The influence of environmental factors on premature ovarian insufficiency and ovarian aging

PFAS and menopause onset: Is it just a matter of reverse causation? Cross-sectional and longitudinal analyses in highly exposed women in the Veneto Region

INTRODUCTION

Several cross-sectional studies have linked perfluoroalkyl substances (PFAS) to prevalence of menopause. These findings might be influenced by reverse causation mechanism, making longitudinal studies more suitable. However, existing longitudinal studies are limited and present conflicting results.

AIM

This study investigates the association between PFAS and both prevalence and incidence of menopause, using longitudinal designs to limit the impact of reverse causation.

METHODS

A surveillance program on a PFAS highly exposed population in the Veneto region started in 2017 with two rounds of screening, on average 3.8 years apart. Women who participated in the first screening (n = 11,046) were included in the cross-sectional analysis. Multivariate logistic regression models were used to estimate the Odds Ratios (ORs) of menopause associated with exposure to different PFAS. For incidence analysis a retrospective-prospective design used PFOA concentrations reconstructed to 2013 (n = 8536), and a prospective design involved women participating in both screenings (n = 1709), evaluating their baseline concentrations of PFOA, PFOS, and PFHxS. Cox proportional hazards models with age as the timescale were used to estimate Hazard Ratios (HRs), adjusting for sociodemographic and lifestyle factors.

RESULTS

Increased menopause prevalence was associated with higher ln-concentrations of PFOA, PFOS, and PFHxS, with ORs of 1.31 (CI: 1.25-1.38), 1.51 (CI: 1.38-1.66), and 1.42 (CI: 1.34-1.51), respectively. The retrospective-prospective study showed increased risk of menopause in higher PFOA reconstructed quartiles, with HRs of 1.01 (CI: 0.87-1.18), 1.17 (CI: 1.02-1.37), and 1.07 (CI: 0.93-1.23) for the second, third and fourth quartiles. The prospective longitudinal study found no association between PFAS and menopause onset.

CONCLUSIONS

Our results showed a strong cross-sectional association between PFAS exposure and menopause, a weak positive association in the retrospective-prospective study, and no association in the prospective study. This suggests that cross-sectional associations may largely result from reverse causality due to early menopause on reducing PFAS excretion.

Metabolome-wide Mendelian randomization assessing the causal relationship between blood metabolites and primary ovarian insufficiency

BACKGROUND & AIMS

Primary ovarian insufficiency (POI) is a significant clinical syndrome that leads to female infertility, and its incidence continues to increase. We used metabolome-specific Mendelian randomization (MR) to identify causally associated metabolites and explore the relationship between candidate metabolites and upstream genetic variations.

METHODS

The primary MR analysis utilized the inverse variance weighted (IVW) method as the primary approach to assess the causal relationship between exposure and POI. Multiple sensitivity analyses included MR-Egger, weighted median, and weighted mode methods.

RESULTS

After using genetic variants as probes, we identified 27 metabolites of 278 that are associated with the risk of POI, including dodecanedioate (OR 0.052, 95 % CI 0.010-0.265; P < 0.001), adrenate (OR 0.113, 95 % CI 0.016-0.822; P = 0.031), indolepropionate (OR 0.174, 95 % CI 0.051-0.593; P = 0.005), homocitrulline (OR 0.194, 95 % CI 0.051-0.741; P = 0.016), and 3-methylhistidine (OR 0.404, 95 % CI 0.193-0.848; P = 0.017). Our study indicated the presence of heterogeneity; therefore, we employed the IVW random-effects model as the primary approach. KEGG pathway enrichment analysis identified six significant metabolic pathways, primarily including biosynthesis of unsaturated fatty acids, phenylalanine, tyrosine and tryptophan biosynthesis, aminoacyl-tRNA biosynthesis, linoleic acid metabolism, valine, leucine and isoleucine biosynthesis, ubiquinone and other terpenoid-quinone biosynthesis.

CONCLUSIONS

By integrating genomics and metabolomics, this study provides novel insights into the causal relationship linking circulating metabolites and the onset of POI.

Factors affecting age at menopause and their relationship with ovarian reserve: a comprehensive review

OBJECTIVE

The aim of this article was to discuss all the factors affecting the age at menopause and their correlation with ovarian reserve.

MATERIALS AND METHODS

A narrative review of original articles was performed using PubMed until December 2023. The following keywords were used to generate the list of citations: 'menopause', 'ovarian reserve' 'oocytes quality and quantity', 'ovarian ageing'.

RESULTS

Menopause is the final step in the process of ovarian ageing and is influenced by the oocyte pool at birth. Conditions that accelerate follicle depletion during the reproductive lifespan lead to premature ovarian insufficiency (POI) and premature ovarian failure (POF), while a higher ovarian reserve is associated with a delayed time to menopause. Reproductive history, sociodemographic, lifestyle and iatrogenic factors may impact ovarian reserve and the age at menopause.

CONCLUSIONS

Some factors affecting the age at menopause are modifiable and the risks of early menopause may be preventable. We hypothesise that by addressing these modifiable factors we may also preserve ovarian reserve. However, further interventional studies are needed to evaluate the effects of the described strategies on ovarian reserve.

Premature ovarian insufficiency

Premature ovarian insufficiency (POI) is a cause of infertility and endocrine dysfunction in women, defined by loss of normal, predictable ovarian activity before the age of 40 years. POI is clinically characterized by amenorrhoea (primary or secondary) with raised circulating levels of follicle-stimulating hormone. This condition can occur due to medical interventions such as ovarian surgery or cytotoxic cancer therapy, metabolic and lysosomal storage diseases, infections, chromosomal anomalies and autoimmune diseases. At least 1 in 100 women is affected by POI, including 1 in 1,000 before the age of 30 years. Substantial evidence suggests a genetic basis to POI. However, the cause of idiopathic POI remains unknown in most patients, indicating that gene variants associated with this condition remain to be discovered. Over the past 10 years, tremendous progress has been made in our knowledge of genes involved in POI. Genetic approaches in diagnosis are important as they enable patients with familial POI to be identified, with the opportunity for oocyte preservation. Moreover, genetic approaches could provide a better understanding of disease mechanisms, which will ultimately aid the development of improved treatments.

[Climate and environmental crisis impacts on women's health: What specificities? What can be done?]

OBJECTIVE

Pollution is one of the world's largest risk factors for disease and premature death. In Europe, it is responsible for approximately 20% of mortality. Chemicals exposure can occur by inhalation, ingestion or skin contact and begins in utero. Pollutants can be divided into three categories: endocrine disruptors (pesticides, PFAS, plastics, dioxins, etc.), heavy metals (cadmium, mercury and lead…) and nanomaterials. Climate change and air pollution are other main health threats.

METHODS

Literature review using PubMed and ResearchGate databases and institutional websites.

RESULTS

Endocrine disruptors are identified as significant risk factors for the reproductive health with negative documented impacts following prenatal or adult exposure. Climate change and air pollution can cause gender-based health disparities. Numerous scientific arguments show that chemical pollution and climate change disproportionately impact women, both on a social and biological level. Populations in precarious situations among which women are over-represented suffer the most severe social consequences including in France. There are several gender-specific domestic or occupational exposures to pollutants, most often to the disadvantage of women compared to men. Finally, although very few gendered data exist in environmental health, there are sexual-based physiological vulnerabilities concerning the metabolism of pollutants and the capacity to adapt to heat.

CONCLUSION

Facing this threat of gender inequity in sexual and reproductive health and rights' width, women's health professionals have a major role to play in initiating new ways to assess and reduce the environmental health burden in women.

Current Status and Future Prospects of Stem Cell Therapy for Infertile Patients with Premature Ovarian Insufficiency

Premature ovarian insufficiency (POI), also known as premature menopause or premature ovarian failure, signifies the partial or complete loss of ovarian endocrine function and fertility before 40 years of age. This condition affects approximately 1% of women of childbearing age. Although 5-10% of patients may conceive naturally, conventional infertility treatments, including assisted reproductive technology, often prove ineffective for the majority. For infertile patients with POI, oocyte donation or adoption exist, although a prevalent desire persists among them to have biological children. Stem cells, which are characterized by their undifferentiated nature, self-renewal capability, and potential to differentiate into various cell types, have emerged as promising avenues for treating POI. Stem cell therapy can potentially reverse the diminished ovarian endocrine function and restore fertility. Beyond direct POI therapy, stem cells show promise in supplementary applications such as ovarian tissue cryopreservation and tissue engineering. However, technological and ethical challenges hinder the widespread clinical application of stem cells. This review examines the current landscape of stem cell therapy for POI, underscoring the importance of comprehensive assessments that acknowledge the diversity of cell types and functions. Additionally, this review scrutinizes the limitations and prospects associated with the clinical implementation of stem cell treatments for POI.