Association of phthalate exposure and endogenous hormones with self-reported sleep disruptions: results from the Midlife Women's Health Study

Exploring the Association Between Sleep Patterns, Pubertal Health, and Phthalate Exposure-Preliminary Results from Slovakia

BACKGROUND

This study aims to explore the association between sleep patterns in children and their exposure to phthalates to assess potential health implications.

METHODS

Participants (n = 60) completed the Pittsburgh Sleep Quality Index (PSQI) questionnaire. Consumer behavior scores (CBS) were calculated. The Tanner scale was used to monitor the stages of puberty. First-morning urine samples were analyzed by high-performance liquid chromatography-tandem mass spectrometry.

RESULTS

The average sleep duration was 8 h and 44 min, with boys sleeping significantly longer (p = 0.01). Notably, 51.7% of participants reported sleeping less than 9 h. The nonlinear effects of phthalate metabolite in association with PSQI were observed for hydroxy-mono-isononyl phthalate (OH-MiNP, p = 0.003) and MnOP (p < 0.001), indicating that the relationship does not follow a simple linear pattern. Simple linear regression revealed a significant positive association between the Mono-n-octyl phthalate (MnOP) and PSQI scores (p = 0.016). After adjustment for place of residence, BMI, CBS, sex, and age, the significance of associations between phthalate metabolites and sleep quality diminished, necessitating cautious interpretation. No statistically significant associations between pubertal changes and the value of PSQI as well as phthalates were observed.

CONCLUSION

Our results provide preliminary evidence of potential nonlinear associations that require validation in a larger cohort. The findings highlight the importance of monitoring phthalate exposure in children, as it may influence sleep patterns and overall health.

Moderating effects of insomnia on the association between urinary phthalate metabolites and depressive symptoms in Chinese college students: focus on gender differences

OBJECTIVES

To investigate the rates of depressive symptoms in college students, explore the relationship between urinary phthalate metabolites and depressive symptoms and their gender differences, and further explore the moderating role of insomnia in this association.

METHODS

A total of 1 179 college students were recruited from 2 universities in Hefei and Shangrao cities from April to May 2019. The depressive symptoms and insomnia of college students were investigated by the Patient Health Questionnaire 9 and Insomnia Severity Index. The high-performance liquid chromatography-tandem mass spectrometry was adapted to determine the concentration of urinary phthalate metabolites. The generalized linear model was used to analyze the relationship of phthalate metabolites with depressive symptoms. Moderating analysis was used to examine whether insomnia moderated the relationship of phthalate metabolites with depressive symptoms.

RESULTS

The rates of mild depression, and moderate depression and above in college students were 31.9% and 9.2%, respectively. The phthalate metabolites exhibited a median and mean concentration spanning from 2.98 ∼ 156.55 ng/mL and 6.12 ∼ 205.53 ng/mL. The generalized linear model results showed that monobutyl phthalate (MBP) (β = 1.160, 95%CI: 0.423 ∼ 1.896) and low molecular weight phthalate (LMWP) (β = 1.230, 95%CI: 0.348 ∼ 2.113) were positively correlated with depressive symptoms, and MBP (β = 1.320, 95%CI: 0.453 ∼ 2.187) and LMWP (β = 1.396, 95%CI: 0.351 ∼ 2.440) were positively correlated with depressive symptoms only in female college students after stratified by gender. Furthermore, insomnia has a positive moderating role between MBP, LMWP, and depressive symptoms and has a sex-based difference.

CONCLUSIONS

This study suggests that there is a positive association of phthalate metabolites with depressive symptoms among Chinese college students, as well as insomnia plays a positive moderating role in this association.

Phthalates are detected in the follicular fluid of adolescents and oocyte donors with associated changes in the cumulus cell transcriptome

OBJECTIVE

To investigate the follicular fluid (FF) phthalate levels in adolescents undergoing fertility preservation compared with oocyte donors and explore its association with ovarian reserve and cumulus cell (CC) gene expression.

DESIGN

Retrospective study and molecular analysis of CCs and FF.

SUBJECTS

Adolescents (n = 20, 16.7 ± 0.6 years) undergoing fertility preservation and oocyte donors (n = 24, 26.2 ± 0.4 years).

EXPOSURE

Not applicable.

MAIN OUTCOME MEASURES

Patient demographics, ovarian stimulation, and oocyte retrieval outcomes were analyzed for each group. The FF levels of 9 phthalate metabolites were assessed individually and as molar sums representative of common compounds (all phthalates, ƩPhthalates; di(2-ethylhexyl) phthalate (DEHP)-associated phthalate metabolites, ƩDEHP), exposure sources (plastics, ƩPlastic; personal care products, ƩPCP), and modes of action (antiandrogenic, ƩAA) and compared between the 2 groups. The transcriptome of CC associated with mature oocytes was compared between adolescents and oocyte donors using bulk ribonucleic acid sequencing.

RESULTS

The FF ƩPlastic and ƩPCP levels were significantly higher in adolescents than in oocyte donors. The FF ƩDEHP, ƩPlastic, ƩPCP, ƩAA, and ƩPhthalates levels were positively associated with antral follicle count in oocyte donors when adjusted for age, body mass index, and race/ethnicity. Ribonucleic acid sequencing analysis revealed 248 differentially expressed genes in CCs of adolescents within the top quartile (n = 4) of the FF ƩPhthalates levels compared with those of the adolescents within the bottom half (n = 9). Genes enriched in pathways involved in cell motility and development were significantly down-regulated.

CONCLUSIONS

Adolescents undergoing fertility preservation cycles demonstrate higher levels of phthalate metabolites in their FF than oocyte donors. Higher phthalate levels are associated with alterations in cumulus cells transcriptome in adolescents. The phthalate metabolite levels in FF are associated with higher antral follicle count levels in oocyte donors.

Adverse effects of diethyl phthalate and butyl benzyl phthalate on circadian rhythms and sleep patterns in zebrafish larvae

The zebrafish, a diurnal vertebrate, is commonly used in circadian rhythm studies due to its genetic and neurological similarities to humans. Circadian rhythms, which regulate sleep, neurotransmitter, behavior, and physiological responses to environmental changes, can be disrupted by various environmental factors. Phthalic acid esters (PAEs) are pervasive endocrine disruptors that individuals are frequently exposed to in daily life. However, the impact of PAEs on circadian rhythms during early development remains poorly understood. This study aimed to investigate the effects of exposure to diethyl phthalate (DEP) and butyl benzyl phthalate (BBzP) on the behavior and circadian rhythms of developing zebrafish larvae using a series of layered assays. Zebrafish larvae were exposed to the two PAEs from less than 2 hour post-fertilization (hpf) until 96 hpf. The results demonstrated a concentration-dependent reduction in tail coiling (TC), touch-evoked response (TER), and locomotor activity, alongside an increase in sleep time and alterations in sleep bouts and sleep latency during both 24-hour and Light1/Dark/Light2 (7/10/7-hour) periods. Additionally, exposure to BBzP led to increased acetylcholinesterase (AChE) and dopamine (DA) levels, and a decrease in 5-hydroxytryptamine (5-HT) levels. Gene expression analysis revealed that DEP and BBzP exposure increased the expression of circadian rhythm and light-response-related genes. In conclusion, exposure to these PAEs disrupts the circadian rhythm of zebrafish larvae, providing novel insights into the developmental impact of these common environmental contaminants. Further research is needed to understand the broader implications of these findings for human health and environmental safety.

Association of Di(2-ethylhexyl) Phthalate Exposure with Reproductive Hormones in the General Population and the Susceptible Population: A Systematic Review and Meta-Analysis

Di(2-ethylhexyl) phthalate (DEHP), an environmental endocrine disruptor, has hormone-like activity and endocrine-disrupting effects. However, the types of reproductive hormones associated with DEHP vary across the studies. Thus, we conducted a systematic review and meta-analysis to pool existing epidemiological evidence. We searched three databases up to January 31, 2024, for eligible original studies to ultimately include 37 studies from eight countries with a total of 28 911 participants. DEHP exposure was evaluated with urinary metabolites. Since the main types, production sites, blood concentrations, and functions of reproductive hormones differ between men and women, we reported the combined effect values by gender. Subgroup analyses were conducted by age, subfertility status, and the national sociodemographic index (SDI) level. Furthermore, the effect of maternal exposure during pregnancy on children's reproductive hormone levels was analyzed separately. Overall, in general, in men, DEHP was positively correlated with sex hormone binding-globulin (SHBG) and adversely correlated with total testosterone (TT), free androgen index (FAI), and follicle-stimulating hormone (FSH). Results indicated that among men of reproductive age, DEHP exposure was associated with more significant hormonal suppression in infertile men compared with fertile men. Notably, age subgroup analysis among women revealed that postmenopausal women were more vulnerable to DEHP, which was related to lower TT and estradiol (E2). However, this study did not observe a significant association between prenatal DEHP metabolites and reproductive hormone levels in children. Our research identifies the most susceptible hormones (androgen suppression) after DEHP exposure and suggests that infertile men and postmenopausal women are in great need of more attention as sensitive populations.

Biopsychosocial factors intersecting with weekly sleep difficulties in the menopause transition

OBJECTIVES

Sleep difficulties are common in the menopause transition and increase risk for a variety of physical and psychological problems. The current study investigated potential interactions between psychosocial variables and within-person changes in ovarian hormones in predicting perimenopausal sleep problems as well as the potential interactions between poor sleep and psychosocial factors in predicting worsened mood, affect, and attention.

STUDY DESIGN

The sample included 101 perimenopausal individuals. Participants completed 12 weekly assessments of self-reported sleep outcomes, depressive mood and affect, and attention function, and of estrone glucuronide (E1G) and pregnanediol glucuronide (PdG) levels (urinary metabolites of estradiol and progesterone, respectively); they also had 24-h tracking of vasomotor symptoms. Other psychosocial variables such as trauma history and stressful life events were assessed at baseline.

RESULTS

A history of depression, baseline depressive symptoms, trait anxiety, and more severe and bothersome vasomotor symptoms predicted worsened sleep outcomes. Recent stressful life events, trauma history, and person-centred E1G and PdG changes did not predict sleep outcomes. However, there was an interaction whereby person-centred E1G decreases predicted lower sleep efficiency in those with higher baseline depressive symptoms. Higher baseline depression and trauma history also amplified the effect of vasomotor symptoms on sleep outcomes. In evaluating the effect of poor sleep on psychological and cognitive outcomes, stressful life events emerged as a moderating factor. Finally, trauma history and poor sleep interacted to predict worsened attention function.

CONCLUSIONS

The current study suggests that certain individuals may be at greater risk of perimenopausal sleep problems and the resulting negative effects on mood and cognition.

Gender- and Obesity-Specific Association of Co-Exposure to Personal Care Product and Plasticizing Chemicals and Short Sleep Duration among Adults: Evidence from the National Health and Nutrition Examination Survey 2011-2016

There is limited evidence about the gender- and obesity-specific effects of personal care product and plasticizing chemicals (PCPPCs) on short sleep duration in adults. We evaluated the gender- and obesity-specific association of co-exposure to PCPPCs and short sleep duration among adults aged 20-60 years using the National Health and Nutrition Examination Survey (NHANES) 2011-2016, a secondary data source from the United States. Seventeen PCPPCs, including five phenols, two parabens, and ten phthalates, were detected, and sleep duration was assessed among 3012 adults. Logistic regression, weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR) were employed. We found that bisphenol A (BPA), mono (caboxy-isooctyl) phthalate (MCOP), and mono (3-carboxypropyl) phthalate (MCPP) were consistently positively associated with short sleep duration in both females and males regardless of obesity status, except for BPA with general obesity. In particular, mono benzyl phthalate (MBzP) revealed a positive association in females, mono (2-ethyl-5-oxohexyl) phthalate (MEOHP) revealed a positive association in males, and MiBP revealed a positive association in abdominal obesity. Similar associations were observed in the mixture. Our study highlights that PCPPCs are independently associated with an increasing risk of short sleep duration in adults both individually and as a mixture; however, gender- and obesity-specific differences may have little effect on certain individual PCPPCs on short sleep duration.

An influence of menopausal symptoms on mental health, emotion perception, and quality of life: a multi-faceted approach

PURPOSE

The menopausal transition brings with it many physical, cognitive, and affective changes in a woman's life, impacting quality of life. Whereas prior work has examined impact on general mental health and cognitive function, research on basic affective processing during menopause remains scarce.

METHODS

Using a median-split procedure, this pre-registered study examined the impact of stronger (N = 46 women) vs. milder (N = 47 women) menopausal symptoms using a behavioural task of subjective emotion perception (embody) and a passive eye tracking viewing task of emotional faces in addition to self-report questionnaires. After 3 months, participants completed the questionnaires again to examine whether objective measures of emotion perception (eye tracking) might predict mental health at follow-up.

RESULTS

As anticipated, women with stronger vs. milder menopausal symptoms reported increased symptoms of anxiety, depression, stress, emotion regulation difficulties, and lower quality of life during both time points. While no evidence was found in the behavioural task, eye tracking data indicated blunted emotion perception in women with high menopausal symptoms, while women with low symptoms spent more time looking at happy faces relative to fearful or surprised faces. Although eye tracking or hormonal data did not predict mental health at follow-up, a higher estradiol/FSH ratio indicated a higher quality of life.

CONCLUSIONS

This study documented an impact of the menopausal transition and strength of menopausal symptoms in particular on objective emotion perception as well as mental health and quality of life in women suffering from stronger vs. milder menopausal symptoms. Clinical implications are discussed.

Association between phthalates and sleep problems in the U.S. adult females from NHANES 2011-2014

There is little research on the relationship between phthalates exposure and sleep problems in adult females, with existing studies only assessing the association between exposure to individual phthalates with sleep problems.     We aimed to analyse the relationship between phthalates and sleep problems in 1366 US females aged 20 years and older from the 2011-2014 National Health and Nutrition Examination Survey (NHANES) by age stratification. Multivariate logistic regression showed that the fourth quartile of MECPP increased the risk of sleep problems in females aged 20-39 compared with the reference quartile (OR: 1.87, 95% CI: 1.14, 3.08). The WQS index was significantly associated with the sleep problems in females aged 20-39. In the BKMR, a positive overall trend between the mixture and sleep problems in females aged 20-39. In this study, we concluded that phthalates might increase the risk of sleep problems in females aged 20-39.

Impact of climate and environmental change on the menopause

The huge impact of climate change on humankind is multidimensional, and includes direct and indirect challenges to the physical, psychological and socio-cultural wellbeing. Women may be more vulnerable to climate-sensitive diseases, but little attention has been paid to specific needs and challenges associated with the menopause transition. The increase in average and extreme temperatures may modulate the manifestation of vasomotor symptoms; in particular, environmental temperature and seasonality may affect hot flushes and night sweats. However, more research is needed to define the impact of climate-related factors among the determinants influencing the individual experience of menopause. In addition, increased exposure to environmental pollution and toxins may also have a role in the modulation of ovarian aging mechanisms, possibly influencing timing of menopause. Finally, both air pollution and menopause transition are associated with unfavorable modifications of cardio-metabolic, bone and cognitive health, and account should be taken of these in the evaluation of the individual woman's health vulnerabilities. Overall, the evidence reported in this narrative review supports the need for specific strategies aimed at reducing the burden of climate and environmental change on menopausal women. Healthcare providers should promote behavioral measures that reduce anthropogenic climate change and at the same time have a beneficial role on several domains of physical and psychological wellbeing. From this perspective, menopause represents a golden moment to implement virtuous behaviors that will benefit at the same time women's longevity and the planet.

Cross-sectional associations between phthalates, phenols, and parabens with metabolic syndrome risk during early-to-mid adolescence among a cohort of Mexican youth

BACKGROUND

Epidemiological studies on children and adults have linked toxicants from plastics and personal care products to metabolic disruption. Yet, the impact of endocrine-disrupting chemicals (EDCs) on adolescent metabolic syndrome (MetS) risk during early and mid-adolescence is unclear.

METHODS

To examine the links between exposure to EDCs and MetS risk and its components, cross-sectional data from 344 Mexican youth in early-to-mid adolescence (10-17 years) were analyzed. Urinary biomarker concentrations of phthalates, phenol, and paraben analytes were measured from a single spot urine sample collected in 2015; study personnel obtained anthropometric and metabolic measures. We examined associations between summary phthalates and metabolites, phenol, and paraben analytes with MetS risk z-scores using linear regression, adjusted for specific gravity, sex, age, pubertal status, smoking, alcohol intake, physical activity level, and screen time. As a secondary aim, mediation analysis was conducted to evaluate the role of hormones in the association between summary phthalates with lipids and MetS risk z-scores.

RESULTS

The mean (SD) age was 13.2 (1.9) years, and 50.9% were female. Sex-stratified analyses revealed associations between summary phthalates and lipids ratio z-scores, including Σ DEHP [β = 0.21 (95% CI: 0.04, 0.37; p < 0.01)], phthalates from plastic sources (Σ Plastic) [β = 0.22 (95% CI: 0.05, 0.39; p < 0.01)], anti-androgenic phthalates (Σ AA) [β = 0.22 (95% CI: 0.05, 0.39; p < 0.01)], and individual phthalate metabolites (MEHHP, MEOHP, and MECPP) among males. Among females, BPA [β = 0.24 (95% CI: 0.03, 0.44; p < 0.05)] was positively associated with lipids ratio z-score and one phenol (2,5 DCP) [β = 0.09 (95% CI: 0.01, 0.18); p < 0.05)] was associated with increased waist circumference z-score. Results showed no evidence of mediation by hormone concentrations in the association between summary phthalates with lipids ratio or MetS risk z-scores.

CONCLUSION

Higher EDC exposure was positively associated with serum lipids during adolescence, particularly among males.

Is exposure to chemical pollutants associated with sleep outcomes? A systematic review

Environmental exposures may influence sleep; however, the contributions of environmental chemical pollutants to sleep health have not been systematically investigated. We conducted a systematic review to identify, evaluate, summarize, and synthesize the existing evidence between chemical pollutants (air pollution, exposures related to the Gulf War and other conflicts, endocrine disruptors, metals, pesticides, solvents) and dimensions of sleep health (architecture, duration, quality, timing) and disorders (sleeping pill use, insomnia, sleep-disordered breathing)). Of the 204 included studies, results were mixed; however, the synthesized evidence suggested associations between particulate matter, exposures related to the Gulf War, dioxin and dioxin-like compounds, and pesticide exposure with worse sleep quality; exposures related to the Gulf War, aluminum, and mercury with insomnia and impaired sleep maintenance; and associations between tobacco smoke exposure with insomnia and sleep-disordered breathing, particularly in pediatric populations. Possible mechanisms relate to cholinergic signaling, neurotransmission, and inflammation. Chemical pollutants are likely key determinants of sleep health and disorders. Future studies should aim to evaluate environmental exposures on sleep across the lifespan, with a particular focus on developmental windows and biological mechanisms, as well as in historically marginalized or excluded populations.

Associations between exposure to phthalates, phenols, and parabens with objective and subjective measures of sleep health among Mexican women in midlife: a cross-sectional and retrospective analysis

Endocrine-disrupting chemicals (EDCs) may impact sleep during the menopausal transition by altering sex hormones. However, these studies are scarce among Latin American women. This investigation utilized cross-sectional and retrospective data from midlife women enrolled in the Early Life Exposure in Mexico to Environmental Toxicants (ELEMENT) study to examine associations between exposure to EDCs (phthalates, phenols, and parabens) and sleep health measures. For cross-sectional analyses, single spot urine samples were collected between 2017-2019 from a pilot sample of women (N = 91) of midlife age to estimate the urinary concentration of individual phthalates, phenols, and parabens and to calculate the summary concentration of phthalate mixtures. Seven-day nightly sleep duration, midpoint, and fragmentation were obtained from wrist-actigraphy devices and estimated from the actigraphy data using a pruned dynamic programming algorithm. Self-reported poor sleep quality was assessed by one item from the Pittsburgh Sleep Quality Index (PSQI). We examined associations between urinary summary phthalate mixtures, phthalate metabolites, phenol, and paraben analytes with each sleep measure using linear or logistic (to compute odds of poor sleep quality only) regression models adjusted for specific gravity, age, and socioeconomic status. We ran similar regression models for retrospective analyses (N = 74), except that urine exposure biomarker data were collected in 2008 when women were 24-50 years old. At the 2017-2019 midlife visit, 38% reported poor sleep quality. Cross-sectionally, EDCs were associated with longer sleep duration, earlier sleep timing, and more fragmented sleep. For example, every 1-unit IQR increase in the phenol triclosan was associated with a 26.3 min per night (95% CI: 10.5, 42.2; P < 0.05) longer sleep duration and marginally associated with 0.2 decimal hours (95% CI: -0.4, 0.0; P < 0.10) earlier sleep midpoint; while every 1-unit IQR increase in the phthalate metabolite MEHP was associated with 1.1% higher sleep fragmentation (95% CI: 0.1, 2.1; P < 0.05). Retrospective study results generally mirrored cross-sectional results such that EDCs were linked to longer sleep duration, earlier sleep timing, and more fragmented sleep. EDCs were not significantly associated with odds of self-reported poor sleep quality. Results from cross-sectional and retrospective analyses revealed that higher exposure to EDCs was predictive of longer sleep duration, earlier sleep timing, and more fragmented sleep among midlife women.

Does the environment affect menopause? A review of the effects of endocrine disrupting chemicals on menopause

Endocrine disrupting chemicals are widely distributed in our environment. Humans are exposed to these compounds not only through their occupations, but also through dietary consumption and exposure to contaminated water, personal care products and textiles. Chemicals that are persistent in the body and in our environment include dioxins and polychlorinated biphenyls. Non-persistent chemicals including bisphenol A, phthalates and parabens are equally as important because they are ubiquitous in our environment. Heavy metals, including lead and cadmium, can also have endocrine disrupting properties. Although difficult to study due to their variety of sources of exposures and mechanisms of action, these chemicals have been associated with early menopause, increased frequency of vasomotor symptoms, altered steroid hormone levels and markers of diminished ovarian reserve. Understanding the impacts of these exposures is important given the potential for epigenetic modification, which can alter gene function and result in multi-generational effects. This review summarizes findings in humans and animals or cell-based models from the past decade of research. Continued research is needed to assess the effects of mixtures of chemicals, chronic exposures and new compounds that are continuously being developed as replacements for toxic chemicals that are being phased out.

Urinary phthalates, phenols, and parabens in relation to sleep health markers among a cohort of Mexican adolescents

INTRODUCTION

Emerging research has shed light on the potential impact of environmental toxicants on sleep health, however, it remains unclear if these associations exist during adolescence and whether associations differ by sex. This study aimed to examine associations between phthalates, parabens, and phenols on adolescent sleep health using cross-sectional data from 470 participants from the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) study.

MATERIAL AND METHODS

In 2015, spot urine samples were analyzed for exposure biomarkers of 14 phthalate metabolites, seven phenol, and four paraben analytes. Over seven consecutive days, sleep duration, midpoint, and fragmentation were assessed with wrist-actigraphy. We examined associations between summary phthalates, individual phthalate metabolites, and phenol and paraben analytes with mean weekday sleep duration, midpoint, and fragmentation using linear regression models adjusted for specific-gravity and sex, age, pubertal status, smoking and alcohol behavior, physical activity, and screen time.

RESULTS

Mean (SD) age was 13.8 (2.1) years; 53.5 % were female. Σ Plastic - summary measure for toxicants from plastic sources - and Σ DEHP and its metabolites, were associated with longer sleep duration in the unstratified sample. To illustrate, every 1-unit log increase in Σ DEHP was associated with 7.7 min (95 % CI: 0.32, 15.1; p < 0.05) longer duration. Summary measures of toxicants from plastic sources, personal care products, anti-androgenic toxicants, and multiple individual phthalates, phenols, and parabens were associated with later midpoint. The midpoint associations were largely female-specific. There were no associations with sleep fragmentation.

CONCLUSIONS

Higher EDC exposure may be related to longer sleep duration and later sleep timing during adolescence, and associations may vary by toxicant and according to sex.

Associations of individual and cumulative urinary phthalate and replacement biomarkers with gestational weight gain through late pregnancy

BACKGROUND/AIMS

Phthalates and their replacements are endocrine/metabolic disruptors that may impact gestational weight gain (GWG) - a pregnancy health indicator. We investigated overall and fetal sex-specific associations of individual and cumulative phthalate/replacement biomarkers with GWG.

METHODS

Illinois women (n = 299) self-reported their weight pre-pregnancy and at their final obstetric appointment before delivery (median 38 weeks). We calculated pre-pregnancy body mass index and gestational age-specific GWG z-scores (GWGz). We quantified 19 phthalate/replacement metabolites (representing 10 parent compounds) in pools of up-to-five first-morning urine samples, collected approximately monthly between 8 and 40 weeks gestation. We used linear regression, quantile-based g-computation (QGComp), and weighted quantile sum regression (WQSR) to evaluate associations of ten biomarkers (individual metabolites or parent molar-sums) individually or as mixtures (in interquartile range intervals) with GWGz. We evaluated associations in all women and stratified by fetal sex.

RESULTS

Individually, sums of metabolites of di(2-ethylhexyl) phthalate (ƩDEHP), di(isononyl) cyclohexane-1,2-dicarboxylate (ƩDiNCH), and di(2-ethylhexyl) terephthalate (ƩDEHTP) had consistent inverse associations with GWGz, and some associations were fetal sex-specific. When evaluating phthalates/replacements as a mixture, QGComp identified ƩDEHP, ƩDEHTP, and mono-(3-carboxypropyl) phthalate, along with sum of di(isononyl) phthalate metabolites (ƩDiNP) and monobenzyl phthalate as notable contributors to lower and higher GWGz, respectively, resulting in a marginal inverse joint association in all women (β: -0.29; 95% CI: -0.70, 0.12). In women carrying females, ƩDEHP contributed to the marginal inverse joint association (β: -0.54; 95% CI: -1.09, 0.03). However, there was no overall association in women carrying males (β: 0.00; 95% CI: -0.60, 0.59), which was explained by approximately equal negative (driven by ƩDEHTP) and positive (driven by ƩDiNP) partial associations. WQSR analyses consistently replicated these QGComp findings.

CONCLUSIONS

Biomarkers of phthalates/replacements were fetal sex-specifically associated with GWGz. Because ƩDEHTP contributed substantively to mixture associations, additional studies in pregnant women may be needed around this plasticizer replacement.

Nocturnal Hot Flashes, but Not Serum Hormone Concentrations, as a Predictor of Insomnia in Menopausal Women: Results from the Midlife Women's Health Study

Background: Sleep disruptions are among the most common symptoms experienced during menopause and can be associated with depression, hot flashes, and fluctuating hormones. However, few studies have examined how such risk factors influence sleep in midlife women in a network-based approach that will establish the complex relationship between variables. Materials and Methods: We used a Bayesian network (BN) to examine the relationship between multiple factors known to influence sleep and depression in midlife women, including hormone concentrations, hot flashes, and menopause status among participants of the longitudinal Midlife Women's Health Study. In year 1, 762 women (45-54 years of age) answered questions regarding the frequency of insomnia, hot flashes, and depression; 389 of the same women answered similar questions at year 4. We measured serum hormones and calculated free estradiol index, free testosterone index, and ratios of estradiol:progesterone, and estradiol:testosterone. For our model, we calculated the change in frequency of insomnia, depression, and covariates (body mass index, menopause status, hot flashes at night, and present quality of life) from year 1 to 4. Results: Using a BN, we found that self-reported hot flashes at night, and no other factors, were direct predictors of self-reported insomnia in year 1. Surprisingly, we did not identify an association between hormone concentrations and self-reported insomnia. Frequency of insomnia in year 4 was only predicted by frequency of insomnia in year 1, whereas frequency of depression in year 4 was predicted by year 4 insomnia and frequency of depression in year 1. No other factors were direct predictors of insomnia or depression in our model. Conclusions: Therefore, hot flashes at night, previous insomnia, and depression are stronger predictors of how women will self-report frequency of sleep disruptions and treatment may reduce menopausal sleep complaints.

The role of ovarian hormones in the pathophysiology of perimenopausal sleep disturbances: A systematic review

Sleep disturbance is a common clinical concern throughout the menopausal transition. However, the pathophysiology and causes of these sleep disturbances remain poorly understood, making it challenging to provide appropriate therapy. Our goal was to i) review the literature about the influence of ovarian hormones on sleep in perimenopausal women, ii) summarize the potential underlying pathophysiology of menopausal sleep disturbances and iii) evaluate the implications of these findings for the therapeutic approach to sleep disturbances in the context of menopause. A systematic literature search using the databases Embase, MEDLINE and Cochrane Library was conducted. Keywords relating to ovarian hormones, sleep disturbances and menopause were used. Ultimately, 86 studies were included. Study Quality Assessment Tools of the National Institutes of Health were used for quality assessment. Results from good-quality studies demonstrated that the postmenopausal decline in estrogen and progesterone contributes to sleep disturbances in women and that timely treatment with estrogen and/or progesterone therapy improved overall sleep quality. Direct and indirect effects of both hormones acting in the central nervous system and periphery, as well as via secondary effects (e.g. reduction in vasomotor symptoms), can contribute to improvements in sleep. To strengthen external validity, studies examining neurobiological pathways are needed.

The Relationship Between Daily Dietary Intake of Fiber and Short Sleep Duration in the Presence of Di(2-Ethylhexyl) Phthalate: A Population-Based Study

Objective

This study aimed to evaluate the relationship between daily dietary intake of fiber (DDIF) and short sleep duration (SSD) in the presence of di(2-ethylhexyl) phthalate.

Methods

Data of 13,634 participants in this study were collected from the National Health and Nutrition Examination Survey (NHANES). The sum of urinary mono-2-ethyl-5-carboxypentyl phthalate, mono-(2-ethyl-5-hydroxyhexyl) phthalate, mono-(2-ethyl)-hexyl phthalate, and mono-(2-ethyl-5-oxohexyl) phthalate was used to evaluate the level of di(2-ethylhexyl) phthalate (DEHP) exposure. The ln-transformed urinary creatinine-corrected DEHP [ln(DEHP/UCr)] level was used in the statistical models. DDIF was divided into tertiles (<5.77 g/1,000 kcal, 5.77–9.04 g/1,000 kcal, and ≥9.04 g/1,000 kcal).

Results

The 13,634 participants included in this study were classified into two groups according to sleep duration. The dose response analysis showed that higher ln(DEHP/UCr) was related to a higher risk of SSD (<7 h and <6 h). Participants in the highest vs. the lowest quartile of DEHP were found to be at increased risk of SSD (<7 h, <6 h, and <5 h). The result of risk of SSD <7 h was OR 1.57, 95% CI, 1.40–1.76; P_trend <0.001, of SSD <6 h was OR 1.38, 95% CI, 1.18–1.61; P_trend <0.001, and of SSD <5 h was OR 1.45, 95% CI, 1.13–1.86; P_trend <0.001. DEHP exposure was found to be associated with SSD <7 h in a sex-specific manner (P_interaction = 0.033). A significant interaction between ln(DEHP/UCr) and DDIF_{(tertiles1 vs. tertiles2)} (P_interaction = 0.02) was detected for SSD <7 h.

Conclusion

Our results showed that there was a harmful association between DEHP exposure and SSD (<7 h, <6 h, and <5 h). The ameliorative effects of median level of DDIF on SSD <7 h in the presence of DEHP exposure were observed in this study.

Preliminary findings reveal that phthalate exposure is associated with both subjective and objective measures of sleep in a small population of midlife women

Phthalates are endocrine-disrupting chemicals that influence endogenous hormones. Few studies have examined the link between phthalates and menopause. A recent secondary analysis revealed that phthalates were associated with self-reported sleep measures in perimenopausal women. However, the associations between phthalate exposure and additional measures of sleep remain unknown. We recruited a population of 27 midlife women (aged 45-54) to study the relationship between phthalate exposure and both subjective and objective measures of sleep. Preliminary results indicate that women with higher phthalate exposure have reduced sleep quality, more frequent sleep disruptions, and more restless sleep compared to women with lower exposure.

The Effects of Environmental Contaminant Exposure on Reproductive Aging and the Menopause Transition

PURPOSE OF REVIEW

Menopause marks the end of a woman's reproductive lifetime. On average, natural menopause occurs at 51 years of age. However, some women report an earlier age of menopause than the national average. This can be problematic for women who delay starting a family. Moreover, early onset of menopause is associated with increased risk of cardiovascular disease, depression, osteoporosis, and premature death. This review investigates associations between exposure to endocrine-disrupting chemicals (EDCs) and earlier onset of menopause.

RECENT FINDINGS

Recent data suggest exposure to certain EDCs may accelerate reproductive aging and contribute to earlier onset of menopause. Human and rodent-based studies identify positive associations between exposure to certain EDCs/environmental contaminants and reproductive aging, earlier onset of menopause, and occurrence of vasomotor symptoms. These findings increase our understanding of the detrimental effects of EDCs on female reproduction and will help lead to the development of strategies for the treatment/prevention of EDC-induced reproductive aging.

Ovarian Toxicity and Epigenetic Mechanisms of Phthalates and Their Metabolites

Ovary plays an important role in the female reproductive system. The maintenance and regulation of ovarian function are affected by various physical and chemical factors. With the development of industrialization, environmental pollutants have caused great harm to public health. Phthalates, as a class of endocrine-disrupting chemicals (EDCs), are synthesized and used in large quantities as plasticizers due to their chemical properties. They are easily released into environment because of their noncovalent interactions with substances, causing human exposure and possibly impairing ovary. In recent years, more and more attention has been paid to the role of epigenetics in the occurrence and development of diseases. And it is urgent to study the role of methylation, gene imprinting, miRNA, and other epigenetic mechanisms in reproductive toxicology.