Phthalate exposure in girls during early puberty

Influence of exposure to endocrine disruptors and other environmental chemicals on breast development in girls: A systematic review of human studies

BACKGROUND

Age at thelarche has decreased over recent decades. This change in female puberty timing may be influenced by exposure to endocrine disrupting chemicals (EDCs) during critical periods of development.

OBJECTIVE

To review the scientific literature for evidence on the association of exposure to EDCs and other environmental chemicals with the timing of thelarche in girls.

METHODS

A systematic search for original peer-reviewed articles published up to July 2023 was conducted in three databases (Medline/PubMed, Scopus, and Web of Science), following the PECO strategy and PRISMA guidelines. The quality of evidence and reporting and the risk of bias were evaluated using GRADE, STROBE, and ROBINS-E tools.

RESULTS

Out of 3094 articles retrieved in the search, 67 met the review inclusion criteria. Data from 10 out of the 14 studies offering high-quality suggest that in utero and/or childhood exposure to certain synthetic and natural chemicals is associated with earlier breast development in girls; 8 of these 10 studies described a relationship with exposure to organohalogenated compounds in utero and to phthalates in childhood.

CONCLUSIONS

This systematic review provides the first overview of available human data on the association of EDCs/environmental chemicals with the timing of thelarche. Further high-quality research is urgently needed to fully elucidate the influence of this exposure on breast development timing in girls.

The relationship between bisphenol A and phthalates with precocious puberty in Vietnamese children

OBJECTIVES

This study is aimed to explore the correlation between bisphenol A (BPA) and phthalates, including diethylhexylphthalate (DEHP) and dibutylphthalate (DBP), and precocious puberty (PP).

METHODS

A case-control study was conducted in Ho Chi Minh City, Vietnam, from November 2021 to April 2022, involving 250 children, with 124 of them diagnosed with PP and 126 serving as controls. We assessed the levels of urinary BPA, DEHP, and DBP in all participants and examined their association with the risk of PP.

RESULTS

BPA was detected in 11.3 % of PP cases but was not found in any individuals in the control group (p<0.001). Diethylhexylphthalate metabolite (MEHP) was not detected in any of the samples. Positive urinary results for dibutylphthalate metabolite (MBP) were observed in 8.1 % of PP cases and 2.4 % in the control group, with an odds ratio of 3.6 (95 % confidence interval: 0.97-13.4, p=0.03).

CONCLUSIONS

The PP group exhibited a higher prevalence of positive urinary BPA and DBP levels compared to the control group.

Association between BMI and age at menarche or spermarche among both sexes: Findings from six successive national surveys in China

Background

To explore trends of the association between body mass index (BMI) and age at menarche or spermarche and its urban-rural disparities from 1995 to 2019.

Methods

A total of 912 753 children and adolescents - including 519 940 9-18 years old girls and 392 813 11-18 years old boys - were involved in six successive cross-sectional surveys conducted across 30 provinces in China from 1995 to 2019. Data on menarche and spermarche was collected using the status quo method, where same-gender physicians conducted face-to-face interviews to determine if children and adolescents had experienced their first menstrual cycle or ejaculation (yes/no). The median age at menarche or spermarche was estimated by probit analysis. Anthropometric measurements measured the height and weight of the study subjects. Children and adolescents were classified into thinness, normal range of weight, overweight, and obesity. t test was used to compare the differences in BMI between premenarchal and postmenarchal girls or prespermarcheal and postspermarcheal boys. Logistic regression was used to explore the associations between BMI/nutritional status and menarche or spermarche stratified by urban or rural residency status.

Results

From 1995 to 2019, BMI in all age groups growth over time, and the values of BMI among children and adolescents under 15 who had menarche or spermarche were more significant than those without menarche or spermarche. In 2019, for girls, thinness was associated with delayed menarche (odds ratio (OR) = 0.26; 95% confidence interval (CI) = 0.24-0.28), while overweight (OR = 1.99; 95% CI = 1.85-2.14) and obesity (OR = 2.20; 95% CI = 1.92-2.53) was associated with advanced menarche. For boys, thinness was associated with delayed spermarche (OR = 0.71; 95% CI = 0.65-0.78), overweight was associated with advanced spermarche (OR = 1.08; 95% CI = 1.01-1.15) while obesity had no association with spermarche. The OR between BMI and menarche in 1995 was 1.35 (95% CI = 1.33-1.37), which decreased to 1.19 (95% CI = 1.18-1.20) by 2019. The OR between BMI and spermarche in 1995 was 1.10 (95% CI = 1.09-1.11), which decreased to 1.02 (95% CI = 1.02-1.03) by 2019. The trends by urban-rural stratification were consistent with the total sample.

Conclusions

We have established a dose-response relationship between BMI and menarche in girls, whereas the association appears to be nonlinear in boys, and the associations were diminishing. Similar findings were observed in both urban and rural areas. Considering the dual adverse effects of obesity and early puberty on health, the results of this study suggest that sexual health education should be strengthened, especially among obese girls. Further research on the influencing factors and biological mechanisms of early puberty will be beneficial.

Phthalates and their effects on human health: Focus on erythrocytes and the reproductive system

Plastics, long-chain artificial polymers, are used worldwide with a global production of 350 million tonnes per year. Various degradation processes transform plastics into smaller fragments divided into micro, meso and macroplastics. In various industries, such as construction, certain plastic additives are used to improve flexibility and enhance performance. Plastic additives include phthalates (PAE), dibutyl phthalate (DPB) and diethyl phthalate (DEP). Due to the use of plastics and plastic additives, these small fragments of different shapes and colours are present in all environmental compartments. For their characteristics, PAEs can be introduced particularly by ingestion, inhalation and dermal absorption. They can accumulate in the human body, where they have already been identified in blood, amniotic fluid and urine. The purpose of this review is to gather the effects that these plastic additives have on various systems in the human body. Being endocrine disruptors, the effects they have on erythrocytes and how they can be considered targets for xenobiotics have been analysed. The influence on the reproductive system was also examined. Phthalates are therefore often overused. Due to their properties, they can reach human tissues and have a negative impact on health. The aim of this review is to give an overview of the presence of phthalates and their hazards. Therefore, the use of these plastic additives should be reduced, replaced and their disposal improved.

A Study of the Relationship between Phthalate Exposure and the Occurrence of Adult Asthma in Taiwan

Although phthalate esters contribute to airway remodeling by increasing bronchial cells' migration and proliferation, the relationship between human exposure to phthalates and asthma is not understood. We measured phthalate exposure in the human body and evaluated its effect on asthma. Asthma (n = 123) and asthma-free (n = 139) participants were, respectively, recruited from an asthma clinic and the community in Taiwan. The urine levels of six phthalate metabolites were determined by liquid chromatography tandem mass spectrometry. Compared with the controls, male asthma patients had higher means of mono-(2-ethylhexyl) phthalate (MEHP) (116.3 nmol/g), monobutyl phthalate (MBP) (850.3 nmol/g) and monoethyl phthalate (MEP) (965.8 nmol/g), and female patients had greater MBP (2902.4 nmol/g). Each 10-fold increase in the level of these phthalate metabolites was correspondingly associated with a 5.0-, 5.8-, 4.2- and 5.3-fold risk of contracting asthma. Male asthma patients were identified to have a higher proportion of MEHP exposure (32.5%) than the controls (25.3%). In asthma patients, an increase in urine MEHP levels and the total phthalate metabolite concentration were notably linked to increased risks of emergency room visits and being hospitalized. For the occurrence and acute clinical events of adult asthma, phthalate exposures and MEHP retention may contribute to higher risks of contracting this respiratory disorder.

Chemical Effects on Breast Development, Function, and Cancer Risk: Existing Knowledge and New Opportunities

Population studies show worrisome trends towards earlier breast development, difficulty in breastfeeding, and increasing rates of breast cancer in young women. Multiple epidemiological studies have linked these outcomes with chemical exposures, and experimental studies have shown that many of these chemicals generate similar effects in rodents, often by disrupting hormonal regulation. These endocrine-disrupting chemicals (EDCs) can alter the progression of mammary gland (MG) development, impair the ability to nourish offspring via lactation, increase mammary tissue density, and increase the propensity to develop cancer. However, current toxicological approaches to measuring the effects of chemical exposures on the MG are often inadequate to detect these effects, impairing our ability to identify exposures harmful to the breast and limiting opportunities for prevention. This paper describes key adverse outcomes for the MG, including impaired lactation, altered pubertal development, altered morphology (such as increased mammographic density), and cancer. It also summarizes evidence from humans and rodent models for exposures associated with these effects. We also review current toxicological practices for evaluating MG effects, highlight limitations of current methods, summarize debates related to how effects are interpreted in risk assessment, and make recommendations to strengthen assessment approaches. Increasing the rigor of MG assessment would improve our ability to identify chemicals of concern, regulate those chemicals based on their effects, and prevent exposures and associated adverse health effects.

A preliminary study on the relationship between environmental endocrine disruptors and precocious puberty in girls

OBJECTIVES

To explore the associations of environmental endocrine disruptors on precocious puberty in girls.

METHODS

This was a case-control study in which 30 girls with precocious puberty and 46 age- and race-matched prepubertal females were enrolled. The concentrations of 10 environment endocrine disruptors (bisphenol A, bisphenol B, butylparaben, propylparaben, ethvlparaben, methylparaben, mono-butyl phthalate, mono-2-ethylhexyl phthalate, monoethyl phthalate, and monomethyl phthalate) in urine and 10 steroid hormones (dihydrotestosterone, corticosterone, hydrocortisone, 11-deoxycortisol, 17α-hydroxy progesterone, 4-androstene-3,17-dione, estrone, deoxycorticosterone, pregnenolone, and dehydroepiandrosterone) in serum were detected with the liquid chromatography-mass spectrometry (LC-MS).

RESULTS

According to the Mann-Whitney U test, urinary levels of bisphenol A, monobutyl phthalate, and monomethyl phthalate were significantly higher in the precocious group than in the prepubertal group, and blood levels of hydrocortisone, 11-deoxycortisol, corticosterone, deoxycorticosterone, and pregnenolone were significantly lower in the precocious group than in the prepubertal group (p<0.05, VIP>1).

CONCLUSIONS

Our findings confirm the association between phthalate exposure and the incidence of precocious puberty in girls. Control and reduction of children exposure to phthalate esters should be considered as a health priority.

Monitoring Phthalates in Maternal and Cord Blood: Implications for Prenatal Exposure and Birth Outcomes

Although many phthalates are endocrine-disrupting chemicals that are associated with adverse birth outcomes, the relationship between maternal phthalate exposure and birth outcomes is not yet conclusive. The objective of the present study was to investigate the association between prenatal exposure to phthalates in human maternal and cord blood and birth outcomes of the infants. Sixty-five mother-infant pairs were recruited in Taipei City and New Taipei City, and birth outcomes of the infants were recorded. Twelve phthalate metabolites were measured in maternal and cord blood samples. The mean of mono-ethyl phthalate, mono-isobutyl phthalate (MiBP), mono-n-butyl phthalate (MnBP), and mono-(2-ethylhexyl) phthalate (MEHP) was relatively higher than that of the other metabolites in both maternal and infant blood. There was a significant difference (p < 0.05) for mono-methyl phthalate (MMP) and MnBP between the maternal blood and cord blood of male infants. Mono-benzyl phthalate (MBzP), MMP, MiBP, and ∑di-2-ethylhexyl phthalate (∑DEHP) in maternal blood were inversely correlated with the anogenital index (AGI) of male infants, with a p value between 0.011 and 0.033. Mono-n-octyl phthalate, MMP, MiBP, MnBP, and MBzP were positively correlated with the AGI of female infants, with a p value between 0.001 and 0.034. Cord blood levels of MnBP, mono-(2-ethyl-5-oxohexyl)-phthalate, MEHP, and ∑DEHP were found to be inversely associated with head circumference in all the infants, adjusted for gestational age. Phthalate monoesters are potentially estrogenic and antiandrogenic chemicals. Longitudinal follow-up of the present study population could help clarify the long-term impact of phthalates on growth and the health effects of background exposure levels. Environ Toxicol Chem 2022;41:715-725. © 2022 SETAC.

Update about the disrupting-effects of phthalates on the human reproductive system

Phthalate esters are synthetic chemicals used in the plastic industry as plasticizers and consumable products. According to United Nations, about 400 million tons of plastic are produced every year. In parallel with increased production, the concerns about its effects on human health have increased because phthalates are endocrine-disrupting compounds. Humans are continuously exposed to phthalates through different routes of exposure. Experimental data have associated the phthalates exposure to adverse effects on development and reproduction in women (e.g., earlier puberty, primary ovarian insufficiency, endometriosis, preterm birth, or in vitro fertilization) and men (e.g., anogenital distance, cryptorchidism, hypospadias, and changes in adult reproductive function) although there is no consensus. Therefore, one question arises: could the increase in infertility be related to phthalates exposure? To answer this question, we aimed to assess the disrupting-effects of phthalates on the human reproductive system. For this, we reviewed the current literature based on epidemiological and experimental data and experimental studies in humans. The phthalate effects were discussed in a separate mode for female and male reproductive systems. In summary, phthalates induce toxicity in the reproductive system and human development. The increased plastic production may be related to the increase in human infertility.

Xenoestrogen exposure and kidney function in the general population: Results of a community-based study by laboratory tests and questionnaire-based interviewing

BACKGROUND

Chronic kidney disease (CKD) is a growing concern worldwide. Exposure to xenoestrogens (XEs), such as phthalates, parabens, and phenols, lead to CKD. However, kidney function and its complex relationship with XEs, lifestyle, and dietary habits are not well understood.

METHODS

In the present cross-sectional community-based cohort study, we enrolled 887 subjects for a questionnaire-based interview and laboratory tests. XE exposure concerning lifestyle/dietary habits were evaluated using questionnaires. Urinary levels of 17XE metabolites were measured in 60 subjects with high exposure risk scores and 60 subjects with low exposure risk scores.

RESULTS

Univariate and multivariate linear regression showed that a high exposure score (β ± SE: 4.226 ± 1.830, P = 0.021) was independently negatively associated with eGFR in 887 subjects. Univariate and multivariate linear regression to urinary XEs and urine albumin creatinine excretion ratio (UACR) in 120 subjects indicated that ethylparaben (EP) (β: 1.934, 95% CI: 0.135-3.733, P = 0.035) was significantly associated with increased UACR. Multivariate regression analyses of the CKD subgroup (n = 38), after adjusting for age, showed that higher levels of mono-(2-ethylhexyl) phthalate (MEHP), EP, nonylphenol (NP), and benzophenone-3 (BP-3) were significantly associated with lower estimated glomerular filtration rate (eGFR). Higher urinary levels of MEHP (OR: 3.037, 95% CI: 1.274-7.241) were more likely associated with high exposure scores (>5 points), after adjusting for diabetes, gender, eGFR, age, Na, Ca, albumin, vitamin D, systolic blood pressure (SBP), white blood cell count, total bilirubin, aspartate transaminase, and heart rate. MEHP (β ± SE: 0.033 ± 0.009, P < 0.001) was also significantly positively associated with total exposure scores after applying multivariate linear regression analyses.

CONCLUSION

XE exposure scores obtained from the questionnaires were negatively associated with kidney function. Urinary metabolites of XEs, including EP, NP, BP-3, and MEHP, are potential risk factors for microalbuminuria and decline in kidney function. MEHP seemed to have the strongest correlation with high exposure scores and decline in kidney function.

Precocious puberty in Korean girls with and without exposure to endocrine-disrupting chemicals in toy slime: a comparative analysis

BACKGROUND

Toy slime is popular in Korea, and in parallel, pre-pubertal girls visit hospitals for early pubertal signs. Thus far, numerous studies have investigated the association of endocrine-disrupting chemicals (EDCs) with precocious puberty (PP). However, there is a lack of studies on the clinical manifestations and sex hormones. We aimed to investigate early pubertal development in Korean girls with or without a history of toy slime exposure and determine changes in bone age, Tanner stage, and sex hormones.

METHODS

In this study, 140 girls underwent stimulation tests at Kyungpook National University Children's Hospital Endocrinology Department, during January 2018 and December 2020. Patients were divided into two groups for gonadotropin-releasing hormone (GnRH) stimulation test and frequency of exposure to toy slime (EDCs). GnRH stimulation test was conducted after an intravenous injection of 100 µg of luteinizing hormone-releasing hormone. Slime exposure was defined as Slime ≥ 3 times/week for ≥ 3 months.

RESULTS

History of slime exposure was found in 14 of 58 and 65 of 82 patients in the central PP (CPP) and non-CPP groups, respectively. Slime-exposed patients had advanced bone age, although their Tanner stage was low. Patients with a history of toy slime exposure were 5.5 times more likely to be diagnosed with non-CPP than patients without slime exposure (p < 0.05).

CONCLUSIONS

Exposure to toy slime in prepubertal girls may be associated with rapid clinical advancement of pubertal development and bone age, and the patients appear more likely to be diagnosed with non-CPP.

The effects of phthalate ester exposure on human health: A review

Phthalate esters (PAEs) are one of the most widely used plasticizers in polymer products and humans are increasingly exposed to them. The constant exposure to PAEs-contained products has raised some concerns against human health. Thus, the impacts of PAEs and their metabolites on human health require a comprehensive study for a better understanding of the associated risks. Here, we attempt to review eight main health effects of PAE exposure according to the most up-to-date studies. We found that epidemiological studies demonstrated a consistent association between PAE exposure (especially DEHP and its metabolites) and a decrease in sperm quality in males and symptom development of ADHD in children. Overall, we found insufficient evidence and lack of consistency of the association between PAE exposure and cardiovascular diseases (hypertension, atherosclerosis, and CHD), thyroid diseases, respiratory diseases, diabetes, obesity, kidney diseases, intelligence performance in children, and other reproductive system-related diseases (anogenital distance, girl precocious puberty, and endometriosis). Future studies (longitudinal and follow-up investigations) need to thoroughly perform in large-scale populations to yield more consistent and powerful results and increase the precision of the association as well as enhance the overall understanding of potential human health risks of PAEs in long-term exposure.

Phthalate Exposure Pattern in Breast Milk within a Six-Month Postpartum Time in Southern Taiwan

Di-(2-ethylhexyl) phthalate (DEHP), a common plasticizer, has been detected in breast milk in many countries; however, whether phthalate metabolite concentration and the detection rate in breast milk change postpartum is still unknown. We measured phthalate metabolite concentrations in breast milk in the first 6 months postpartum in women enrolled in the E-Da hospital from January to July 2017. A total of 56 breastfeeding mothers and 66 samples were included in this study. We analyzed the samples’ concentration of eight phthalate metabolites using liquid chromatography mass spectrometry. The concentration of mono-2-ethylhexyl phthalate (MEHP) was significantly higher in the first month, and then decreased over time. The detection rate of ono-isobutyl phthalate (MiBP) and mono-n-butyl phthalate (MBP) was low in the first month and then increased over time. Compared with a previous study published in 2011, the levels of MEHP and MiBP in breast milk were much lower in the present study, suggesting an increased awareness of the health risks of phthalate exposure after a food scandal occurred in Taiwan. This study provides information for evaluating newborns’ exposure to different kinds of phthalate through human milk in the postpartum period.

Phthalates and Their Impacts on Human Health

Phthalates are a series of widely used chemicals that demonstrate to be endocrine disruptors and are detrimental to human health. Phthalates can be found in most products that have contact with plastics during producing, packaging, or delivering. Despite the short half-lives in tissues, chronic exposure to phthalates will adversely influence the endocrine system and functioning of multiple organs, which has negative long-term impacts on the success of pregnancy, child growth and development, and reproductive systems in both young children and adolescents. Several countries have established restrictions and regulations on some types of phthalates; however, we think that more countries should establish constraints or substitute measures for phthalates to reduce health risks. This article aims to summarize the adverse impacts of phthalates on human health, analyze the toxicity mechanism, assess the risks, and finally provide feasible strategies to reduce exposure of the public to phthalates.

Reproductive toxic potential of phthalate compounds - State of art review

Phthalates are pervasive compounds, and due to the ubiquitous usage of phthalates, humans or even children are widely exposed to them. Since phthalates are not chemically bound to the plastic matrix, they can easily leach out to contaminate the peripheral environment. Various animal and human studies have raised vital health concern including developmental and reproductive toxicity of phthalate exposure. The present review is based upon the available literature on phthalates with respect to their reproductive toxic potential. Common reproductive effects such as declined fertility, reduced testis weight, variations in accessory sex organs and several female reproductive disorders appeared to be largely associated with the transitional phthalates. Among the higher molecular weight phthalates (≥ C7), di-isononyl phthalate (DINP) produces some minor effects on development of male reproductive tract and among low molecular weight phthalates (≤C3), di-methyl (DMP) and di-isobutyl (DIBP) phthalate produce some adverse effects on male reproductive system. Whereas transitional phthalates such as di-butyl phthalate, benzyl butyl phthalate, and di-(2-ethylhexyl) phthalate have shown adverse effects on female reproductive system. Owing to these, non-toxic alternatives to phthalates may be developed and use of phthalates could be rationalized as an important issue where human reproduction system is involved. Though, more epidemiological studies are needed to substantiate the reported findings on phthalates.

Effects of Phthalate Esters on Human Myometrial and Fibroid Cells: Cell Culture and NOD-SCID Mouse Data

Evidence is growing that phthalate esters play an important role in the pathogenesis of estrogen-dependent gynecologic diseases, especially uterine fibroids. We aimed to investigate whether in vitro treatment with di-(2-ethylhexyl)-phthalate (DEHP) affects angiogenesis, proliferation, and apoptosis in uterine fibroids. To ascertain this, we evaluated vascular endothelial growth factor (VEGF) expression and AKT/ERT phosphorylation and compared the fibroid volume between nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice fed with and without DEHP. VEGF expression was measured using enzyme-linked immunosorbent assay, and AKT/ERK phosphorylation was analyzed by western blot analysis in human myometrial and fibroid cells. The volume of the fibroid tissues implanted to NOD/SCID mice was measured, and the expression of collagen type I protein, Ki-67, proliferating cell nuclear antigen, and B cell lymphoma 2 were analyzed using immunohistochemistry. We could see significant increases in VEGF expression and AKT phosphorylation in human myometrial and fibroid cells treated with DEHP. The volume of the fibroid tissues was significantly increased in NOD/SCID mice fed with DEHP, which was accompanied by increased expression of collagen type I and AKT phosphorylation. Taken together, these results suggest that exposure to phthalate esters may influence uterine fibroid pathogenesis by increasing VEGF and collagen expression and upregulating AKT phosphorylation.

A Complex Systems Model of Breast Cancer Etiology: The Paradigm II Conceptual Model

BACKGROUND

The etiology of breast cancer is a complex system of interacting factors from multiple domains. New knowledge about breast cancer etiology continues to be produced by the research community, and the communication of this knowledge to other researchers, practitioners, decision makers, and the public is a challenge.

METHODS

We updated the previously published Paradigm model (PMID: 25017248) to create a framework that describes breast cancer etiology in four overlapping domains of biologic, behavioral, environmental, and social determinants. This new Paradigm II conceptual model was part of a larger modeling effort that included input from multiple experts in fields from genetics to sociology, taking a team and transdisciplinary approach to the common problem of describing breast cancer etiology for the population of California women in 2010. Recent literature was reviewed with an emphasis on systematic reviews when available and larger epidemiologic studies when they were not. Environmental chemicals with strong animal data on etiology were also included.

RESULTS

The resulting model illustrates factors with their strength of association and the quality of the available data. The published evidence supporting each relationship is made available herein, and also in an online dynamic model that allows for manipulation of individual factors leading to breast cancer (https://cbcrp.org/causes/).

CONCLUSIONS

The Paradigm II model illustrates known etiologic factors in breast cancer, as well as gaps in knowledge and areas where better quality data are needed.

IMPACT

The Paradigm II model can be a stimulus for further research and for better understanding of breast cancer etiology.

Association of phthalate exposure with precocious and delayed pubertal timing in girls and boys: a systematic review and meta-analysis

Exposure to phthalate derivatives has adverse effects on the health and development of humans, especially for children. A growing body of evidence supports the idea that exposure to phthalates can change an individual's physiological set point and the time of puberty in both genders. In this systematic review and meta-analysis, recent studies were evaluated to obtain systematic and regulation results in relation to puberty status and phthalate exposure in girls and boys. We searched English-language papers using Scopus, ISI, and PubMed databases as search engines, with no restriction of time, until the end of July 2019. A comprehensive literature search for an association between phthalate exposure and signs of puberty as well as levels of different types of hormones was carefully performed. Of the 67 studies retained for full-text screening, 39 studies were eligible for data management and extraction. For conducting a meta-analysis, four studies had appropriate effect size and metrics for pooling in the meta-analysis. Our findings revealed that low and high exposure to phthalates could alter pubertal development in both genders; the effects were either early or delayed puberty such as changes in the pubarche, thelarche, and menarche time, as well as in testicular volume. We statistically analyzed the association of pubic-hair development, breast development, and menarche time with exposure to phthalates in girls. For example, the pooled odds ratios of mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono (2-ethyl-5-oxohexyl) phthalate (MEOHP) in relation to breast development were (OR: 1.48, 95% CI: 1.11-1.85) and (OR: 1.52, 95% CI: 1.15-1.58) (P-value < 0.001), respectively. In addition, we analyzed the correlation between pubic-hair development and testicular volume with exposure to phthalates in boys. To the best of our knowledge, this is the first systematic review and meta-analysis of its kind for girls and boys. In conclusion, we found that a positive association exists between phthalate exposure and pubertal timing in the pediatric age group. Therefore, prevention of exposure to phthalates and reduction of their use should be underscored in the strategies for primordial prevention of pubertal timing and related consequences.

Environmental Exposures during Puberty: Window of Breast Cancer Risk and Epigenetic Damage

During puberty, a woman’s breasts are vulnerable to environmental damage (“window of vulnerability”). Early exposure to environmental carcinogens, endocrine disruptors, and unhealthy foods (refined sugar, processed fats, food additives) are hypothesized to promote molecular damage that increases breast cancer risk. However, prospective human studies are difficult to perform and effective interventions to prevent these early exposures are lacking. It is difficult to prevent environmental exposures during puberty. Specifically, young women are repeatedly exposed to media messaging that promotes unhealthy foods. Young women living in disadvantaged neighborhoods experience additional challenges including a lack of access to healthy food and exposure to contaminated air, water, and soil. The purpose of this review is to gather information on potential exposures during puberty. In future directions, this information will be used to help elementary/middle-school girls to identify and quantitate environmental exposures and develop cost-effective strategies to reduce exposures.

PM2.5 bound phthalates in four metropolitan cities of China: Concentration, seasonal pattern and health risk via inhalation

Phthalates (PAEs) are in a group of artificial chemicals with potential adverse effects to human health and they can be frequently detected in environmental matrices due to its extensive usage. However, seasonal patterns of concentrations in atmosphere and risks posed by PAEs in airborne PM_2.5 to Chinese population have not been well characterized. During the period of November 2015 to March 2017, samples of fine particulate matter (PM_2.5) were collected in four cities of Guangzhou, Shanghai, Beijing and Harbin, which are major metropolitan areas of various latitudes of China. Concentrations of fourteen PAEs in airborne PM_2.5 were quantified using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS). Estimated daily intakes (EDIs), hazard quotients (HQs) and hazard index (HI) were calculated. Lifetime average daily doses (LADD) and incremental lifetime cancer risks (ILCR) of di(2-ethylhexyl) phthalate (DEHP) for four age groups, which divide with infant, toddler, adolescent and adult, by inhalation route were evaluated. Dimethyl phthalate (DMP), Diethyl phthalate (DEP), Di-n-butyl phthalate (DBP), and DEHP were the four major PAEs contaminants in these PM_2.5 samples. The sum concentrations of DMP, DEP, DBP and DEHP in Guangzhou, Shanghai, Beijing and Harbin ranged from 32.5-76.1, 10.1-101, 8.02-107 and 13.5-622 ng/m³, with mean concentrations of 59.1, 50.8, 43.8 and 136 ng/m³, respectively. The concentration of total PAEs in PM_2.5 from higher latitudes city (Harbin) was higher than those from lower latitudes cities (Guangzhou and Shanghai). Total concentrations of PAEs were significantly higher during warmer seasons than those during colder seasons among the four cities. Although the EDIs, HQs, and HI for all age groups were less than the threshold set by the U.S. Environmental Protection Agency (US EPA) and European Food Safety Authority (EFSA), the highest values of 70-years ILCR from Shanghai and Harbin were 1.2 × 10^-6 and 1.3 × 10^-6, which were slightly beyond the acceptable level of 10^-6. These findings reveal that the cancer risks of DEHP bound to PM_2.5 in these two cites should be of particular concern.

The analysis of endocrine disruptors in patients with central precocious puberty

Background

A few studies have reported a positive association between phthalate exposure and pubertal timing, but several conflicting reports exist. The main objective of the study was to determine whether phthalate exposure was associated with central precocious puberty in girls.

Methods

This was a multicenter case-control study wherein 47 girls with central precocious puberty (CPP) and 47 controls (26 pre-pubertal girls and 21 pubertal girls) were enrolled. No obese girls were included. Five phthalate metabolites (creatinine adjusted) and bisphenol A (BPA) were measured in the first spot urine samples of these 94 girls in the early morning.

Results

The median values of monobenzyl phthalate (MBzP), mono-2-ethyl-5-carboxypentyl phthalate (MECPP), mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP), mono-2-ethyl-5-oxohexyl phthalate (MEOHP), and mono-n-butyl phthalate (MnBP) were 3.1, 29.3, 18.0, 15.4, and 25.2 μg/g creatinine in the CPP group, 4.3, 53.7, 35.7, 29.1, and 66.0 μg/g creatinine in the pre-pubertal control group, and 1.7, 28.7, 21.4, 12.1, and 33.3 μg/g creatinine in the pubertal control group, respectively.

The urinary concentration of the five phthalates was significantly lower in the CPP group than in the pre-pubertal control group (P < 0.001). Conversely, there was no significant difference in the urinary concentration of the five phthalates between the CPP and pubertal control groups (P values: 0.077 for MBzP, 0.733 for MECPP, 0.762 for MEHHP, 0.405 for MEOHP, and 0.981 for MnBP). In addition, the BPA level was not significantly different between the CPP and pubertal control groups (BPA median values: 0.63 μg/g creatinine, the CPP group; 1.7 μg/g creatinine, the pubertal control group; P value = 0.092).

Conclusions

Our study showed that there was no significant difference in the urinary phthalate levels between the CPP and pubertal control groups. Moreover, phthalate metabolites were significantly lower in the CPP group than in the pre-pubertal control group. Further investigation about endocrine disruptors and pubertal progression is needed.

Phthalate exposure and female reproductive and developmental outcomes: a systematic review of the human epidemiological evidence

OBJECTIVE

We performed a systematic review of the epidemiology literature to identify the female reproductive and developmental effects associated with phthalate exposure.

DATA SOURCES AND STUDY ELIGIBILITY CRITERIA

Six phthalates were included in the review: di(2-ethylhexyl) phthalate (DEHP), diisononyl phthalate (DINP), dibutyl phthalate (DBP), diisobutyl phthalate (DIBP), butyl benzyl phthalate (BBP), and diethyl phthalate (DEP). The initial literature search (of PubMed, Web of Science, and Toxline) included all studies of female reproductive and developmental effects in humans, and outcomes were selected for full systematic review based on data availability.

STUDY EVALUATION AND SYNTHESIS METHODS

For each outcome, studies were evaluated using criteria defined a priori for risk of bias and sensitivity by two reviewers using a domain-based approach. Evidence was synthesized by outcome and phthalate and strength of evidence was summarized using a structured framework.

RESULTS

The primary outcomes reviewed here are (number of included/excluded studies in parentheses): pubertal development (5/13), time to pregnancy (3/4), preterm birth (8/12), and spontaneous abortion (5/0). Among these outcomes, preterm birth had moderate evidence of a positive association with phthalate exposure (specifically DEHP, DBP, and DEP). Exposure levels for BBP, DIBP, and DINP were generally lower than for the phthalates with an observed effect, which may partially explain the difference due to lower sensitivity. Other phthalate/outcome combinations were considered to have slight or indeterminate evidence of an association.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

Overall, these results support that some phthalates may be associated with higher odds of preterm birth in humans, though there is some remaining inconsistency. More evidence is needed on the mechanism and relevant exposure window for this association. The views expressed are those of the authors and do not necessarily represent the views or policies of the U.S. EPA.

A strategy to validate a selection of human effect biomarkers using adverse outcome pathways: Proof of concept for phthalates and reproductive effects

Human biomonitoring measures the concentrations of environmental chemicals or their metabolites in body fluids or tissues. Complementing exposure biomarkers with mechanistically based effect biomarkers may further elucidate causal pathways between chemical exposure and adverse health outcomes. We combined information on effect biomarkers previously implemented in human observational studies with mechanisms of action reported in experimental studies and with information from published Adverse Outcome Pathways (AOPs), focusing on adverse reproductive effects of phthalate exposure. Phthalates constitute a group of chemicals that are ubiquitous in consumer products and have been related to a wide range of adverse health effects. As a result of a comprehensive literature search, we present an overview of effect biomarkers for reproductive toxicity that are substantiated by mechanistic information. The activation of several receptors, such as PPARα, PPARγ, and GR, may initiate events leading to impaired male and female fertility as well as other adverse effects of phthalate exposure. Therefore, these receptors appear as promising targets for the development of novel effect biomarkers. The proposed strategy connects the fields of epidemiology and toxicology and may strengthen the weight of evidence in observational studies that link chemical exposures to health outcomes.

Early-life exposure to endocrine-disrupting chemicals and pubertal development in girls

Over the last decades, the onset of puberty in girls has occurred earlier, but the tempo of pubertal progression has been relatively slower, resulting in a younger age at puberty onset without a change in age at menarche. Sufficient energy availability and adiposity contribute to early pubertal development, and environmental factors, such as endocrine-disrupting chemicals (EDCs), may affect not only the control of energy balance, but also puberty and reproduction. EDCs are hormonally active substances that can perturb puberty by acting both peripherally on target organs, such as adipose tissue or adrenal glands, and/or centrally on the hypothalamic-pituitary-gonadal (HPG) axis. Depending on whether the exposure takes place earlier during fetal and neonatal life or later during early childhood, EDCs can lead to different outcomes through different mechanisms. Evidence of associations between exposures to EDCs and altered pubertal timing makes it reasonable to support their relationship. However, human epidemiologic data are limited or inconsistent and cannot provide sufficient evidence for a causal relationship between EDC exposure and changes in pubertal timing. Further investigation is warranted to determine the overall or different effects of EDCs exposure during prenatal or childhood windows on pubertal milestones and to reveal the underlying mechanisms, including epigenetic marks, whereby early-life exposure to EDCs affect the HPG-peripheral tissue axis.

Urinary Phthalate Biomarker Concentrations and Postmenopausal Breast Cancer Risk

BACKGROUND

Growing laboratory and animal model evidence supports the potentially carcinogenic effects of some phthalates, chemicals used as plasticizers in a wide variety of consumer products, including cosmetics, medications, and vinyl flooring. However, prospective data on whether phthalates are associated with human breast cancer risk are lacking.

METHODS

We conducted a nested case-control study within the Women's Health Initiative (WHI) prospective cohort (n = 419 invasive case subjects and 838 control subjects). Control subjects were matched 2:1 to case subjects on age, enrollment date, follow-up time, and WHI study group. We quantified 13 phthalate metabolites and creatinine in two or three urine samples per participant over one to three years. Multivariable conditional logistic regression analysis was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for breast cancer risk associated with each phthalate biomarker up to 19 years of follow-up.

RESULTS

Overall, we did not observe statistically significant positive associations between phthalate biomarkers and breast cancer risk in multivariable analyses (eg, 4th vs 1st quartile of diethylhexyl phthalate, OR = 1.03, 95% CI = 0.91 to 1.17). Results were generally similar in analyses restricted to disease subtypes, to nonusers of postmenopausal hormone therapy, stratified by body mass index, or to case subjects diagnosed within three, five, or ten years.

CONCLUSIONS

In the first prospective analysis of phthalates and postmenopausal breast cancer, phthalate biomarker concentrations did not result in an increased risk of developing invasive breast cancer.

Association of Prenatal Urinary Concentrations of Phthalates and Bisphenol A and Pubertal Timing in Boys and Girls

BACKGROUND

Animal studies suggest that phthalates and bisphenol A (BPA), endocrine-disrupting chemicals found in many consumer products, may impact the timing of puberty.

OBJECTIVES

We aimed to determine the association of prenatal exposure to high-molecular-weight phthalates and BPA with pubertal timing in boys and girls participating in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) longitudinal cohort study.

METHODS

We quantified urinary concentrations of eight phthalate metabolites and BPA at two time points during pregnancy among participating mothers ([Formula: see text]) and conducted clinical Tanner staging of puberty on their children every 9 months between 9 and 13 y of age. We conducted accelerated failure time models and examined the role of child overweight/obese status in this association.

RESULTS

The sum of urinary metabolites of di(2-ethylhexyl) phthalate [Formula: see text], monobenzyl phthalate (MBzP), and BPA were associated with later onset of at least one of the three outcomes assessed in girls (thelarche, pubarche, or menarche) and with earlier onset of at least one of the two outcomes assessed in boys (gondarche and pubarche). We found that monocarboxynonyl phthalate, monocarboxyoctyl phthalate, mono(3-carboxypropyl) phthalate, and BPA were associated with later pubarche and menarche mostly among normal-weight girls but not overweight/obese girls. MBzP was associated with later thelarche in all girls, and [Formula: see text] was associated with later thelarche and menarche in all girls. BPA and all phthalate biomarkers were associated with earlier gonadarche and pubarche in all boys as well as in overweight/obese boys when stratified by weight. Among normal-weight boys, associations with BPA were also inverse, whereas associations with phthalate metabolites were close to the null or positive.

CONCLUSIONS

Several high-molecular-weight phthalates and BPA were associated with later puberty in girls and earlier puberty in boys included in the CHAMACOS cohort study. Childhood overweight/obesity may modify these associations. https://doi.org/10.1289/EHP3424.

Is there any association between phthalate exposure and precocious puberty in girls?

Considerable increase in the prevalence of precocious puberty (PP) during the last decade has raised a lot of concerns. Some environmental endocrine disruptor chemicals (EDCs), such as phthalate esters, have intrinsic estrogen activity or increase endogenous sex hormone levels leading to PP. This study was conducted to investigate the association between exposure to phthalate esters and PP in a sample of girls. Plasma levels of seven phthalate ester metabolites were measured in 87 girls with PP and 63 age- and sex-matched controls by dispersive liquid-liquid microextraction and GC/MS analysis. History of exposure to main sources of phthalates was obtained by a checklist. Diethyl hexyl phthalate (DEHP) metabolite levels were significantly higher in those with PP than that in controls (p < 0.05), but this difference was not significant for other phthalate metabolites. 30.1% girls with PP and 12.2% of controls had played for more than 2 h/day with plastic toys in their childhood. 65.1% girls with PP and 32.8% of controls have regularly used some cosmetic products. Consumption of bottled water and beverages by those with PP was about twofold higher than that in the control group. A positive correlation was found between bottled ware consumption and plasma concentrations of four phthalate metabolites. The frequency of seafood consumption was not significantly different between the groups studied. Our findings confirm positive association between phthalate exposure and incidence of PP in girls. Control and reduction of children exposure to phthalate esters should be considered as a health priority.

Childhood and adolescent phenol and phthalate exposure and the age of menarche in Latina girls

BACKGROUND

The age of menarche has been associated with metabolic and cardiovascular disease, as well as cancer risk. The decline in menarcheal age over the past century may be partially attributable to increased exposure to endocrine disrupting chemicals (EDCs).

METHODS

We assessed the influence of 26 phenol and phthalate biomarkers on the timing of menarche in a longitudinal cohort of Chilean girls. These EDCs were quantified in urine collected prior to the onset of breast development (Tanner 1; B1), and during adolescence (Tanner 4; B4). Multivariable accelerated failure time (AFT) models were used to analyze associations between biomarker concentrations and the age of menarche adjusting for body mass index (BMI) Z-score and maternal education, accounting for within-subject correlation.

RESULTS

Several biomarkers were significantly associated with the age at menarche; however, these associations were dependent on the timing of biomarker assessment. A log(ng/ml) increase in B1 concentrations of di(2-ethylhexyl) phthalate biomarkers was associated with later menarche (hazard ratio (HR): 0.77; 95% CI: 0.60, 0.98), whereas higher B1 concentrations of 2,5-dichlorophenol and benzophenone-3 were associated with earlier menarche (HR: 1.13; 95% CI: 1.01, 1.27; HR: 1.17; 95% CI: 1.06, 1.29, respectively). Elevated B4 concentrations of monomethyl phthalate were similarly associated with earlier menarche (HR: 1.30; 95% CI: 1.10, 1.53). The impact of monoethyl phthalate and triclosan concentrations on pubertal timing were significantly modified by BMI Z-score. Higher monoethyl phthalate and triclosan concentrations were associated with earlier menarche among overweight or obese girls, but not among those that were normal weight.

CONCLUSIONS

This study identifies modulation of sexual maturation by specific EDC biomarkers in Latina girls.

State of the evidence 2017: an update on the connection between breast cancer and the environment

BACKGROUND

In this review, we examine the continually expanding and increasingly compelling data linking radiation and various chemicals in our environment to the current high incidence of breast cancer. Singly and in combination, these toxicants may have contributed significantly to the increasing rates of breast cancer observed over the past several decades. Exposures early in development from gestation through adolescence and early adulthood are particularly of concern as they re-shape the program of genetic, epigenetic and physiological processes in the developing mammary system, leading to an increased risk for developing breast cancer. In the 8 years since we last published a comprehensive review of the relevant literature, hundreds of new papers have appeared supporting this link, and in this update, the evidence on this topic is more extensive and of better quality than that previously available.

CONCLUSION

Increasing evidence from epidemiological studies, as well as a better understanding of mechanisms linking toxicants with development of breast cancer, all reinforce the conclusion that exposures to these substances - many of which are found in common, everyday products and byproducts - may lead to increased risk of developing breast cancer. Moving forward, attention to methodological limitations, especially in relevant epidemiological and animal models, will need to be addressed to allow clearer and more direct connections to be evaluated.

The effects of phthalates in the cardiovascular and reproductive systems: A review

Every year millions of tons of plastic are produced around the world and humans are increasingly exposed to them. This constant exposure to plastics has raised some concerns against human health, particularly when it comes to phthalates. These compounds have endocrine-disrupting properties, as they have the ability to bind molecular targets in the body and interfere with hormonal function and quantity. The main use of phthalates is to give flexibility to polyvinyl chloride (PVC) polymers. Phthalates are found in a variety of industrial and consumer products, and as they are not covalently bound to the plastic, phthalates contaminate the environment from which human exposure occurs. Studies in human and animal populations suggest a correlation between phthalate exposure and adverse health outcomes, particularly at the reproductive and cardiovascular systems, however there is much less information about the phthalate toxicity of the later. Thus, the main purpose of this review is to present the studies relating the effects already stated of phthalates on the cardiovascular and reproductive systems, and also present the link between these two systems.

Association of PAEs with Precocious Puberty in Children: A Systematic Review and Meta-Analysis

Background: Precocious puberty (PP) currently affects 1 in 5000 children and is 10 times more common in girls. Existing studies have tried to detect an association between phathalic acid esters (PAEs) and PP, but the results did not reach a consensus. Objective: To estimate the association between PAEs and children with PP based on current evidence. Methods: Databases including PubMed (1978 to March 2015), OVID (1946 to March 2015), Web of Science (1970 to March 2015), EBSCO (1976 to March 2015), CNKI (1979 to March 2015), WANFANG DATA (1987 to March 2015), CBM (1978 to March 2015) and CQVIP (1989 to March 2015) were searched to identify all case-control studies that determined the exposure and concentration of PAEs and their metabolites in children with PP. Meta-analysis of the pooled standard mean difference (SMD) and odds ratio (OR) with 95% confidence intervals (CI) were calculated. Results: A total of 14 studies involving 2223 subjects were finally included. The pooled estimates showed that PP was associated with di-(2-ethylhexyl)-phthalate (DEHP) exposure (OR: 3.90, 95% CI: 2.77 to 5.49). Besides, the concentration of DEHP (SMD: 1.73, 95% CI: 0.54 to 2.91) and di-n-butyl phthalate (DBP) (SMD: 4.31, 95% CI: 2.67 to 5.95) in the PP group were significantly higher than those in the control group, respectively, while no difference was detected between case and control groups in either serum or urinary concentration of mono-(2-ethylhexyl)-phthalate (MEHP), monobutyl phthalate (MBP), mono(2-ethyl-5-oxohexyl) phthalate(MEOHP), mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP), monomethyl phthalate (MMP), monobenzyl phthalate (MBzP) or monoethyl phthalate (MEP). Conclusions: Exposure of DEHP and DBP might be associated with PP risk for girls, however, there is no evidence to show an association between the exposure to most PAE metabolites and PP. Given the moderate strength of the results, well-designed cohort studies with large sample size should be performed in future.

A systematic review on the effects of environmental exposure to some organohalogens and phthalates on early puberty

Background:

Early puberty is a common worldwide problem. Different parameters as genetics, metabolic diseases, obesity, as well as environmental factors may affect the age of puberty. This systematic review aims to survey the related literature on the effects of environmental pollutants and especially organohalogens and phthalates on early puberty.

Materials and Methods:

A systematic review of papers published in the English language was completed in January 2014. Studies on the associations of organohalogens and phthalates with the puberty time were included. A literature search was conducted in EMBASE, PubMed, Scopus, ISI Web of Science, and Cochrane Library from 1995 to January 2014; moreover manual search through references of relevant manuscripts was considered. The literature search identified 212 papers, of which 13 papers fulfilled the inclusion criteria of the current study. Two reviewers independently identified relevant papers for potential inclusion and assessed the methodological quality.

Results:

This review included 6572 participants in nine countries from three continents (Europe, North America, and Asia). Different studies determined the effects of pollutants on maturation signs and pubertal stages and confirmed the association of organohalogens and phthalates with early puberty.

Conclusion:

Based on the studied literature, environmental pollutants surround and accumulate in human societies and their adverse health effects are well documented. It can be concluded that organohalogens and phthalates are disturbing the normal process of puberty timing; especially their influence on early maturation in girls should be underscored.

Could exposure to phthalates speed up or delay pubertal onset and development? A 1.5-year follow-up of a school-based population

PURPOSE

Phthalates may interfere with the timing of pubertal development in adolescence and existing studies have shown inconsistent results. This study aims to assess the associations of pubertal onset and progression with urinary concentrations of phthalate metabolites in school-aged boys and girls.

METHODS

Using isotope-dilution liquid chromatography tandem mass spectrometry, we analyzed 6 phthalate metabolites in urine samples of 430 children (222 boys and 208 girls) aged 9.7 ± 2.2 years (age range 6.1 to 13.8 years) at baseline and 18 months of follow-up. The associations of exposures to phthalates with pubertal development such as the testis, breast and pubic hair were evaluated using ordered logistic regression models, adjusting for baseline development stage, current chronological age, current body fat composition, and parental education.

RESULTS

Urinary mono-n-butyl phthalate (MnBP) was associated with a 39% increase in the odds of presenting lower pubic hair development stages in boys, and mono (2-ethylhexyl) phthalate (MEHP) (p < 0.10), mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono (2-ethyl-5-oxohexyl) phthalate (MEOHP) were associated with 54%-65% increase in the odds of presenting higher breast development stages in girls (p < 0.05), while MEHHP and MEOHP were also associated with a 70% increase in the odds of menarche onset (p < 0.05). After adjusting for potential confounding variables, the associations of girls' pubertal onset with MnBP, MMP, MEP and MEHP were significant. The odds of girls' breast onset were 4 to 10 times higher in high MnBP, MMP, MEP or MEHP exposure group than in low exposure group.

CONCLUSIONS

Our findings suggest subtle effects of phthalate metabolites associated with pubertal onset and progression. MnBP exposure may be associated with delayed pubic hair development in boys, while MnBP, MMP, MEP, and MEHP exposures may be associated with breast onset, and MEHP metabolites associated with speedup in breast development progression and earlier menarche onset in girls.

Association Between Urinary Phthalates and Pubertal Timing in Chinese Adolescents

BACKGROUND

Phthalates are synthetic chemicals and ubiquitous environmental contaminants, with hormonal activity that may alter the course of pubertal development in children.

OBJECTIVES

To determine whether exposure to phthalate metabolites is associated with timing of pubertal development in a cross-sectional study of a school-based clustered sample of 503 children from a suburban district in Shanghai, China, who were 7-14 years of age at enrollment (2010 October to November).

METHODS

We analyzed six phthalate metabolites in urine samples by isotope-dilution liquid chromatography tandem mass spectrometry. The associations of exposures to phthalates with pubertal timing of testes, breast, and pubic hair development (represented as Tanner stages) were evaluated using an ordered logistic regression model adjusted for chronological age, body fat proportion (BF%), and parental education.

RESULTS

In boys, urinary mono-n-butyl phthalate (MBP) levels were negatively associated with testicular volume, and mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono (2-ethyl-5-oxohexyl) phthalate (MEOHP) levels were negatively associated with pubic hair stages. The odds of being in an advanced stage were decreased by 43%-51%. In girls, mono (2-ethylhexyl) phthalate (MEHP), MEHHP, and MEOHP levels, as well as the sum of these levels, were positively associated with breast stages, and the association was much stronger in girls with high BF%; the odds of being in an advanced stage were increase by 29% to 50%.

CONCLUSIONS

Phthalate metabolites investigated in this study show significant associations with pubertal timing both in boys and in girls, especially among girls with high BF%.

Serum bisphenol A concentration and premature thelarche in female infants aged 4-month to 2-year

OBJECTIVES

To estimate the association between serum bisphenol A and premature thelarche in female infants aged 4-mo to 2-y.

METHODS

A total of 251 female infants (aged 4 mo to 2 y) with premature thelarche and 33 healthy age-matched control subjects were analyzed. All participants underwent physical examination and serum bisphenol A was measured by ultra-performance liquid chromatography tandem mass spectrometry.

RESULTS

Serum bisphenol A concentration in the premature thelarche group (3.48 ng/ml, 95%CI: 0.09-140.26) was significantly higher than that in the control group (1.70 ng/ml, 95%CI: 0.06-51.78) (p = 0.039). There was no correlation between age and serum bisphenol A (BPA) level. Univariate logistic regression analysis showed that serum BPA concentration positively associated with premature thelarche, and the effect of BPA fell down as the age grew.

CONCLUSIONS

This hospital-based study implied that there is an association between serum BPA concentrations and premature thelarche. Additionally, serum BPA levels were markedly higher in infants aged 4-mo to 2-y-old, raising a concern for public health authorities.

Endocrine disrupting chemicals in the atmosphere: Their effects on humans and wildlife

Endocrine disrupting chemicals (EDCs) are exogenous agents that interfere or disrupt the normal synthesis, secretion, transportation, binding and metabolism of natural hormones; eventually dysregulating homeostatic mechanisms, reproduction and development. They are emitted into the atmosphere during anthropogenic activities and physicochemical reactions in nature. Inhalation of these EDCs as particulate and gaseous vapors triggers their interaction with endocrine glands and exerts agonist or antagonists actions at hormone receptors. The endocrine disruption at nanogram levels of EDC's has gained concern in the last decade, due to infertility among men and women, early puberty, obesity, diabetes and cancer. Thus, the review explores the literature that addresses the major occurring EDCs in the atmosphere including phthalates, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), brominated flame retardants (BFRs), dioxins, alkylphenols (APs) and perfluorinated chemicals (PFCs). Sources, fate, half-life, mechanism, measured concentrations in air, bioaccumulation in tissues, laboratory exposures correlating to toxicological effects of these EDCs in humans and wildlife are discussed.

Association between maternal exposure to di(2-ethylhexyl) phthalate and reproductive hormone levels in fetal blood: the Hokkaido study on environment and children's health

Prenatal di(2-ethylhexyl) phthalate (DEHP) exposure can produce reproductive toxicity in animal models. Only limited data exist from human studies on maternal DEHP exposure and its effects on infants. We aimed to examine the associations between DEHP exposure in utero and reproductive hormone levels in cord blood. Between 2002 and 2005, 514 pregnant women agreed to participate in the Hokkaido Study Sapporo Cohort. Maternal blood samples were taken from 23-35 weeks of gestation and the concentration of the primary metabolite of DEHP, mono(2-ethylhexyl) phthalate (MEHP), was measured. Concentrations of infant reproductive hormones including estradiol (E2), total testosterone (T), and progesterone (P4), inhibin B, insulin-like factor 3 (INSL3), steroid hormone binding globulin, follicle-stimulating hormone, and luteinizing hormone were measured from cord blood. Two hundred and two samples with both MEHP and hormones' data were included in statistical analysis. The participants completed a self-administered questionnaire regarding information on maternal characteristics. Gestational age, birth weight and infant sex were obtained from birth records. In an adjusted linear regression analysis fit to all study participants, maternal MEHP levels were found to be associated with reduced levels of T/E2, P4, and inhibin B. For the stratified analyses for sex, inverse associations between maternal MEHP levels T/E2, P4, inhibin B, and INSL3 were statistically significant for males only. In addition, the MEHP quartile model showed a significant p-value trend for P4, inhibin B, and INSL3 decrease in males. Since inhibin B and INSL3 are major secretory products of Sertoli and Leydig cell, respectively, the results of this study suggest that DEHP exposure in utero may have adverse effects on both Sertoli and Leydig cell development in males, which agrees with the results obtained from animal studies. Comprehensive studies investigating phthalates' exposure in humans, as well as their long-term effects on reproductive development are needed.

Urinary phthalates from 168 girls and boys measured twice a year during a 5-year period: associations with adrenal androgen levels and puberty

BACKGROUND

Little is known about the possible deleterious effects of phthalate exposure on endogenous sex steroid levels in children.

OBJECTIVE

Our objective was to investigate whether urinary phthalate metabolite levels are associated with circulating adrenal androgen levels and age at puberty.

METHODS

This was a longitudinal study of 168 healthy children (84 girls) examined every 6 months for 5 years. Serum levels of dehydroepiandrostenedione sulfate (DHEAS), Δ4-androstenedione, testosterone, and urinary morning excretion of 14 phthalate metabolites, corresponding to 7 different phthalate diesters were determined. A variation in urinary excretion of phthalates was evident in each child, which made a mean of repetitive samples more representative for long-term excretion than a single determination.

RESULTS

We found that girls with excretion of monobutyl phthalate isomers (MBP) and di(2-ethylhexyl) phthalate metabolites above the geometric group mean (795 and 730 ng/kg, respectively) had lower levels of DHEAS and Δ4-androstenedione, although statistically significant only at 13 years of age. In boys, we found that excretion of monobenzyl phthalate above the geometric group mean (346 ng/kg) was associated with lower levels of DHEAS at 11 years of age but higher levels of testosterone at 13 years of age. The same trend was observed for MBP excretion, albeit not statistically significant. A lower age at pubarche was observed in boys with excretion of MBP above the geometric group mean (11.0 vs 12.3 years, P = 0.005).

CONCLUSION

Our data indicate that exposure to dibutyl phthalate isomers (DBP) (in girls) and butylbenzyl phthalate (in boys) are negatively associated with adrenal androgen levels and in boys positively associated with testosterone level at 13 years of age. High exposure to DBP was associated with earlier age at pubarche in boys. In girls, no associations between phthalate exposure and age at pubertal milestones were observed.

What is in our environment that effects puberty?

Recent studies indicate that the onset of puberty is occurring at increasingly younger ages. Many etiologies have been hypothesized to be involved, but environmental exposures are among the most worrisome. Multiple organizations have endorsed the need to study and provide clinical awareness regarding the effect of a child's environment on pubertal timing. This review article summarizes the current understanding of the major environmental influences on pubertal timing, focusing on factors for which the most scientific evidence exists. The research reviewed addresses intrinsic factors unique to each individual, naturally occurring endocrine disruptors and chemical endocrine disruptors. In each category, evidence was found for and against the involvement of specific environmental factors on pubertal timing. Ultimately, an individual's environment is likely comprised of many aspects that collectively contribute to the timing of puberty. The need for research aimed at elucidating the effects of numerous specific yet disparate forms of exposures is emphasized.

Reproductive and developmental effects of phthalate diesters in females

Phthalate diesters, widely used in flexible plastics and consumer products, have become prevalent contaminants in the environment. Human exposure is ubiquitous and higher phthalate metabolite concentrations documented in patients using medications with phthalate-containing slow release capsules raises concerns for potential health effects. Furthermore, animal studies suggest that phthalate exposure can modulate circulating hormone concentrations and thus may be able to adversely affect reproductive physiology and the development of estrogen sensitive target tissues. Therefore, we conducted a systematic review of the epidemiological and experimental animal literature examining the relationship between phthalate exposure and adverse female reproductive health outcomes. The epidemiological literature is sparse for most outcomes studied and plagued by small sample size, methodological weaknesses, and thus fails to support a conclusion of an adverse effect of phthalate exposure. Despite a paucity of experimental animal studies for several phthalates, we conclude that there is sufficient evidence to suggest that phthalates are reproductive toxicants. However, we note that the concentrations needed to induce adverse health effects are high compared to the concentrations measured in contemporary human biomonitoring studies. We propose that the current patchwork of studies, potential for additive effects and evidence of adverse effects of phthalate exposure in subsequent generations and at lower concentrations than in the parental generation support the need for further study.

The association between phthalate exposure and asthma

Asthma is a chronic inflammatory disorder of the airway, characterized by airway hyperresponsiveness. It is a disabling disease with an increasing prevalence, resulting in heavy social and economic burdens worldwide. Humans are extensively exposed to phthalates, and many epidemiological studies have shown a relationship between phthalate exposure and asthma in recent decades. Earlier experimental studies focused on inflammatory cells, demonstrating the adjuvant effects, immunomodulatory effects, or immunosuppressive effects related to phthalate exposure. Recent studies have shown that phthalates may have a direct effect on airway epithelial cells and contribute to airway remodeling, which is the cardinal pathologic characteristic of chronic asthma, with a high correlation with disease severity. Through these efforts, phthalates have been recognized as important environmental factors in the pathogenesis of asthma, but further studies are still required to elucidate the detailed mechanism. This review discusses the current status of human exposure to phthalates in Taiwan and summarizes the epidemiological and experimental evidence related to the roles of phthalate exposure in the development of asthma and associated diseases.

Plasticizer incident and its health effects in Taiwan

The May 23, 2011, plasticizer incident was one of the most serious food safety issues that ever occurred in Taiwan. Most, if not all, plasticizer-contaminated food items were due to malicious replacement of palm oil with phthalate plasticizer(s) in the cloudy-agent formulas by two upstream manufacturers. The incumbent agencies in Taiwan took necessary actions to minimize the harm caused by the incident and to ease the panic of the general public. In this paper, the incident was briefly reviewed and the situations of phthalate exposure in general public and pregnant women were assessed. Subsequently, the associations between phthalates exposure and the adverse health effects, such as shortened anogenital distance in baby boys, premature thelarche in young girls, endometriosis, adenomyosis, and leiomyoma in women, and decreased semen quality in men, were discussed. Food safety issue has become a worldwide concern and early detection of potential new toxicants in the foods is indispensable. Therefore, it is imperative to establish an international network for early warning or sentinel on food safety.