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

The prevalent trajectory of early menopause associated with PM2.5 exposure across 1956-2018 extrapolated from LightGBM algorithm

BACKGROUND

Fine particulate matter (PM2.5) is noxious to female reproductive development and facilitates the occurrence of subsequent diseases. Early menopause is initiative factor of female aging. But due to the lack of historical exposure of PM2.5, we could not gain insight into the linkage between ambient PM2.5 exposure and early menopause.

METHODS

We conducted a community-based retrospective cross-sectional study and pooled 1173 postmenopausal women. The machine learning algorithm of LightGBM was processed to derive the historical concentrations of PM2.5 based on aerography of 1956-2022. The quantile g-computation and binary logistic regression were employed to estimate the mixed and single associations between PM2.5 and early menopause.

RESULTS

The visibility topped the most important feature for derivations of historical PM2.5 concentrations. The R2 of 10-fold cross-validation and predictive capability during processing were all above 0.8. The prevalence of early menopause was 7.3 %. Each 10 µg/m3 PM2.5 increased the prevalence of early menopause during prior 2 years exposure (OR: 1.49, 95 %CI: 1.03-2.16) and spring and autumn (OR: 1.28, 95 %CI: 1.07-1.54). After adjusting the reverse effects of temperature, the prior 2 years exposure of PM2.5 remained positively associated with early menopause in the fourth quantile vs the first quantile (OR: 3.36, 95 %CI: 1.53-7.36) in the spring and autumn. The higher BMI (OR: 1.40, 95 %CI: 1.14-1.72), waistline (OR: 1.42, 95 %CI: 1.09-1.85) and unfavourable dietary habits of less meat (OR: 1.72, 95 %CI: 1.11-2.68), more fried food (OR: 2.39, 95 %CI: 1.15-4.99) elevated the prevalence of early menopause.

CONCLUSIONS

The accurate environmental exposure assessment of historical PM2.5 vigorously promoted the researches on the relationship between PM2.5 and early menopause. It sounds the alarm on female infertility menace associated with particulate matter especially during the turbulent 2 years before menopause.

Identification of endocrine-disrupting chemicals targeting key OP-associated genes via bioinformatics and machine learning

Osteoporosis (OP), a metabolic disorder predominantly impacting postmenopausal women, has seen considerable progress in diagnosis and treatment over the past few decades. However, the intricate interplay between genetic factors and endocrine disruptors (EDCs) in the pathogenesis of OP remains inadequately elucidated. The objective of this research is to examine the environmental pollutants and their regulatory mechanisms that could potentially influence the pathogenesis of OP, in order to establish a theoretical foundation for the targeted prevention and medical management of individuals with OP. Utilizing CTD and GEO datasets, network toxicology and bioinformatics analyses were conducted to identify target genes from a pool of 98 co-associated genes. Subsequently, a novel prediction model was developed employing a multiple machine learning algorithm. The efficacy of the model was validated based on the area under the receiver operating characteristic curve. Finally, real-time quantitative polymerase chain reaction (qRT-PCR) was used to confirm the expression levels of key genes in clinical samples. We have identified significant genes (FOXO3 and LUM) associated with OP and conducted Gene Ontology, Kyoto Encyclopedia of Genes and Genomes enrichment analysis, immune infiltration analysis, and molecular docking analysis. Through the analysis of these key genes, we have identified 13 EDCs that have the potential to impact OP. Several endocrine disruptors, such as Dexamethasone, Perfluorononanoic acid, genistein, cadmium, and bisphenol A, have been identified as notable environmental pollutants that impact the OP. Molecular docking analysis revealed significant binding affinity of major EDCs to the post-translational protein structures of key genes. This study demonstrates that EDCs, including dexamethasone, perfluorononanoic acid, genistein, cadmium, and bisphenol A, can be identified as important environmental pollutants affecting OP, and that FOXO3 and LUM have the potential to be diagnostic markers for OP. These results elucidate a novel association between EDCs regulated by key genes and the onset of OP.

PFAS and their association with the increased risk of cardiovascular disease in postmenopausal women

Cardiovascular diseases (CVDs) are one of the major causes of death globally. In addition to traditional risk factors such as unhealthy lifestyles (smoking, obesity, sedentary) and genetics, common environmental exposures, including persistent environmental contaminants, may also influence CVD risk. Per- and polyfluoroalkyl substances (PFASs) are a class of highly fluorinated chemicals used in household consumer and industrial products known to persist in our environment for years, causing health concerns that are now linked to endocrine disruptions and related outcomes in women, including interference of the cardiovascular and reproductive systems. In postmenopausal women, higher levels of PFAS are observed than in premenopausal women due to the cessation of menstruation, which is crucial for PFAS excretion. Because of these findings, we explored the association between perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and perfluorobutanesulfonic acid in postmenopausal women from our previously established CVD study. We used liquid chromatography with tandem mass spectrometry, supported by machine learning approaches, and the detection and quantification of serum metabolites and proteins. Here, we show that PFOS can be a good predictor of coronary artery disease, whereas PFOA can be an intermediate predictor of coronary microvascular disease. We also found that the PFAS levels in our study are significantly associated with inflammation-related proteins. Our findings may provide new insight into the potential mechanisms underlying the PFAS-induced risk of CVDs in this population. This study shows that exposure to PFOA and PFOS is associated with an increased risk of cardiovascular disease in postmenopausal women. PFOS and PFOA levels correlate with amino acids and proteins related to inflammation. These circulating biomarkers contribute to the etiology of CVD and potentially implicate a mechanistic relationship between PFAS exposure and increased risk of cardiovascular events in this population.

Phthalates and sex steroid hormones across the perimenopausal period: A longitudinal analysis of the Midlife Women's Health Study

BACKGROUND

The menopausal transition involves significant sex hormone changes. Environmental chemicals, such as urinary phthalate metabolites, are associated with sex hormone levels in cross-sectional studies. Few studies have assessed longitudinal associations between urinary phthalate metabolite concentrations and sex hormone levels during menopausal transition.

METHODS

Pre- and perimenopausal women from the Midlife Women's Health Study (MWHS) (n = 751) contributed data at up to 4 annual study visits. We quantified 9 individual urinary phthalate metabolites and 5 summary measures (e.g., phthalates in plastics (∑Plastic)), using pooled annual urine samples. We measured serum estradiol, testosterone, and progesterone collected at each study visit, unrelated to menstrual cycling. Linear mixed-effects models and hierarchical Bayesian kernel machine regression analyses evaluated adjusted associations between individual and phthalate mixtures with sex steroid hormones longitudinally.

RESULTS

We observed associations between increased concentrations of certain phthalate metabolites and lower testosterone and higher sub-ovulatory progesterone levels, e.g., doubling of monoethyl phthalate (MEP), monobenzyl phthalate (MBzP), di-2-ethylhexyl phthalate (∑DEHP) metabolites, ∑Plastic, and ∑Phthalates concentrations were associated with lower testosterone (e.g., for ∑DEHP: -4.51%; 95% CI: -6.72%, -2.26%). For each doubling of MEP, certain DEHP metabolites, and summary measures, we observed higher mean sub-ovulatory progesterone (e.g., ∑AA (metabolites with anti-androgenic activity): 6.88%; 95% CI: 1.94%, 12.1%). Higher levels of the overall time-varying phthalate mixture were associated with lower estradiol and higher progesterone levels, especially for 2nd year exposures.

CONCLUSIONS

Phthalates were longitudinally associated with sex hormone levels during the menopausal transition. Future research should assess such associations and potential health impacts during this understudied period.

Physical activity and menopausal symptoms: evaluating the contribution of obesity, fitness, and ambient air pollution status

OBJECTIVE

The menopausal transition is accompanied by transient symptoms that have been linked to subclinical cardiovascular disease (CVD); CVD has also been linked to air pollution. Physical activity (PA) reduces CVD, improves body composition, and can reduce menopausal symptoms. The purpose of this study was to assess the links between PA and menopausal symptoms and whether obesity, fitness, and air pollution status play a role in this relationship.

METHODS

Women (40-60 y; N = 243; mean [SD] age, 47.8 [5.6] y) from areas with high versus low air pollution enrolled in the Healthy Aging in Industrial Environment Program 4 prospective cohort study completed psychological, cardiorespiratory fitness, body composition, and menopausal status screening followed by a 14-day prospective assessment of menopausal symptoms (Menopause Rating Scale) using a mobile application. Daily PA was assessed objectively across 14 days via Fitbit Charge 3 monitor. General linear mixed models were conducted and controlled for age, menopausal status, day in the study, wear time, and neuroticism.

RESULTS

Peri/postmenopausal women ( β = 0.43, P < 0.001) and those residing in a high-air-pollution environment ( β = 0.45, P < 0.05) reported more somatovegetative symptoms. Hot flashes alone were associated with peri/postmenopausal status ( β = 0.45, P < 0.001), and for women residing in a high-air-pollution environment, lower reporting of hot flashes was observed on days when a woman was more physically active than usual ( β = -0.15, P < 0.001). No associations were found for cardiorespiratory fitness and visceral fat with any of the symptoms.

CONCLUSIONS

PA may enhance resilience to hot flashes, especially when residing in high-air-pollution environments where we also observed higher reporting of somatovegetative menopausal symptoms.

Proteomic analysis reveals that cigarette smoke exposure diminishes ovarian reserve in mice by disrupting the CREB1-mediated ovarian granulosa cell proliferation-apoptosis balance

Exposure to cigarette smoke (CS) adversely affects ovarian health and it is currently unknown how CS exposure causes ovarian injury. This study compared the differences in proteomics between CS exposure and healthy control groups using liquid chromatography-tandem mass spectrometry quantitative proteomics to further understand the molecular mechanism of ovarian cell injury in mice exposed to CS. Furthermore, western blotting and qPCR were carried out to validate the proteomic analysis outcomes. CREB1 was selected from the differentially expressed proteins, and then the down-regulation of CREB1 and phosphorylated CREB1(Ser133) expressions were confirmed in mice ovarian tissue and human ovarian granulosa cells (KGN cells) after CS exposure. In addition, the expressions of apoptosis-related proteins BCL-2 and BCL-XL were downregulated, and BAX expression was up-regulated. Moreover, the results of cellular immunofluorescence, flow cytometry, and transmission electron microscopy (TEM) showed that cigarette smoke extract (CSE) efficiently stimulated the production of reactive oxygen species, apoptosis, G1 phase arrest, mitochondrial membrane potential decreases, and ultrastructural changes in KGN cells. KG-501 (CREB inhibitor) aggravated CSE-induced mitochondrial dysfunction and apoptosis-proliferation imbalance in KGN cells mediated by down-regulated CREB1/BCL-2 axis. In addition, CREB1 over-expression partially restores mitochondrial dysfunction and apoptosis-proliferation imbalance of KGN cells induced by CSE. The results suggested that CSE diminished ovarian reserve in mice by disrupting the CREB1-mediated ovarian granulosa cell (GCs) proliferation-apoptosis balance and provided possible therapeutic targets for the clinical intervention of premature ovarian failure (POI) caused by CS exposure.

Drawing the Linkage Between Women's Reproductive Health, Climate Change, Natural Disaster, and Climate-driven Migration: Focusing on Low- and Middle-income Countries - A Systematic Overview

Background

One of the most important aspects of women's well-being and welfare is RSH (reproductive and sexual health). Reproductive health is not an exception to the threat that CCC (climate change and climate crisis) poses to numerous facets of public health. Firstly, the present review seeks to identify the influence of climatic changes, natural disasters, and climate-driven migration on RSH. Secondly, to identify knowledge gaps regarding the same.

Material and Methods

Two databases (Scopus and PubMed) were scanned using Boolean operation. The literature search aimed to find records pertaining to topics of RSH and climate change. Using the PRISMA-ScR method, records were screened and shortlisted based on established inclusion criteria. This literature search was carried out in November 2022. In the shortlisted records, preference for the comprehensive review articles was given.

Results

The present review is based on 38 records that collectively revealed that climate crisis and natural disasters have many negative impacts on female reproductive health. These effects are observed in different phases of life, ranging from teenage to menopause. The unique strength of the present review is that it draws a relationship between female reproductive health and the direct as well as indirect effects of the CCC. The available literature about LMICs is predominantly confined to drought, flood, and earthquake. Disasters like tsunamis, cyclones, and avalanches remain unexplored.

Conclusion

From the available literature, it is quite evident that CCC has an adverse effect on a woman's reproductive life as well as a bearing on future generations' health. Filling these knowledge gaps is pivotal for designing more effective disaster and health policies. Policymakers should take into consideration these detrimental effects while designing health schemes and policies for females.

Evaluating endocrine disrupting chemicals: A perspective on the novel assessments in CLARITY-BPA

BACKGROUND

The Consortium Linking Academic and Regulatory Insights on Bisphenol A Toxicity (CLARITY-BPA) was a collaborative research effort to better link academic research with governmental guideline studies. This review explores the secondary goal of CLARITY-BPA: to identify endpoints or technologies from CLARITY-BPA and prior/concurrent literature from these laboratories that may enhance the capacity of rodent toxicity studies to detect endocrine disrupting chemicals (EDCs).

METHODS

A systematic literature search was conducted with search terms for BPA and the CLARITY-BPA participants. Relevant studies employed a laboratory rodent model and reported results on 1 of the 10 organs/organ systems evaluated in CLARITY-BPA (brain and behavior, cardiac, immune, mammary gland, ovary, penile function, prostate gland and urethra, testis and epididymis, thyroid hormone and metabolism, and uterus). Study design and findings were summarized, and a risk-of-bias assessment was conducted.

RESULTS

Several endpoints and methods were identified as potentially helpful to detect effects of EDCs. For example, molecular and quantitative morphological approaches were sensitive in detecting alterations in early postnatal development of the brain, ovary, and mammary glands. Hormone challenge studies mimicking human aging reported increased susceptibility of the prostate to disease following developmental BPA exposure. Statistical analyses for nonmonotonic dose responses, and computational approaches assessing multiple treatment-related outcomes concurrently in linked hormone-sensitive organ systems, reported effects at low BPA doses.

CONCLUSIONS

This review provided an opportunity to evaluate the unique insights provided by nontraditional assessments in CLARITY-BPA to identify technologies and endpoints to enhance detection of EDCs in future studies.

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.

Comparison of the effects of six-week time-restricted eating on weight loss, body composition, and visceral fat in overweight older men and women

The aim of this study was to determine the effectiveness of a six-week time-restricted eating (TRE) intervention in reducing body weight, fat loss, and visceral fat in overweight, older adult men and women (age range = 65-74 years). Another objective was to determine the feasibility of widespread use of TRE in older women and men. The study randomly assigned 116 healthy, non-smoking participants to one of two conditions: TRE or educational control participants. Participants in the TRE group were instructed to not consume calorie containing beverages or food for 16 h per day, from 8:00 pm to 12:00 pm. Participants in the control group were instructed to follow a meal plan based on their previous habits. The changes in body weight and body composition were determined using a SECA mBCA 515 analyzer. The six-week TRE intervention resulted in a significant decrease in body weight in both men and women (-1.8 kg and-1.3 kg, respectively; p = 0.03). In men, a significant decrease in visceral fat mass (-0.54 l; p ≤ 0.001) and waist circumference (-2.9 cm; p ≤ 0.015) was observed. No significant changes in either visceral fat or waist circumference were observed in women. Additionally, no change in skeletal muscle mass was observed in either the control or TRE group. More than 99 % of female and 98 % of male participants were able to adhere to the prescribed time-restricted eating (16/8) plan, suggesting that this dietary approach could have beneficial effects on the body composition of overweight older men and may also reduce body weight in overweight, older women.

Ovarian volume partially explains associations of phthalate biomarkers with anti-Müllerian hormone and estradiol in midlife women

BACKGROUND/OBJECTIVES

Women are ubiquitously exposed to endocrine disruptors, including phthalates. Ovarian follicles undergoing folliculogenesis (indirectly measured by ovarian volume) produce anti-Müllerian hormone (AMH) and estradiol (E2). We evaluated associations of phthalates with ovarian volume to assess whether this explained prior positive associations of phthalates with AMH and E2.

METHODS

Women ages 45-54 years (n = 614) had transvaginal ultrasounds of right/left ovaries to calculate mean ovarian volume. Women provided up-to-four urine and blood samples for quantifying AMH (first serum sample), E2 (all serum samples), and nine phthalate metabolites (from pooled urine, representing six parent phthalates). Multivariable linear or logistic regression models (for individual phthalate biomarkers), as well as weighted quantile sum (WQS) regression (for mixture analyses) evaluated associations of phthalate biomarkers with ovarian volume. Using cross-sectional mediation analysis, we assessed whether associations of phthalates with ovarian volume partially explained those of phthalates with AMH or E2.

RESULTS

Most women were non-Hispanic White (68%) and pre-menopausal (67%) with higher urinary phthalate metabolite concentrations than U.S. women. In single-pollutant models, 10% increases in mono(3-carboxypropyl) phthalate (MCPP) and monobenzyl phthalate (MBzP) were associated with 0.44% (95% CI: -0.02%, 0.91%) and 0.62% (95% CI: 0.02%, 1.23%) larger ovarian volumes, respectively. As a cumulative mixture, 10% increases in the phthalate mixture were associated with 2.89% larger ovarian volume (95%CI: 0.27, 5.59) with MCPP (35%) and MBzP (41%) identified as major contributors. Higher ovarian volume due to a 10% increase in MBzP (indirect effect OR: 1.004; 95% CI: 1.00, 1.01) explained 16% of the positive association between MBzP and higher AMH, whereas higher ovarian volume due to a 10% increase in MCPP (indirect effect %Δ: 0.11; 95% CI: -0.01, 0.22) explained 23% of the positive association between MCPP and E2.

CONCLUSION

In this cross-sectional study, phthalates were associated with increased ovarian volume, with implications for midlife hormone production.

Carbon tetrachloride exposure induces ovarian damage through oxidative stress and inflammatory mediated ovarian fibrosis

Carbon tetrachloride (CCL₄) is widely used as a chemical intermediate and as a feedstock in the production of chlorofluorocarbons. CCL₄ is highly toxic in the liver, kidney, testicle, brain and other tissues. However, the effect of CCL₄ on ovarian function has not been reported. In this study, we found that the mice treated with CCL₄ showed decreased ovarian function with disturbed estrus cycle, decreased serum level of 17β-estradiol and the reduced number of healthy follicles. Ovarian damage was accompanied by oxidative stress and the production of proinflammatory cytokines, especially interleukins. The indicators of oxidative stress, 4-Hydroxynonenal (4-HNE), 8-hydroxy-2´-deoxyguanosine (8-OHdG), 3-Nitrotyrosine (3-NT) and malondialdehyde (MDA), and the levels of proinflammatory cytokines IL-1α, IL-1β, IL-6 and IL-11 were increased, while the antioxidants, including superoxide dismutase (SOD), nuclear factor erythroid2-related factor 2 (NRF2) and heme oxygenase-1 (HO-1), were decreased in the CCL₄ group. In the CCL₄ treated group, the results of Sirius Red staining, immunohistochemistry and qPCR indicated that proinflammatory cytokines caused further ovarian fibrosis. And CCL₄ could also promote ovarian thecal cells to secrete inflammatory cytokines, resulting in fibrosis in vitro. In addition, CCL₄ inhibited oocyte development and triggered oocyte apoptosis. In conclusion, CCL₄ exposure causes ovarian damage by strong oxidative stress and the high expression of the proinflammatory cytokine mediated ovarian fibrosis.

Risk of Depression during Menopause in Women from Poland, Belarus, Belgium, and Greece

Introduction: Menopause is a physiological period in a woman’s life, but it is often accompanied by symptoms that affect mental well-being and general health, including a tendency for depression. Aim of the study: To evaluate the predisposition to the symptoms of depression in women from Poland, Belarus, Belgium, and Greece. Material and methods: the method of diagnostic survey was used, and the research tools were: The Menopause Rating Scale, the Kupperman Index, Beck Depression Inventory, and a self-made survey questionnaire. Results: Hormone replacement therapy (HRT) was used by 15.8% of Polish, 19% of Belgian, 14.3% of Belarusian, and 15.2% of Greek women patients. The mean value of the Kupperman Index (range 0–63) in Poland was 14.8 ± 8.6, in Belgium—15.5 ± 6.6, Belarus—14.0 ± 9.4, and Greece—10.8 ± 6.5, while the total measure of Menopause Rating Scale (MRS) (range 0–44) was 12.2 ± 7.6 in Poland, 13.8 ± 6.5 in Belgium, 10.8 ± 8.0 in Belarus and 12.9 ± 7.4 in Greece. The severity of mental distress followed a similar pattern across all countries (slightly stronger than mild). The results for somatic complaints were similar, whereas the level of sexual issues varied, with the highest in Belgium and the lowest in Belarus. The mildest symptoms of menopause were experienced by Belarusian women and the most severe by Belgian women. The severity of depression, according to the Beck Depression Inventory (range 0–63), was as follows: Poland 10.5 ± 7.9; Belgium—11.1 ± 5.7; Belarus—13.7 ± 5.7; Greece—11.8 ± 6.6. Conclusions: The differences between the development of perimenopausal-related symptoms across countries were statistically significant. The incidence and severity of depression showed statistically significant differences between the countries studied—the highest was in Belarus and the lowest in Poland. Depression levels were not differentiated by subjects’ age or the use of hormone therapy but by subjects’ education. In Poland and Belarus, increased menopausal pain measured by the Kupperman Index altered levels of depression; in Belgium, there were no such correlations, and in Greece, the correlation was statistically significant, but its strength was negligible. A clearer correlation of the effects of development in menopausal symptoms on the level of depression was shown when measured with the MRS scale—in Greece and Belgium, the correlation was relatively weak, but in Poland and Belarus, it was relatively high.