, particularly for exposure to pesticides (OR 2.07, 95% CI 1.11-3.86 and OR 2.14, 95% CI 1.05-4.35), phthalates (OR 1.92, 95% CI 1.10-3.37 and OR 1.89, 95% CI 1.01-3.55), and heavy metals (OR 2.02, 95% CI 1.14-3.60 and OR 2.29, 95% CI 1.21-4.35). Maternal occupational exposure to heavy metals was additionally associated with a low sperm concentration (OR 1.89, 95% CI 1.06-3.37).

LIMITATIONS, REASONS FOR CAUTION

Several limitations should be noted, such as the indirect method for maternal occupational exposure assessment during the pregnancy (JEM) and the cross-sectional design of the study.

WIDER IMPLICATIONS OF THE FINDINGS

Our observations reinforce the need to inform pregnant women of potential hazards during pregnancy that could impair their child's fertility. Additional studies are needed to confirm the involvement of EDCs.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the Swiss Centre for Applied Human Toxicology: SCAHT and the 'Fondation privée des Hôpitaux Universitaires de Genève'. The collection of human biological material used for this study was supported by the FABER Foundation, the Swiss National Science Foundation (SNSF): NFP 50 'Endocrine Disruptors: Relevance to Humans, Animals and Ecosystems', the Medical Services of the Swiss Army (DDPS) and Medisupport. The authors declare they have no competing financial interests.

TRIAL REGISTRATION NUMBER

N/A.

Exploring the evidence for epigenetic regulation of environmental influences on child health across generations

Environmental exposures, psychosocial stressors and nutrition are all potentially important influences that may impact health outcomes directly or via interactions with the genome or epigenome over generations. While there have been clear successes in large-scale human genetic studies in recent decades, there is still a substantial amount of missing heritability to be elucidated for complex childhood disorders. Mounting evidence, primarily in animals, suggests environmental exposures may generate or perpetuate altered health outcomes across one or more generations. One putative mechanism for these environmental health effects is via altered epigenetic regulation. This review highlights the current epidemiologic literature and supporting animal studies that describe intergenerational and transgenerational health effects of environmental exposures. Both maternal and paternal exposures and transmission patterns are considered, with attention paid to the attendant ethical, legal and social implications.

Effects of endocrine disruptors on fetal testis development, male puberty, and transition age

PURPOSE

Endocrine disruptors (EDs) are exogenous substances able to impair endocrine system; consequently, they may cause numerous adverse effects. Over the last years, particular focus has been given to their harmful effects on reproductive system, but very little is known, especially in males. The aim of this review is to discuss the detrimental effects of EDs exposure on fetal testis development, male puberty, and transition age.

METHODS

A search for the existing literature focusing on the impact of EDs on fetal testis development, male puberty, andrological parameters (anogenital distance, penile length, and testicular volume), and testicular cancer with particular regard to pubertal age provided the most current information available for this review. Human evidence-based reports were given priority over animal and in vitro experimental results. Given the paucity of available articles on this subject, all resources were given careful consideration.

RESULTS

Information about the consequences associated with EDs exposure in the current literature is limited and often conflicting, due to the scarcity of human studies and their heterogeneity.

CONCLUSIONS

We conclude that current evidence does not clarify the impact of EDs on human male reproductive health, although severe harmful effects had been reported in animals. Despite controversial results, overall conclusion points toward a positive association between exposure to EDs and reproductive system damage. Further long-term studies performed on wide number of subjects are necessary in order to identify damaging compounds and remove them from the environment.

Risk Assessment of Agricultural Plastic Films Based on Release Kinetics of Phthalate Acid Esters

Plastic films have become an integral part of fruit and vegetable production systems, but their release of phthalate acid esters (PAEs) is a threat to human health. The release kinetics of PAEs and measures of risk are still not well understood. We investigated 50 agricultural films, with concentrations ranging from 2.59 to 282,000 mg kg^-1. The seven commercially available film types included were polyvinylchloride (PVC), metallocene polyethylene (mPE), ethylene vinyl acetate (EVA), polyolefin (PO), and three mulch films. Bis(2-ethylhexyl) phthalate (DEHP) was detected in most of films, and its release fitted well into the first-order kinetic model. The release rate of DEHP was negatively related to the film thickness. The potential carcinogenic risks of DEHP in the air of six kinds of plastic greenhouses to human health were estimated. We found that the carcinogenic risks associated with PVC and mPE greenhouse films warrant greater attention. Though EVA, PO greenhouse, and mulch films were lower risk, we advise keeping plastic greenhouses well ventilated during the first month of use to reduce direct human exposure to volatile PAEs.

The Assessment of the Sewage and Sludge Contamination by Phthalate Acid Esters (PAEs) in Eastern Europe Countries

Phthalate acid esters (PAEs) are widely used as raw materials for industries that are well known for their environmental contamination and toxicological effects as “endocrine disruptors”. The determining of PAE contamination was based on analysis of dimethyl phthalate (DMP), diethyl phthalate (DEP), dipropyl phthalate (DPP), dibutyl phthalate (DBP), diisobutyl phthalate (DiBP), dicyclohexyl phthalate (DCHP) and di(2-ethylhexyl) phthalate (DEHP) in wastewater and sediment samples collected from city sewer systems of Lithuania and Poland, and Denmark for comparison. The potential PAE sources as well as their concentrations in the wastewater were analyzed and discussed. The intention of the study was to determine the level and key sources of pollution by phthalates in some Eastern European countries and to reveal the successful managerial actions to minimize PAEs taken by Denmark. Water and sludge samples were collected in 2019–2020 and analyzed by gas chromatography-mass spectrometry. The highest contamination with phthalates in Lithuania can be attributed to DEHP: up to 63% of total PAEs in water samples and up to 94% of total PAEs in sludge samples, which are primarily used as additive compounds to plastics but do not react with them and are gradually released into the environment. However, in water samples in Poland, the highest concentration belonged to DMP—up to 210 μg/L, while the share of DEHP reached 15 μg/L. The concentrations of priority phthalate esters in the water samples reached up to 159 μg/L (DEHP) in Lithuania and up to 1.2 μg/L (DEHP) in Denmark. The biggest DEHP concentrations obtained in the sediment samples were 95 mg/kg in Lithuania and up to 6.6 mg/kg in Denmark. The dominant compounds of PAEs in water samples of Lithuania were DEHP > DEP > DiBP > DBP > DMP. DPP and DCHP concentrations were less than 0.05 μg/L. However, the distribution of PAEs in the water samples from Poland was as follows: DMP > DEHP > DEP > DBP, and DiBP, as well as DPP and DCHP, concentrations were less than 0.05 μg/L. Further studies are recommended for adequate monitoring of phthalates in wastewater and sludge in order to reduce or/and predict phthalates’ potential risk to hydrobiots and human health.

Endocrine Disrupting Chemicals and Reproductive Health in Boys and Men

Male reproductive health has declined as indicated by increasing rates of cryptorchidism, i.e., undescended testis, poor semen quality, low serum testosterone level, and testicular cancer. Exposure to endocrine disrupting chemicals (EDCs) has been proposed to have a role in this finding. In utero exposure to antiandrogenic EDCs, particularly at a sensitive period of fetal testicular development, the so-called 'masculinization programming window (MPW)', can disturb testicular development and function. Low androgen effect during the MPW can cause both short- and long-term reproductive disorders. A concurrent exposure to EDCs may also affect testicular function or damage testicular cells. Evidence from animal studies supports the role of endocrine disrupting chemicals in development of male reproductive disorders. However, evidence from epidemiological studies is relatively mixed. In this article, we review the current literature that evaluated relationship between prenatal EDC exposures and anogenital distance, cryptorchidism, and congenital penile abnormality called hypospadias. We review also studies on the association between early life and postnatal EDC exposure and semen quality, hypothalamic-pituitary-gonadal axis hormone levels and testicular cancer.

Endocrine Disruption: Structural Interactions of Androgen Receptor against Di(2-ethylhexyl) Phthalate and Its Metabolites

Diethylhexyl phthalate (DEHP) is a commonly used plasticizer in the manufacture of polyvinyl chloride plastics for household and commercial use. DEHP is a ubiquitous ecocontaminant and causes developmental and reproductive problems in children and adults. After exposure, DEHP is metabolized by endogenous hydrolysis and oxidation into the primary metabolite, mono-(2-ethylhexyl) phthalate (MEHP), and the secondary metabolites, mono-(2-ethyl-5-hydroxhexyl)phthalate (5-OH-MEHP), mono-(2-ethyl-5-oxohexyl) phthalate (5-oxo-MEHP), mono-(2-ethyl-5-carboxypentyl) phthalate (5-cx-MEPP), and mono-[(2-carboxymethyl)hexyl] phthalate (2-cx-MMHP). Very few studies have been reported on the adverse effects of DEHP metabolites, and the available information indicates that the metabolites might also be equally or more active as compared to the parent compound. In the present study, induced fit docking was used for structural binding characterization of the above five DEHP metabolites with androgen receptor (AR) to predict the potential endocrine-disrupting effects of these metabolites in AR signaling. All the DEHP metabolites interacted with the ligand-binding pocket of AR forming amino-acid residue interactions, hydrogen bonding, and pi-pi interactions. The binding energy of DEHP with AR was similar to that of native ligand testosterone. The amino-acid residue interactions of DEHP metabolites had 91-100% similarity compared to that of testosterone. In addition, all the DEHP metabolites and testosterone showed a common hydrogen bonding interaction with amino-acid Arg-752 of AR. Taken together, the structural binding data in the present study suggested the potential for DEHP metabolites to disrupt AR signaling, which may lead to androgen-related reproductive dysfunction.

The effects of the phthalate DiNP on reproduction†

Di-isononyl phthalate (DiNP) is a high molecular weight, general purpose, plasticizer used primarily in the manufacture of polymers and consumer products. It can be metabolized rapidly and does not bioaccumulate. The primary metabolite of DiNP is monoisononyl-phthalate (MiNP) and the secondary metabolites include three oxidative derivatives of DiNP, which have been identified mainly in urine: mono-oxoisononyl phthalate (MOINP or oxo-MiNP), mono-carboxyisooctyl phthalate (MCIOP, MCOP or cx-MiNP), and mono-hydroxyisononyl phthalate (MHINP or OH-MiNP). The secondary metabolites are very sensitive biomarkers of DiNP exposure while primary metabolites are not. As the usage of DiNP worldwide increases, studies evaluating its potential reproductive toxicity are becoming more prevalent in the literature. In studies on female animals, the researchers found that the exposure to DiNP appears to induce negative effects on ovarian function and fertility in animal models. Whether or not DiNP has direct effects on the uterus is still controversial, and the effects on human reproduction require much more research. Studies on males indicate that DiNP exposure has disruptive effects on male reproduction and fertility. Occupational studies also indicate that the exposure to DiNP might induce negative effects on male reproduction, but larger cohort studies are needed to confirm this. This review presents an overview of the literature regarding the reproductive effects of exposure to DiNP.

Regional difference in semen quality of young men: a review on the implication of environmental and lifestyle factors during fetal life and adulthood

The prevalence of low semen quality and the incidence of testicular cancer have been steadily increasing over the past decades in different parts of the World. Although these conditions may have a genetic or epigenetic origin, there is growing evidence that multiple environmental and lifestyle factors can act alone or in combination to induce adverse effects. Exposure to these factors may occur as early as during fetal life, via the mother, and directly throughout adulthood after full spermatogenic capacity is reached. This review aims at providing an overview of past and current trends in semen quality and its relevance to fertility as well as a barometer of men’s general health. The focus will be on recent epidemiological studies of young men from the general population highlighting geographic variations in Europe. The impact of some lifestyle and environmental factors will be discussed with their role in both fetal life and adulthood. These factors include smoking, alcohol consumption, psychological stress, exposure to electromagnetic radiation, and Endocrine Disrupting Chemicals (EDCs). Finally, the challenges in investigating the influence of environmental factors on semen quality in a fast changing world are presented.

An update on the hazard of and exposure to diethyl hexyl phthalate (DEHP) alternatives used in medical devices

The use of the plasticizer diethyl hexyl phthalate (DEHP) in PVC medical devices is being questioned due to its potential reprotoxic effects in patients exposed as a result from migration from the device. This article reviews new information on migration and toxicity data of eleven alternative plasticizers that have previously been evaluated by the Danish EPA and the EU SCENIHR (Scientific Committee on Emerging and Newly Identified Health Risks). The new toxicity data did not justify the reconsideration of the critical NOAELs as established by SCENIHR and Danish EPA. The dataset on oral toxicity studies is rather complete for most substances; however, in particular for reproductive toxicity and endocrine disruption, data gaps still exist for many alternatives. Toxicity data on intravenous exposure are lacking and these are essential to conclude on hazard characteristics of alternatives that are poorly absorbed via the oral exposure route. Migration data are emerging for a few alternatives but still sparse for the majority of the alternatives. Taking all data on migration and toxicity in consideration, 1,2-cyclohexanedicarboxylic acid, diisononylester (DINCH), and tris(2-ethylhexyl)benzene-1,2,4-tricarboxylate display a more favorable profile compared to DEHP. For these promising alternatives, a risk assessment for use in medical devices should be conducted. As a next step, we recommend the (further) generation of relevant migration data and, where needed, relevant toxicity data for the alternative substances, in order to be able to conduct a benefit-risk analysis of DEHP and the alternatives as obligatory in the new European Union Medical Device Regulation.

Determination of phthalates in fish fillets by liquid chromatography tandem mass spectrometry (LC-MS/MS): A comparison of direct immersion solid phase microextraction (SPME) versus ultrasonic assisted solvent extraction (UASE)

Due to the increasing presence of plastic and plastic associated contaminants in the aquatic environments, the monitoring of this contamination in fish products and the understanding of possible human health implications is considered urgent. However, data are still relatively scarce, mostly due to the methodological challenges in the chemical analysis: these contaminants are ubiquitous and procedural contamination from the laboratory is frequent. In this work, we compared solid-phase microextraction (SPME) to ultrasonic assisted solvent extraction (UASE) as sample preparation methods for the liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) determination of phthalates in fish fillets. UASE was carried out with an acetone-hexane (1:1) solution and according to a reference procedure aimed to obtain the exhaustive extraction of the target analytes. SPME was carried out by applying C18 fibers in direct immersion mode and by using water/methanol 20:80 mixture to desorb the aliquot required for the analysis. Overall, SPME displayed an improved control of the background contamination and enabled lower LOQs. Precision, calculated as relative standard deviation (RSD) on replicates of a reference sample, was below 24% for both the method. Analysis of real samples purchased from Italian supermarkets showed that SPME might be an efficient tool for estimating the risk associated with fish consumption.

Endocrine-disrupting chemicals: implications for human health

Since reports published in 2015 and 2016 identified 15 probable exposure-outcome associations, there has been an increase in studies in humans of exposure to endocrine-disrupting chemicals (EDCs) and a deepened understanding of their effects on human health. In this Series paper, we have reviewed subsequent additions to the literature and identified new exposure-outcome associations with substantial human evidence. Evidence is particularly strong for relations between perfluoroalkyl substances and child and adult obesity, impaired glucose tolerance, gestational diabetes, reduced birthweight, reduced semen quality, polycystic ovarian syndrome, endometriosis, and breast cancer. Evidence also exists for relations between bisphenols and adult diabetes, reduced semen quality, and polycystic ovarian syndrome; phthalates and prematurity, reduced anogenital distance in boys, childhood obesity, and impaired glucose tolerance; organophosphate pesticides and reduced semen quality; and occupational exposure to pesticides and prostate cancer. Greater evidence has accumulated than was previously identified for cognitive deficits and attention-deficit disorder in children following prenatal exposure to bisphenol A, organophosphate pesticides, and polybrominated flame retardants. Although systematic evaluation is needed of the probability and strength of these exposure-outcome relations, the growing evidence supports urgent action to reduce exposure to EDCs.

Fetal Programming of Semen Quality (FEPOS) Cohort - A DNBC Male-Offspring Cohort

BACKGROUND

Prenatal exposures may contribute to male infertility in adult life, but large-scale epidemiological evidence is still lacking. The Fetal Programming of Semen quality (FEPOS) cohort was founded to provide means to examine if fetal exposures can interfere with fetal reproductive development and ultimately lead to reduced semen quality and reproductive hormone imbalances in young adult men.

METHODS

Young adult men at least 18 years and 9 months of age born to women in the Danish National Birth Cohort living in relative proximity to Copenhagen or Aarhus and for whom a maternal blood sample and two maternal interviews during pregnancy were available were invited to FEPOS. Recruitment began in March 2017 and ended in December 2019. The participants answered a comprehensive questionnaire and underwent a physical examination where they delivered a semen, urine, and hair sample, measured their own testicular volume, and had blood drawn.

RESULTS

In total 21,623 sons fulfilled eligibility criteria of whom 5697 were invited and 1058 participated making the response rate 19%. Semen characteristics did not differ between sons from the Copenhagen and Aarhus clinics. When comparing the FEPOS semen parameters to similar cohorts, the median across all semen characteristics was slightly lower for FEPOS participants, although with smaller variation.

CONCLUSION

With its 1058 young adult men, the FEPOS cohort is the largest population-based male-offspring cohort worldwide specifically designed to investigate prenatal determinants of semen quality. Wide-ranging information on maternal health, lifestyle, socioeconomic status, occupation, and serum concentrations of potential reproductive toxicants during pregnancy combined with biological markers of fertility in their sons collected after puberty allow for in-depth investigations of the 'fetal origins of adult disease hypothesis'.

Phthalates and Sex Steroid Hormones Among Men From NHANES, 2013-2016

CONTEXT

Phthalates are commonly found in commercial packaging, solvents, vinyl, and personal care products, and there is concern for potential endocrine-disrupting effects in males. The commonly used di-2-ethylhexyl phthalate (DEHP) has progressively been replaced by seldom studied compounds, such as bis-2-ethylhexyl terephthalate and 1,2-cyclohexane dicarboxylic acid di-isononyl ester (DINCH).

OBJECTIVE

To investigate the associations between the urinary phthalate metabolites and serum sex steroid hormone concentrations in a nationally representative sample of adult males.

DESIGN, SETTING, PARTICIPANTS, AND INTERVENTION

This was a cross-sectional analysis of data from the 2013-2016 National Health and Nutrition Examination Survey among 1420 male participants aged ≥20 years.

MAIN OUTCOME MEASURES

Serum levels of total testosterone, estradiol, SHBG, and derived sex hormone measurements of free testosterone, bioavailable testosterone, and free androgen index were examined as log-transformed continuous variables.

RESULTS

Phthalate metabolites were not statistically significantly associated with sex hormone concentrations among all men. However, associations varied by age. High molecular weight phthalates were associated with lower total, free, and bioavailable testosterone among men age ≥60. Specifically, each doubling of ΣDEHP was associated with 7.72% lower total testosterone among older men (95% confidence interval, -12.76% to -2.39%). Low molecular phthalates were associated with lower total, free, and bioavailable testosterone among men age 20 to 39 and ∑DINCH was associated with lower total testosterone among men age ≥40.

CONCLUSIONS

Our results indicate that males may be vulnerable to different phthalate metabolites in age-specific ways. These results support further investigation into the endocrine-disrupting effects of phthalates.

Endocrine Disruptors in Water and Their Effects on the Reproductive System

Anthropogenic contaminants in water can impose risks to reproductive health. Most of these compounds are known to be endocrine disrupting chemicals (EDCs). EDCs can impact the endocrine system and subsequently impair the development and fertility of non-human animals and humans. The source of chemical contamination in water is diverse, originating from byproducts formed during water disinfection processes, release from industry and livestock activity, or therapeutic drugs released into sewage. This review discusses the occurrence of EDCs in water such as disinfection byproducts, fluorinated compounds, bisphenol A, phthalates, pesticides, and estrogens, and it outlines their adverse reproductive effects in non-human animals and humans.

Subchronic Exposure to Di(2-ethylhexyl) Phthalate and Diisononyl Phthalate During Adulthood Has Immediate and Long-Term Reproductive Consequences in Female Mice

Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer used in a variety of consumer products. This is concerning because DEHP is an endocrine disruptor and ovarian toxicant. Diisononyl phthalate (DiNP) is a DEHP replacement that is a rising human toxicant due to its increased use as a DEHP substitute. However, little is known about the effects of DEHP or DiNP exposure during adulthood on female reproduction. Thus, this study tested the hypothesis that DEHP or DiNP exposure during adulthood has long-term consequences for female reproduction in mice. Adult female CD-1 mice (39-40 days) were orally dosed with vehicle control (corn oil), DEHP (20 µg/kg/day-200 mg/kg/day), or DiNP (20 µg/kg/day-200 mg/kg/day) for 10 days. Females were paired with untreated male mice for breeding trials immediately post-dosing and again at 3 and 9 months post-dosing. Immediately post-dosing, DEHP and DiNP did not affect fertility. At 3 months post-dosing, DiNP (20 and 100 µg/kg/day and 200 mg/kg/day) significantly disrupted estrous cyclicity, and DiNP and DEHP (20 µg/kg/day) significantly reduced the ability of females to get pregnant. At 9 months post-dosing, DiNP significantly disrupted estrous cyclicity (100 µg/kg/day), reduced time to mating (100 µg/kg/day-200 mg/kg/day), and borderline reduced percent of females who produced offspring (20 mg/kg/day). At 9 months post-dosing, DEHP (200 µg/kg/day and 200 mg/kg/day) and DiNP (100 µg/kg/day and 20 and 200 mg/kg/day) increased numbers of male-biased litters. These data show that DEHP and DiNP exposure has long-term consequences for female reproduction, even long after cessation of exposure.

In utero exposure to endocrine-disrupting chemicals and telomere length at birth

Telomere length correlates with morbidity and mortality. While telomere length appears to be influenced by hormone levels, the potential impact of exposure to endocrine-disrupting chemicals (EDCs) has not been studied. We examined the association between maternal gestational concentrations of biomarkers of EDC exposure and telomere length at birth in the Harvard Epigenetic Birth Cohort. EDC (phenols and phthalates) biomarker concentrations were measured in maternal spot urine samples during the first trimester and telomere length in maternal and cord blood collected at delivery among 181 mother-newborn singleton dyads. Maternal and newborn telomere length exhibited a positive correlation (Spearman ρ = 0.20 (p-value< 0.01). Infant telomere length was associated with maternal biomarker concentrations of specific EDCs, and most of these associations were observed to be infant sex-specific. Prenatal exposure to triclosan, a non-paraben phenol with antimicrobial properties, was one of the most strongly associated EDCs with telomere length; telomere length was 20% (95% CI 5%-33%) shorter among boys in the highest quartile of maternal biomarker concentrations compared to the lowest quartile. In contrast, we observed longer telomere length associated with increased gestational concentrations of mono-isobutyl phthalate, and among boys, with increased concentrations of mono-2-ethylhexyl phthalate. In this birth cohort, we observed associations between maternal gestational exposure to select EDC biomarkers and telomere length, most of which were sex-specific. These findings need to be confirmed in future studies.

Update of the risk assessment of di-butylphthalate (DBP), butyl-benzyl-phthalate (BBP), bis(2-ethylhexyl)phthalate (DEHP), di-isononylphthalate (DINP) and di-isodecylphthalate (DIDP) for use in food contact materials

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP Panel) was asked by the European Commission to update its 2005 risk assessments of di‐butylphthalate (DBP), butyl‐benzyl‐phthalate (BBP), bis(2‐ethylhexyl)phthalate (DEHP), di‐isononylphthalate (DINP) and di‐isodecylphthalate (DIDP), which are authorised for use in plastic food contact material (FCM). Dietary exposure estimates (mean and high (P95)) were obtained by combining literature occurrence data with consumption data from the EFSA Comprehensive Database. The highest exposure was found for DINP, ranging from 0.2 to 4.3 and from 0.4 to 7.0 μg/kg body weight (bw) per day for mean and high consumers, respectively. There was not enough information to draw conclusions on how much migration from plastic FCM contributes to dietary exposure to phthalates. The review of the toxicological data focused mainly on reproductive effects. The CEP Panel derived the same critical effects and individual tolerable daily intakes (TDIs) (mg/kg bw per day) as in 2005 for all the phthalates, i.e. reproductive effects for DBP (0.01), BBP (0.5), DEHP (0.05), and liver effects for DINP and DIDP (0.15 each). Based on a plausible common mechanism (i.e. reduction in fetal testosterone) underlying the reproductive effects of DEHP, DBP and BBP, the Panel considered it appropriate to establish a group‐TDI for these phthalates, taking DEHP as index compound as a basis for introducing relative potency factors. The Panel noted that DINP also affected fetal testosterone levels at doses around threefold higher than liver effects and therefore considered it conservative to include it within the group‐TDI which was established to be 50 μg/kg bw per day, expressed as DEHP equivalents. The aggregated dietary exposure for DBP, BBP, DEHP and DINP was estimated to be 0.9–7.2 and 1.6–11.7 μg/kg bw per day for mean and high consumers, respectively, thus contributing up to 23% of the group‐TDI in the worst‐case scenario. For DIDP, not included in the group‐TDI, dietary exposure was estimated to be always below 0.1 μg/kg bw per day and therefore far below the TDI of 150 μg/kg bw per day. This assessment covers European consumers of any age, including the most sensitive groups. Based on the limited scope of the mandate and the uncertainties identified, the Panel considered that the current assessment of the five phthalates, individually and collectively, should be on a temporary basis.

This publication is linked to the following EFSA Supporting Publications article: http://onlinelibrary.wiley.com/doi/10.2903/sp.efsa.2019.EN-1747/full