Events in Early Life are Associated with Female Reproductive Ageing: A UK Biobank Study

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.

Understanding the genetic complexity of puberty timing across the allele frequency spectrum

Pubertal timing varies considerably and is associated with later health outcomes. We performed multi-ancestry genetic analyses on ~800,000 women, identifying 1,080 signals for age at menarche. Collectively, these explained 11% of trait variance in an independent sample. Women at the top and bottom 1% of polygenic risk exhibited ~11 and ~14-fold higher risks of delayed and precocious puberty, respectively. We identified several genes harboring rare loss-of-function variants in ~200,000 women, including variants in ZNF483, which abolished the impact of polygenic risk. Variant-to-gene mapping approaches and mouse gonadotropin-releasing hormone neuron RNA sequencing implicated 665 genes, including an uncharacterized G-protein-coupled receptor, GPR83, which amplified the signaling of MC3R, a key nutritional sensor. Shared signals with menopause timing at genes involved in DNA damage response suggest that the ovarian reserve might signal centrally to trigger puberty. We also highlight body size-dependent and independent mechanisms that potentially link reproductive timing to later life disease.

Age at natural menopause and its determinants in female population of Kharameh cohort study: Comparison of regression, conditional tree and forests

BACKGROUND

Natural menopause is defined as the permanent cessation of menstruation that occurs after 12 consecutive months of amenorrhea without any obvious pathological or physiological cause. The age of this phenomenon has been reported to be associated with several health outcomes.

OBJECTIVES

This study aimed to estimate the Age at Natural Menopause (ANM) and to identify reproductive and demographic factors affecting ANM.

METHODS

This cross-sectional, population-based study was conducted on 2517 post-menopausal women aged 40-70 years participating in the first phase of the PERSIAN cohort study of Kharameh, Iran, during 2014-2017. To more accurately detect the determinants of ANM, we applied multiple linear regression beside some machine learning algorithms including conditional tree, conditional forest, and random forest. Then, the fitness of these methods was compared using Mean Squared Error (MSE) and Pearson correlation coefficient.

RESULTS

The mean±SD of ANM was 48.95±6.13. Both applied forests provided more accurate results and identified more predictors. However, according to the final comparison, the conditional forest was the most accurate method which recognized that more pregnancies, longer breastfeeding, Fars ethnicity, and urbanization have the greatest impact on later ANM.

CONCLUSIONS

This study found a wide range of reproductive and demographic factors affecting ANM. Considering our findings in decision-making can reduce the complications related to this phenomenon and, consequently, improve the quality of life of post-menopausal women.

Establishing the relationships between adiposity and reproductive factors: a multivariable Mendelian randomization analysis

BACKGROUND

Few studies have investigated associations between adiposity and reproductive factors using causal methods, both of which have a number of consequences on women's health. Here we assess whether adiposity at different points in the lifecourse affects reproductive factors differently and independently, and the plausibility of the impact of reproductive factors on adiposity.

METHODS

We used genetic data from UK Biobank (273,238 women) and other consortia (EGG, GIANT, ReproGen and SSGAC) for eight reproductive factors: age at menarche, age at menopause, age at first birth, age at last birth, number of births, being parous, age first had sexual intercourse and lifetime number of sexual partners, and two adiposity traits: childhood and adulthood body size. We applied multivariable Mendelian randomization to account for genetic correlation and to estimate the causal effects of childhood and adulthood adiposity, independently of each other, on reproductive factors. Additionally, we estimated the effects of reproductive factors, independently of other relevant reproductive factors, on adulthood adiposity.

RESULTS

We found a higher childhood body size leads to an earlier age at menarche, and an earlier age at menarche leads to a higher adulthood body size. Furthermore, we find contrasting and independent effects of childhood and adulthood body size on age at first birth (beta 0.22 SD (95% confidence interval: 0.14, 0.31) vs - 2.49 (- 2.93, - 2.06) per 1 SD increase), age at last birth (0.13 (0.06,0.21) vs - 1.86 (- 2.23, - 1.48) per 1 SD increase), age at menopause (0.17 (0.09, 0.25) vs - 0.99 (- 1.39, - 0.59) per 1 SD increase), and likelihood of having children (Odds ratio 0.97 (0.95, 1.00) vs 1.20 (1.06, 1.37) per 1 SD increase).

CONCLUSIONS

Our findings demonstrate the importance of considering a lifecourse approach when investigating the inter-relationships between adiposity measures and reproductive events, as well as the use of 'age specific' genetic instruments when evaluating lifecourse hypotheses in a Mendelian randomization framework.

Review of mendelian randomization studies on age at natural menopause

Menopause marks the end of the reproductive phase of life. Based on epidemiological studies, abnormal age at natural menopause (ANM) is thought to contribute to a number of adverse outcomes, such as osteoporosis, cardiovascular disease, and cancer. However, the causality of these associations remains unclear. A powerful epidemiological method known as Mendelian randomization (MR) can be used to clarify the causality between ANM and other diseases or traits. The present review describes MR studies that included ANM as an exposure, outcome and mediator. The findings of MR analyses on ANM have revealed that higher body mass index, poor educational level, early age at menarche, early age at first live birth, early age at first sexual intercourse, and autoimmune thyroid disease appear to be involved in early ANM etiology. The etiology of late ANM appears to be influenced by higher free thyroxine 4 and methylene tetrahydrofolate reductase gene mutations. Furthermore, early ANM has been found to be causally associated with an increased risk of osteoporosis, fracture, type 2 diabetes mellitus, glycosylated hemoglobin, and the homeostasis model of insulin resistance level. In addition, late ANM has been found to be causally associated with an increased systolic blood pressure, higher risk of breast cancer, endometrial cancer, endometrioid ovarian carcinoma, lung cancer, longevity, airflow obstruction, and lower risk of Parkinson's disease. ANM is also a mediator for breast cancer caused by birth weight and childhood body size. However, due to the different instrumental variables used, some results of studies are inconsistent. Future studies with more valid genetic variants are needed for traits with discrepancies between MRs or between MR and other types of epidemiological studies.

Understanding the genetic complexity of puberty timing across the allele frequency spectrum

Pubertal timing varies considerably and has been associated with a range of health outcomes in later life. To elucidate the underlying biological mechanisms, we performed multi-ancestry genetic analyses in ~800,000 women, identifying 1,080 independent signals associated with age at menarche. Collectively these loci explained 11% of the trait variance in an independent sample, with women at the top and bottom 1% of polygenic risk exhibiting a ~11 and ~14-fold higher risk of delayed and precocious pubertal development, respectively. These common variant analyses were supported by exome sequence analysis of ~220,000 women, identifying several genes, including rare loss of function variants in ZNF483 which abolished the impact of polygenic risk. Next, we implicated 660 genes in pubertal development using a combination of in silico variant-to-gene mapping approaches and integration with dynamic gene expression data from mouse embryonic GnRH neurons. This included an uncharacterized G-protein coupled receptor GPR83, which we demonstrate amplifies signaling of MC3R, a key sensor of nutritional status. Finally, we identified several genes, including ovary-expressed genes involved in DNA damage response that co-localize with signals associated with menopause timing, leading us to hypothesize that the ovarian reserve might signal centrally to trigger puberty. Collectively these findings extend our understanding of the biological complexity of puberty timing and highlight body size dependent and independent mechanisms that potentially link reproductive timing to later life disease.

Risk factors for natural menopause before the age of 45: evidence from two British population-based birth cohort studies

Background

Menopause that occurs before the age of 45 and is not medically induced (referred to here as ‘early natural menopause’) affects around one in 10 women and has serious health consequences. These consequences include increased risk of all-cause mortality, cardiovascular disease, osteoporosis, and type 2 diabetes.

Methods

We investigate risk factors for the onset of natural menopause before the age of 45 in two population-based prospective cohort studies in Britain: the 1958 cohort following 8959 women and the 1970 cohort following 8655 women. These studies follow women from birth to adulthood, and we use harmonized data on birth and early life characteristics, reproductive health, health behaviour, and socioeconomic characteristics for 6805 women who were pre-menopausal, peri-menopausal or had undergone natural menopause. Of these 6805 women, 3614 participated in the 1958 cohort (of which 368 had early menopause) and 3191 participated in the 1970 cohort (of which 206 had early menopause). Taking a life course approach, we focus on three distinct life stages - birth/early life, childhood, and early adulthood - to understand when risk factors are most harmful. Respecting the temporal sequence of exposures, we use a series of multivariable logistic regression models to estimate associations between early menopause and each potential risk factor adjusted for confounders.

Results

We find that early menopause is influenced by circumstances at birth. Women born in lower social class families, whose mother smoked during the pregnancy or who were breastfed 1 month or less were more likely to undergo early menopause. Early menopause is also associated with poorer cognitive ability and smoking in childhood. Adult health behaviour also matters. Smoking is positively correlated with early menopause, while regular exercise and moderate frequency of alcohol drinking in women’s early thirties are associated with reduced risk of early menopause. The occurrence of gynaecological problems by women’s early thirties is also linked to early menopause.

Conclusions

We demonstrate that characteristics at different periods of life are associated with early menopause. Some of these associations relate to modifiable behaviours and thus the risks of early menopause and the adverse health outcomes associated with it may be preventable.

Implementation of a comprehensive fertility biobanking initiative

OBJECTIVE

To present the framework of Stanford Fertility and Reproductive Health's comprehensive reproductive biobanking initiatives and the results of the first year of recruitment.

DESIGN

Technical description article.

SETTING

Academic fertility center.

PATIENT(S)

Fertility patients >18 years of age.

INTERVENTION(S)

Enroll the patients interested in research in biobanking protocols.

MAIN OUTCOME MEASURE(S)

Patient recruitment and sample inventory from September 2020 to September 2021.

RESULT(S)

A total of 253 patients have enrolled in the Stanford Fertility and Reproductive Health biobanking initiatives since September 2020. The current inventory consists of 1,176 samples, including serums, plasmas, buffy coats, endometria, maternal deciduae, miscarriage chorionic villi, and human embryos (zygote, cleavage, and blastocyst stages).

CONCLUSION(S)

This biobanking initiative addresses a critical, unmet need in reproductive health research to make it possible for patients to donate excess embryos and gametes and preserves, for future research, valuable somatic and reproductive tissues that would otherwise be discarded. We present the framework of this biobanking initiative in order to support future efforts of establishing similar biorepositories.

Premature menopause and autoimmune primary ovarian insufficiency in two international multi-center cohorts

Objective

To investigate markers of premature menopause (<40 years) and specifically the prevalence of autoimmune primary ovarian insufficiency (POI) in European women.

Design

Postmenopausal women were categorized according to age at menopause and self-reported reason for menopause in a cross-sectional analysis of 6870 women.

Methods

Variables associated with the timing of menopause and hormone measurements of 17β-estradiol and follicle-stimulating hormone were explored using multivariable logistic regression analysis. Specific immunoprecipitating assays of steroidogenic autoantibodies against 21-hydroxylase (21-OH), side-chain cleavage enzyme (anti-SCC) and 17alpha-hydroxylase (17 OH), as well as NACHT leucine-rich-repeat protein 5 were used to identify women with likely autoimmune POI.

Results

Premature menopause was identified in 2.8% of women, and these women had higher frequencies of nulliparity (37.4% vs 19.7%), obesity (28.7% vs 21.4%), osteoporosis (17.1% vs 11.6%), hormone replacement therapy (59.1% vs 36.9%) and never smokers (60.1% vs 50.9%) (P < 0.05), compared to women with menopause ≥40 years. Iatrogenic causes were found in 91 (47%) and non-ovarian causes in 27 (14%) women, while 77 (39%) women were classified as POI of unknown cause, resulting in a 1.1% prevalence of idiopathic POI. After adjustments nulliparity was the only variable significantly associated with POI (odds ratio 2.46; 95% CI 1.63-3.42). Based on the presence of autoantibodies against 21 OH and SCC, 4.5% of POI cases were of likely autoimmune origin.

Conclusion

Idiopathic POI affects 1.1% of all women and almost half of the women with premature menopause. Autoimmunity explains 4.5% of these cases judged by positive steroidogenic autoantibodies.

Bovine models for human ovarian diseases

During early embryonic development, late fetal growth, puberty, adult reproductive years, and advanced aging, bovine and human ovaries closely share molecular pathways and hormonal signaling mechanisms. Other similarities between these species include the size of ovaries, length of gestation, ovarian follicular and luteal dynamics, and pathophysiology of ovarian diseases. As an economically important agriculture species, cattle are a foundational species in fertility research with decades of groundwork using physiologic, genetic, and therapeutic experimental techniques. Many technologies used in modern reproductive medicine, such as ovulation induction using hormonal therapy, were first used in cows before human trials. Human ovarian diseases with naturally occurring bovine correlates include premature ovary insufficiency (POI), polycystic ovarian syndrome (PCOS), and sex-cord stromal tumors (SCSTs). This article presents an overview of bovine ovary research related to causes of infertility, ovarian diseases, diagnostics, and therapeutics, emphasizing where the bovine model can offer advantages over other lab animals for translational applications.

Association of In Utero Exposures With Risk of Early Natural Menopause

Suboptimal pregnancy conditions may affect ovarian development in the fetus and be associated with early natural menopause (ENM) for offspring. A total of 106,633 premenopausal participants in Nurses' Health Study II who provided data on their own prenatal characteristics, including diethylstilbestrol (DES) exposure, maternal cigarette smoking exposure, multiplicity, prematurity, and birth weight, were followed from 1989 to 2017. Cox regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations of in utero exposures with ENM. During 1.6 million person-years of follow-up, 2,579 participants experienced ENM. In multivariable models, women with prenatal DES exposure had higher risk of ENM compared with those without it (HR = 1.33, 95% CI: 1.06, 1.67). Increased risk of ENM was observed for those with low (<5.5 pounds (<2.5 kg)) versus normal (7.0-8.4 pounds (3.2-3.8 kg)) birth weight (HR = 1.21, 95% CI: 1.01, 1.45). Decreasing risk was observed per 1-pound (0.45-kg) increase in birth weight (HR = 0.93, 95% CI: 0.90, 0.97). Prenatal smoking exposure, being part of a multiple birth, and prematurity were not associated with ENM. In this large cohort study, lower birth weight and prenatal DES exposure were associated with higher risk of ENM. Our results support a need for future research to examine in utero exposures that may affect offspring reproductive health.

The relationships between women's reproductive factors: a Mendelian randomisation analysis

BACKGROUND

Women's reproductive factors include their age at menarche and menopause, the age at which they start and stop having children and the number of children they have. Studies that have linked these factors with disease risk have largely investigated individual reproductive factors and have not considered the genetic correlation and total interplay that may occur between them. This study aimed to investigate the nature of the relationships between eight female reproductive factors.

METHODS

We used data from the UK Biobank and genetic consortia with data available for the following reproductive factors: age at menarche, age at menopause, age at first birth, age at last birth, number of births, being parous, age first had sexual intercourse and lifetime number of sexual partners. Linkage disequilibrium score regression (LDSC) was performed to investigate the genetic correlation between reproductive factors. We then applied Mendelian randomisation (MR) methods to estimate the causal relationships between these factors. Sensitivity analyses were used to investigate directionality of the effects, test for evidence of pleiotropy and account for sample overlap.

RESULTS

LDSC indicated that most reproductive factors are genetically correlated (rg range: |0.06-0.94|), though there was little evidence for genetic correlations between lifetime number of sexual partners and age at last birth, number of births and ever being parous (rg < 0.01). MR revealed potential causal relationships between many reproductive factors, including later age at menarche (1 SD increase) leading to a later age at first sexual intercourse (beta (B) = 0.09 SD, 95% confidence intervals (CI) = 0.06,0.11), age at first birth (B = 0.07 SD, CI = 0.04,0.10), age at last birth (B = 0.06 SD, CI = 0.04,0.09) and age at menopause (B = 0.06 SD, CI = 0.03,0.10). Later age at first birth was found to lead to a later age at menopause (B = 0.21 SD, CI = 0.13,0.29), age at last birth (B = 0.72 SD, CI = 0.67, 0.77) and a lower number of births (B = -0.38 SD, CI = -0.44, -0.32).

CONCLUSION

This study presents evidence that women's reproductive factors are genetically correlated and causally related. Future studies examining the health sequelae of reproductive factors should consider a woman's entire reproductive history, including the causal interplay between reproductive factors.

Age at menopause among rural and urban women in the state of Campeche, Mexico

OBJECTIVE

The purpose of this study was to examine age at natural menopause among women of Maya and non-Maya ancestry living in urban and rural communities in the state of Campeche, Mexico.

METHODS

Women ages 40 to 60 (n = 543) participated in semi-structured interviews and anthropometric measures. The last names, languages spoken, and the birthplace of the woman, her parents, and her grandparents were used to determine Maya or non-Maya ethnicity. Recalled age at natural menopause was compared across four communities; analysis of variance was used to compare means and Kaplan-Meier analyses were used to compare medians. Probit analysis was also used to estimate median ages at menopause. Cox regression analyses were applied to identify variables associated with age at menopause.

RESULTS

Mean recalled age at natural menopause across all sites was 46.7 years, ranging from 47.8 years in the city of Campeche to 43.9 years in the rural Maya communities in the municipality of Hopelchén. Median ages at menopause across all sites were 50.55 years by probit analysis and 50.5 years by Kaplan-Meier. Variables associated with a later age at menopause included higher socioeconomic status, higher parity, and a later age at menarche.

CONCLUSIONS

The early mean recalled age at menopause in southern Hopelchén was consistent with previous studies in the Yucatán peninsula. As expected, probit and Kaplan-Meier analyses demonstrated later ages at menopause. Contrary to our expectations, Maya/non-Maya ethnicity was not associated with age at menopause. Demographic and reproductive factors were more important than ethnicity in explaining variation in age at menopause within the state of Campeche, Mexico.

Increased Menopausal Age Reduces the Risk of Parkinson's Disease: A Mendelian Randomization Approach

BACKGROUND

Studies of Parkinson's disease (PD) and the association with age at menarche or menopause have reported inconsistent findings. Mendelian randomization (MR) may address measurement errors because of difficulties accurately reporting the age these life events occur.

OBJECTIVE

We used MR to assess the association between age at menopause and age at menarche with PD risk.

METHODS

We performed inverse variant-weighted (IVW) MR analysis using external genome-wide association study (GWAS) summary data from the United Kingdom biobank, and the effect estimates between genetic variants and PD among two population-based studies (Parkinson's disease in Denmark (PASIDA) study, Denmark, and Parkinson's Environment and Gene study [PEG], United States) that enrolled 1737 female and 2430 male subjects of European ancestry. We, then, replicated our findings for age at menopause using summary statistics from the PD consortium (19 773 women), followed by a meta-analysis combining all summary statistics.

RESULTS

For each year increase in age at menopause, the risk for PD decreased (odds ration [OR], 0.84; 95% confidence interval [CI], 0.73-0.98; P = 0.03) among women in our study, whereas there was no association among men (OR, 0.98; 95% CI, 0.85-1.11; P = 0.71). A replication using summary statistics from the PD consortium estimated an OR of 0.94 (95% CI, 0.90-0.99; P = 0.01), and we calculated a meta-analytic OR of 0.93 (95% CI, 0.89-0.98; P = 0.003). There was no indication for an association between age at menarche and PD (OR, 0.75; 95% CI, 0.44-1.29; P = 0.29).

CONCLUSIONS

A later age at menopause was associated with a decreased risk of PD in women, supporting the hypothesis that sex hormones or other factors related to late menopause may be neuroprotective in PD. © 2021 International Parkinson and Movement Disorder Society.

Factors related to age at natural menopause in China: results from the China Kadoorie Biobank

OBJECTIVES

The aim of this study was to investigate the potentially modifiable factors affecting age at natural menopause (ANM) in Chinese women.

METHODS

We used cross-sectional data from the China Kadoorie Biobank study which that recruited 0.5 million (0.3 million women) Chinese adults aged 30 to 79 from 2004 to 2008. Multinomial logistic regression models were used to examine the relationships between ANM and various factors recorded at baseline.

RESULTS

Among 87,349 postmenopausal women, the mean ANM (SD) was 48.7 (4.3) years. Older age, being a housewife, earlier menarche, and passive smoking were associated with both premature menopause (PM, ie, ANM <40 years) and early menopause (EM, ie, ANM between 40 and 44 years). A higher odds for EM was observed in women who were widowed (odds ratio: 1.10, 95% confidence interval: 1.04-1.16), had spontaneous abortions (1.33 [1.05-1.69]), current regular smoking (1.19 [1.07-1.37]), and frequent spicy food intake (1.11 [1.05-1.08]). Higher socioeconomic status; later first birth; more live births and induced abortions; longer breastfeeding; tea drinking, as well as intakes of meat, fruits, dairy, and soybean products; and increased body mass index gain were inversely associated with PM and/or EM. In contrast, women who had more pregnancies, occasional alcohol drinking, higher levels of physical activity or body mass index, vitamin intake, and hypertension were more likely to have a later age at menopause (LM, ie, ANM ≥53 years).

CONCLUSIONS

This large epidemiological study found a wide range of sociodemographic, lifestyle, dietary, and reproductive factors related to PM, EM, and LM in Chinese women.

Establishing a reproductive biorepository for basic and translational research: experience developing the reproductive subjects registry and sample repository

PURPOSE

To report experience designing and establishing a reproductive registry and sample biorepository and to describe initial subject characteristics and biospecimens.

METHODS

Beginning in December 2017, patients presenting for reproductive care at the University of Michigan were approached for study enrollment. Following consent, subjects completed detailed reproductive and health questionnaires. A variety of reproductive specimens and tissues were collected and processed for multiple downstream applications.

RESULTS

Subject enrollment began in December of 2017. There are currently 1798 subjects enrolled. Female participants report a variety of reproductive disorders. Available samples include semen, sperm, follicular fluid, granulosa cells, immature oocytes, ovarian and uterine tissue, and blood samples.

CONCLUSION

We report the successful establishment of a reproductive registry and sample biorepository. Furthermore, we describe methods for collection and storage of a variety of reproductive tissue processed for multiple downstream translational applications.

Genetic insights into biological mechanisms governing human ovarian ageing

Reproductive longevity is essential for fertility and influences healthy ageing in women1,2, but insights into its underlying biological mechanisms and treatments to preserve it are limited. Here we identify 290 genetic determinants of ovarian ageing, assessed using normal variation in age at natural menopause (ANM) in about 200,000 women of European ancestry. These common alleles were associated with clinical extremes of ANM; women in the top 1% of genetic susceptibility have an equivalent risk of premature ovarian insufficiency to those carrying monogenic FMR1 premutations3. The identified loci implicate a broad range of DNA damage response (DDR) processes and include loss-of-function variants in key DDR-associated genes. Integration with experimental models demonstrates that these DDR processes act across the life-course to shape the ovarian reserve and its rate of depletion. Furthermore, we demonstrate that experimental manipulation of DDR pathways highlighted by human genetics increases fertility and extends reproductive life in mice. Causal inference analyses using the identified genetic variants indicate that extending reproductive life in women improves bone health and reduces risk of type 2 diabetes, but increases the risk of hormone-sensitive cancers. These findings provide insight into the mechanisms that govern ovarian ageing, when they act, and how they might be targeted by therapeutic approaches to extend fertility and prevent disease.

Searching for female reproductive aging and longevity biomarkers

Female reproductive aging is, in a way, a biological phenomenon that develops along canonical molecular pathways; however, it has particular features. Recent studies revealed complexity of the interconnections between reproductive aging and aging of other systems, and even suggested a cause-effect uncertainty between them. It was also shown that reproductive aging can impact aging processes in an organism at the level of cells, tissues, organs, and systems. Women at the end of their reproductive lives are characterized by the accelerated incidence of age-related diseases. Timing of the onset of menarche and menopause and variability in the duration of reproductive life carry a latent social risk: not having enough information about the reproductive potential, women keep on postponing childbirth. Identification and use of the most accurate and sensitive aging biomarkers enable the prediction of menopause timing and quantification of the true biological and reproductive ages of an organism. We discuss current views on reproductive aging and peculiarities of using available biomarkers of aging. We also consider latest advances in the search for potential genetic markers of reproductive aging. Finally, we posit the importance of determining the female biological age and highlight potential research directions in this area.

Associations of age at natural menopause and occupations in Chinese female workers: A cross-sectional study

AIMS

To investigate the impact of occupation types on age at natural menopause.

METHODS

This is a nation-wide cross-sectional study based on 17,948 female workers aged over 40, who come from different industries or organizations. A face-to-face standardized questionnaire was conducted in all participants with the help of occupational hygienists. Occupational titles were coded according to the International Standard Classification of Occupations (2008) (ISCO08). Cox regression model was used to assess the association between each independent occupation and menopausal timing. Models were adjusted for marriage, education, average annual family income, parity, cigarette smoking, alcohol consumption.

RESULTS

Higher risks of earlier age at natural menopause was found among legislators and senior officials (ISCO Minor group:111, HR = 2.328, P < 0.001), among other health associated professionals (ISCO Minor group: 325, HR = 1.477, P = 0.003), the workers involved in mining and mineral processing (ISCO Minor group: 811, HR = 1.515, P = 0.048) and metal processing and finishing (ISCO Minor group: 812, HR = 1.722, P < 0.001). Reduced risks of earlier age at natural menopause, including: finance professionals (ISCO Minor group: 241, HR = 0.751, P = 0.021), manufacturing and construction supervisors (ISCO Minor group: 312, HR = 0.477, P = 0.002), administrative and specialized secretaries (ISCO Minor group: 334, HR = 0.788, P = 0.045), cleaners and helpers (ISCO Minor group: 911, HR = 0.633, P = 0.01).

CONCLUSIONS

This is the first study to address the influence of occupation types on reproductive aging, showing some specific occupations could be associated with age at natural menopause. Further investigations are necessary to clarify whether it is chance finding or a true association.

The association of birthweight with age at natural menopause: a population study of women in Norway

Background

Previous studies suggest that birthweight may influence age at natural menopause, but the evidence remains inconclusive. Thus, we aimed to estimate the association of birthweight with age at natural menopause.

Methods

A retrospective population study of 164 608 women in Norway, aged 48–71 years. Data were obtained by two self-administered questionnaires among participants in BreastScreen Norway during 2006–2014. We used Cox proportional hazard models to estimate hazard ratios and logistic regression models to estimate odds ratios of menopause according to birthweight. Restricted cubic splines were applied to allow for possible non-linear associations, and adjustments were made for year and country of birth.

Results

Women with birthweight <2500 g were median 51 years at menopause (interquartile range 49–54 years), whereas women with birthweight 3500–3999 g were median 52 years at menopause (interquartile range 49–54 years). The hazard ratio of menopause decreased with increasing birthweight up until 3500 g. At birthweights >3500 g, we estimated no further decrease (P for non-linearity = 0.007). Birthweight at 2500 g increased the odds ratios of menopause before the age of 45 [1.20; 95% confidence interval (CI): 1.14–1.25] and the age of 40 (1.26; 95% CI: 1.15–1.38) compared with birthweight at 3500 g. At birthweights 4000 g and 4500 g, the odds ratio estimates were very similar to the reference group and the CIs overlapped 1.00.

Conclusions

We found a non-linear dose-relationship of birthweight with age at natural menopause, and low birthweight was associated with early natural menopause. Our findings suggest that growth restriction during fetal life may influence the timing of natural menopause.

Genome-wide meta-analysis of muscle weakness identifies 15 susceptibility loci in older men and women

Low muscle strength is an important heritable indicator of poor health linked to morbidity and mortality in older people. In a genome-wide association study meta-analysis of 256,523 Europeans aged 60 years and over from 22 cohorts we identify 15 loci associated with muscle weakness (European Working Group on Sarcopenia in Older People definition: n = 48,596 cases, 18.9% of total), including 12 loci not implicated in previous analyses of continuous measures of grip strength. Loci include genes reportedly involved in autoimmune disease (HLA-DQA1 p = 4 × 10-17), arthritis (GDF5 p = 4 × 10-13), cell cycle control and cancer protection, regulation of transcription, and others involved in the development and maintenance of the musculoskeletal system. Using Mendelian randomization we report possible overlapping causal pathways, including diabetes susceptibility, haematological parameters, and the immune system. We conclude that muscle weakness in older adults has distinct mechanisms from continuous strength, including several pathways considered to be hallmarks of ageing.

Prevalence and Risk Factors of Premature Ovarian Insufficiency/Early Menopause

Premature ovarian insufficiency (POI) and early menopause, defined as loss of ovarian activity prior to 40 years or menopause between the ages of 40 and 45 years, respectively, is associated with significant adverse health impacts. Recent data indicate that the prevalence of POI and early menopause is greater than was previously thought, affecting more than 10% of women. Biopsychosocial risk factors including genetic, autoimmune, reproductive, lifestyle, early-life, social/environmental, and iatrogenic have been associated with POI/early menopause or earlier age at menopause. However, establishing a causal role and the underlying mechanisms remains elusive. Understanding and clarification of these risk factors will facilitate prevention and risk minimization strategies to optimize women's health.

The evolutionary ecology of age at natural menopause: implications for public health

Evolutionary perspectives on menopause have focused on explaining why early reproductive cessation in females has emerged and why it is rare throughout the animal kingdom, but less attention has been given to exploring patterns of diversity in age at natural menopause. In this paper, we aim to generate new hypotheses for understanding human patterns of diversity in this trait, defined as age at final menstrual period. To do so, we develop a multilevel, interdisciplinary framework, combining proximate, physiological understandings of ovarian ageing with ultimate, evolutionary perspectives on ageing. We begin by reviewing known patterns of diversity in age at natural menopause in humans, and highlight issues in how menopause is currently defined and measured. Second, we consider together ultimate explanations of menopause timing and proximate understandings of ovarian ageing. We find that ovarian ageing is highly constrained by ageing of the follicle - the somatic structure containing the oocyte - suggesting that menopause timing might be best understood as a by-product of ageing rather than a facultative adaptation. Third, we investigate whether the determinants of somatic senescence also underpin menopause timing. We show that diversity in age at menopause can be, at least partly, explained by the genetic, ecological and life-history determinants of somatic ageing. The public health implications of rethinking menopause as the by-product rather than the catalyst of biological ageing are discussed.

Role of Ovarian Hormones in the Modulation of Sleep in Females Across the Adult Lifespan

Ovarian hormones, including 17β-estradiol, are implicated in numerous physiological processes, including sleep. Beginning at puberty, girls report more sleep complaints than boys, which is maintained throughout the reproductive life stage. Sleep problems are exacerbated during the menopausal transition, evidenced by greater risk for sleep disorders. There is emerging evidence that menopause-associated hormone loss contributes to this elevated risk, but age is also an important factor. The extent to which menopause-associated sleep disturbance persists into postmenopause above and beyond the effects of age remains unknown. Untreated sleep disturbances have important implications for cognitive health, as they are emerging as risk factors for dementia. Given that sleep loss impairs memory, an important knowledge gap concerns the role played by menopause-associated hormone loss in exacerbating sleep disturbance and, ultimately, cognitive function in aging women. In this review, we take a translational approach to illustrate the contribution of ovarian hormones in maintaining the sleep-wake cycle in younger and middle-aged females, with evidence implicating 17β-estradiol in supporting the memory-promoting effects of sleep. Sleep physiology is briefly reviewed before turning to behavioral and neural evidence from young females linking 17β-estradiol to sleep-wake cycle maintenance. Implications of menopause-associated 17β-estradiol loss is also reviewed before discussing how ovarian hormones may support the memory-promoting effects of sleep, and why menopause may exacerbate pathological aging via effects on sleep. While still in its infancy, this research area offers a new sex-based perspective on aging research, with a focus on a modifiable risk factor for pathological aging.

Association between age at menarche and age at menopause among women of an indigenous population of North Bengal, India

Menarche and menopause are two major components of a woman's reproductive life. Ages at menarche and menopause vary widely between and within populations and are influenced by various factors, both genetic and environmental. The present community-based cross-sectional investigation aimed to assess the association between ages at menarche and natural menopause among women belonging to the indigenous Rajbanshi population of North Bengal, India. The investigation was carried out from January 2015 to May 2015 among 510 Rajbanshi women aged between 45 and 55 years residing in the district of Darjeeling, West Bengal, India. A structured schedule was used to collect data on ages at menarche and natural menopause, marital status, parity, education, age of first and last pregnancies, duration of breastfeeding, nature of occupation, health status, smoking and monthly family income. Anthropometric measurements of height and weight were recorded and Body Mass Index (BMI) calculated. The statistical analyses, which included descriptive statistics and binary logistic regression (BLR), were done using SPSS. The women's mean age of menarche and median age of natural menopause were 12.52 years and 50 years, respectively. The BLR analysis indicated that education, age at first pregnancy had significant effects on the age at natural menopause among women who experienced menarche at <12 years of age (p<0.05). In the case of women who attained menarche at ≥12 years of age, marital status, age at last pregnancy, parity, education, duration of breastfeeding, smoking, occupation, monthly income and BMI had a greater influence on age at natural menopause. There appears to be an indirect association between age at menarche and age at natural menopause, along with different predictor variables, among the Rajbanshi women.

Demographic and evolutionary trends in ovarian function and aging

BACKGROUND

The human female reproductive lifespan is regulated by the dynamics of ovarian function, which in turn is influenced by several factors: from the basic molecular biological mechanisms governing folliculogenesis, to environmental and lifestyle factors affecting the ovarian reserve between conception and menopause. From a broader point of view, global and regional demographic trends play an additional important role in shaping the female reproductive lifespan, and finally, influences on an evolutionary scale have led to the reproductive senescence that precedes somatic senescence in humans.

OBJECTIVE AND RATIONALE

The narrative review covers reproductive medicine, by integrating the molecular mechanisms of ovarian function and aging with short-term demographic and long-term evolutionary trends.

SEARCH METHODS

PubMed and Google Scholar searches were performed with relevant keywords (menopause, folliculogenesis, reproductive aging, reproductive lifespan and life history theory). The reviewed articles and their references were restricted to those written in English.

OUTCOMES

We discuss and summarize the rapidly accumulating information from large-scale population-based and single-reproductive-cell genomic studies, their constraints and advantages in the context of female reproductive aging as well as their possible evolutionary significance on the life history trajectory from foetal-stage folliculogenesis until cessation of ovarian function in menopause. The relevant environmental and lifestyle factors and demographic trends are also discussed in the framework of predominant evolutionary hypotheses explaining the origin and maintenance of menopause.

WIDER IMPLICATIONS

The high speed at which new data are generated has so far raised more questions than it has provided solid answers and has been paralleled by a lack of satisfactory interpretations of the findings in the context of human life history theory. Therefore, the recent flood of data could offer an unprecedented tool for future research to possibly confirm or rewrite human evolutionary reproductive history, at the same time providing novel grounds for patient counselling and family planning strategies.

Sexual frequency is associated with age of natural menopause: results from the Study of Women's Health Across the Nation

It is often observed that married women have a later age of natural menopause (ANM) than unmarried women; however, the reason for this association is unknown. We test an original hypothesis that sexual frequency acts as a bio-behavioural mediator between marital status and ANM. We hypothesize that there is a trade-off between continued ovulation and menopause based on the woman's chances of becoming pregnant. If a woman is sexually inactive, then pregnancy is impossible, and continued investment in ovulation would not be adaptive. In addition, we test an existing hypothesis that the observed relationship is because of the exposure to male pheromones. Data from 2936 women were drawn from 11 waves of the Study of Women's Health Across the Nation, which is a longitudinal study conducted in the United States. Using time-varying Cox regression, we found no evidence for the pheromone hypothesis. However, we did observe that women who reported to have sex weekly during the study period were 28% less likely to experience menopause than women who had sex less than monthly. This is an indication that ANM may be somewhat facultative in response to the likelihood of pregnancy.

Does night work affect age at which menopause occurs?

PURPOSE OF REVIEW

To delineate the current state of evidence on the impact of night shift work on age at natural menopause.

RECENT FINDINGS

The only direct evidence is from a single observational study, which indicates that women who work night shifts are at moderately higher risk for earlier menopause and that this risk is more pronounced among younger women. Underlying biological mechanisms have yet to be sufficiently substantiated. A long-held line of inquiry, most strongly propagated by the observed link between night shift work and female breast cancer, is the 'Light at Night' hypothesis, which suggests melatonin-mediated circadian disruption as a potential regulator of reproductive signaling in women. Supporting evidence is found from observations of changes in endogenous melatonin production among night working women or in response to light exposure, and corresponding changes in endogenous ovarian hormone levels and modulated menstrual patterns, among other indications of altered central ovulation-governing processes. Susceptibility to night shift work may be modified by chronotype.

SUMMARY

This review summarizes the literature related to night work and ovulatory regulation in humans, prioritizing population-based evidence to provide motivation for the study of circadian disruption and night shift work as a regulator of menopausal timing.

Age at menopause and lung function: a Mendelian randomisation study

In observational studies, early menopause is associated with lower forced vital capacity (FVC) and a higher risk of spirometric restriction, but not airflow obstruction. It is, however, unclear if this association is causal. We therefore used a Mendelian randomisation (MR) approach, which is not affected by classical confounding, to assess the effect of age at natural menopause on lung function.

We included 94 742 naturally post-menopausal women from the UK Biobank and performed MR analyses on the effect of age at menopause on forced expiratory volume in 1 s (FEV1), FVC, FEV1/FVC, spirometric restriction (FVC<lower limit of normal (LLN)) and airflow obstruction (FEV1/FVC<LLN). We used the inverse variance-weighted method, as well as methods that adjust for pleiotropy, and compared MR with observational analyses.

The MR analyses showed higher FEV1/FVC and a 15% lower risk of airflow obstruction for women with early (<45 years) compared to normal (45–55 years) menopause. Despite some evidence of pleiotropy, the results were consistent when using MR methods robust to pleiotropy. Similar results were found among never- and ever-smokers, while the protective effect seemed less strong in women who had ever used menopause hormone treatment and in overweight women. There was no strong evidence of an association with FVC or spirometric restriction. In observational analyses of the same dataset, early menopause was associated with a pronounced reduction in FVC and a 13% higher risk of spirometric restriction.

Our MR results suggest that early menopause has a protective effect on airflow obstruction. Further studies are warranted to better understand the inconsistency with observational findings, and to investigate the underlying mechanisms and role of female sex hormones.

Rotating night shift work and menopausal age

STUDY QUESTION

How are rotating night shift schedules associated with age at menopause among a large, national cohort of shift working nurses?

SUMMARY ANSWER

Our findings suggest that working rotating night shifts with sufficient frequency may modestly accelerate reproductive senescence among women who may already be predisposed to earlier menopause.

WHAT IS KNOWN ALREADY

Younger age at menopause has been associated with increased risk of adverse health outcomes, particularly those linked to reproduction. Night work has been associated with reproductive dysfunction, including disruption of menstrual cycle patterns.

STUDY DESIGN, SIZE, DURATION

This cohort study was conducted among 80 840 women of the Nurses' Health Study 2 (NHS2), with prospective follow-up from 1991 through 2013. Loss-to-follow-up of the NHS2 is estimated to be <10%.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We assessed the association between cumulative and current rotating night shift work and age at natural menopause over 22 years of follow-up (1991-2013). Cox proportional hazards models were used to estimate hazard ratios (HR) for menopause, adjusted for age, smoking status, body mass index, physical activity, alcohol consumption, reproductive factors and exogenous hormone use.

MAIN RESULTS AND THE ROLE OF CHANCE

Over follow-up, 27 456 women (34%) reached natural menopause. Women who worked 20 or more months of rotating night shifts in the prior 2-year had an increased risk of earlier menopause (multivariable-adjusted (MV)-HR = 1.09, 95% CI: 1.02-1.16) compared to women without rotating night shift work. This risk was stronger among women undergoing menopause or otherwise censored under age 45 years (MV-HR = 1.25, 95% CI: 1.08-1.46), than it was for those continuing in the study when >45 years old (MV-HR = 1.05, 95% CI: 0.99-1.13). Working 10 or more years of cumulative rotating night work was also associated with higher risk of menopause among women reaching menopause under age 45 (MV-HR10-19 years = 1.22, 95% CI: 1.03-1.44; MV-HR≥20 years = 1.73, 95% CI: 0.90-3.35), though not over the age of 45 years (MV-HR10-19 years = 1.04, 95% CI: 0.99-1.10; MV-HR≥20 years = 1.01, 95% CI: 0.89-1.15).

LIMITATIONS, REASONS FOR CAUTION

The degree to which observed effects of rotating night shifts on age at natural menopause are due to circadian disruption, rather than fatigue and stress associated with working more demanding schedules, is uncertain due to potential residual confounding by these factors.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first study to assess the effects of night work on menopausal timing among a larger national cohort of shift working women. Women already prone to earlier menopause may further truncate their reproductive lifetime by working schedules comprising day as well as night shifts.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by Center for Disease Control and Prevention/The National Institute for Occupational Safety and Health Grant 5R01OH009803 (PI: Schernhammer E), as well as UM1 CA176726 from the National Institute of Health. The funding sources had no role in the design and conduct of the study; collection, management, analysis and interpretation of the data; preparation, review or approval of the article; and decision to submit the article for publication. The authors have no conflicts of interest.

Prolonged Amenorrhea and Resumption of Menses in Women with HIV

OBJECTIVE

To compare etiologies of prolonged amenorrhea in a cohort of HIV-infected women with a cohort of similar uninfected at-risk women.

MATERIALS AND METHODS

Women from the Women's Interagency HIV Study were seen every 6 months, and completed surveys including questions about their menstruation. Those who reported no vaginal bleeding for at least 1 year ("prolonged amenorrhea") with subsequent resumption of bleeding were compared with women in whom bleeding had stopped permanently ("menopause"). Characteristics associated with reversible prolonged amenorrhea were ascertained.

RESULTS

Of 828 women with prolonged amenorrhea, 37.6% had reversible amenorrhea and 62.4% never resumed menses. HIV-seropositive women with prolonged amenorrhea were significantly younger at cessation of menses than HIV-negative women (p < 0.0001). Of those with reversible prolonged amenorrhea, approximately half were taking medications associated with amenorrhea, including 95 (30.6%) hormonal contraception, 80 (25.7%) opiates/stimulants, 16 (5.1%) psychotropic medications, and 6 (1.9%) chemotherapy. HIV-seropositive women were less likely to have medications as a cause of amenorrhea than seronegative women (p = 0.02). In multivariable analysis, women with reversible prolonged amenorrhea of unknown etiology were younger (p < 0.0001), more often obese (p = 0.03), and less educated (p = 0.01) than those with permanent amenorrhea. Among HIV-seropositive women, markers of severe immunosuppression were not associated with prolonged amenorrhea.

CONCLUSION

Women with HIV infection have unexplained prolonged amenorrhea more often than at-risk seronegative women. This is especially common among obese, less-educated women. Prolonged amenorrhea in the HIV-seropositive women should be evaluated and not be presumed to be to the result of menopause.

The relation of age at menarche with age at natural menopause: a population study of 336 788 women in Norway

STUDY QUESTION

Is age at menarche associated with age at menopause or with duration of the reproductive period (interval between menarche and menopause)?

SUMMARY ANSWER

The association of age at menarche with age at menopause was weak and non-linear, and the duration of the reproductive period decreased by increasing age at menarche.

WHAT IS KNOWN ALREADY

It remains uncertain whether age at menarche is associated with age at menopause. Some studies report that women with early menarche also have early menopause. Other studies report that women with early menarche have late menopause, or they report no association. The duration of the reproductive period may be an indicator of the cumulative endogenous exposure to estrogens and progestogens during life course and is associated with risk of breast cancer and endometrial cancer.

STUDY DESIGN, SIZE, DURATION

A retrospective cohort study of 336 788 women, aged 48-71 years, in the BreastScreen Norway during the years 2006-2014 was performed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Information about age at menarche and menopausal status was obtained by self-administered questionnaires. We used time to event approaches to estimate the associations.

MAIN RESULTS AND THE ROLE OF CHANCE

Median age at menopause was 51 years in most menarche groups. Women with menarche at age 16 years or age ≥ 17 years had menopause 1 year later [median: 52 years, interquartile range (IQR): 49-54 years] than women with menarche at age 13 years (median: 51 years, IQR: 49-54 years, reference) (crude hazard ratio (HR) = 0.95; 95% CI: 0.93-0.97 and 0.95; 95% CI: 0.92-0.99, Pnon-linearity < 0.001). The reproductive period decreased with increasing age at menarche (Pnon-linearity < 0.001), and women with menarche at age ≤ 9 years had 9 years longer median reproductive period than women with menarche at age ≥ 17 years (median: 43 versus 34 years). Adjustment for year of birth did not change the HR estimates notably.

LARGE SCALE DATA

Not applicable.

LIMITATIONS, REASONS FOR CAUTION

Information about age at menarche and age at menopause was based on self-reports. Particularly for age at menarche, the long time interval between the event and data collection may have caused imprecise reporting.

WIDER IMPLICATIONS OF THE FINDINGS

Our study suggests that age at menarche is a strong indicator for the duration of women's reproductive period. Our findings should encourage studies of the independent role of duration of the reproductive period on the risk of breast cancer and endometrial cancer, since these cancers have been associated with exposure to estrogens and progestogens.

STUDY FUNDING/COMPETING INTEREST(S)

The present study was funded by the Norwegian Cancer Society [Grant number 6863294-2015]. The authors declare no conflicts of interest.

Is in utero exposure to maternal socioeconomic disadvantage related to offspring ovarian reserve in adulthood?

BACKGROUND

Because the ovarian follicle pool is established in utero, adverse exposures during this period may be especially impactful on the size and health of the initial follicle endowment, potentially shaping trajectories of ovarian follicle loss and the eventual onset of menopause. Building on a robust literature linking socioeconomic status (SES) and menopausal timing, the current study examined adverse prenatal exposures related to maternal SES, hypothesizing that greater maternal socioeconomic disadvantage would be associated with lower ovarian reserve in the adult offspring.

METHODS

In a healthy, community-based sub-sample (n = 350) of reproductive age participants in the OVA Study (2006-2011), prenatal maternal SES was examined in relation to two biomarkers of ovarian reserve, antimullerian hormone (AMH) and antral follicle count (AFC). Prenatal maternal SES was assessed indirectly using maternal addresses abstracted from participant birth certificates, geocoded, and linked to US Census-derived variables, including neighborhood-level characteristics: education (% of individuals with a HS diploma); poverty (% of families below the poverty line); unemployment (% of individuals > 16 years who are unemployed); and income (median family income).

RESULTS

In separate covariate-adjusted linear regression models (following the backward elimination of main effects with P > .10), greater maternal neighborhood education was related to higher ovarian reserve as marked by higher levels of offspring AMH (beta = .142, P < .001) and AFC (beta = .092, P < .10) with models accounting for 19.6% and 21.5% of the variance in AMH and AFC, respectively. In addition, greater maternal neighborhood poverty was related to lower ovarian reserve as marked by lower offspring AMH (beta = -.144, P < .01), with the model accounting for 19.5% of the variance in AMH.

CONCLUSIONS

Maternal socioeconomic disadvantage measured indirectly at the neighborhood level was associated with lower ovarian reserve among the adult offspring, independently of offspring SES and other potential confounding factors. This suggests SES-related adversity exposures may have a detrimental impact on the size or health of the initial follicle endowment, leading to accelerated follicle loss over time.

Role of amygdala kisspeptin in pubertal timing in female rats

To investigate the mechanism by which maternal obesity disrupts reproductive function in offspring, we examined Kiss1 expression in the hypothalamic arcuate (ARC) and anteroventral periventricular (AVPV) nuclei, and posterodorsal medial amygdala (MePD) of pre-pubertal and young adult offspring. Sprague-Dawley rats were fed either a standard or energy-dense diet for six weeks prior to mating and throughout pregnancy and lactation. Male and female offspring were weaned onto normal diet on postnatal day (pnd) 21. Brains were collected on pnd 30 or 100 for qRT-PCR to determine Kiss1 mRNA levels. Maternal obesity increased Kiss1 mRNA expression in the MePD of pre-pubertal male and female offspring, whereas Kiss1 expression was not affected in the ARC or AVPV at this age. Maternal obesity reduced Kiss1 expression in all three brain regions of 3 month old female offspring, but only in MePD of males. The role of MePD kisspeptin on puberty, estrous cyclicity and preovulatory LH surges was assessed directly in a separate group of post-weanling and young adult female rats exposed to a normal diet throughout their life course. Bilateral intra-MePD cannulae connected to osmotic mini-pumps for delivery of kisspeptin receptor antagonist (Peptide 234 for 14 days) were chronically implanted on pnd 21 or 100. Antagonism of MePD kisspeptin delayed puberty onset, disrupted estrous cyclicity and reduced the incidence of LH surges. These data show that the MePD plays a key role in pubertal timing and ovulation and that maternal obesity may act via amygdala kisspeptin signaling to influence reproductive function in the offspring.

Factors associated with early menopause among women in Nigeria

OBJECTIVES

Effective antiretroviral therapy has prolonged the survival of patients with HIV. Accordingly, studies of the consequences of ageing are increasingly important. We determined the prevalence of early menopause (EM) and its associated factors in a cohort of HIV-infected and HIV-negative controls in Jos, Nigeria.

METHODS

HIV-infected women accessing care in an ambulatory setting and their negative counterparts from the general population were included. Menopause was defined as having gone one year since the last menstrual period. EM was defined as the onset of menopause at ≤45 years of age. Baseline characteristics were compared and logistic regression analyses were used to determine factors independently associated with EM.

RESULTS

Out of a total of 253 women included, 58 attained menopause early, giving an EM prevalence of 22.9% (95% confidence interval [CI] 17.9-28.6%). Women with EM were younger (P<0.001) and had been infected with HIV for a shorter period (P=0.007). Baseline CD4+ cell count (P=0.66) and viral load (P=0.15) were similar among those with and without EM. For all subjects, HIV infection (adjusted odds ratio [AOR}=10.95, 95% CI 1.39-86.33) and sexual activity (AOR=2.37, 95% CI 1.24-4.52) were associated with EM while early menarche (AOR=14.88, 95% CI 1.37-161.10) and sexual activity (AOR=2.02, 95% CI 1.03-3.96) were independently associated with EM.

CONCLUSION

Over a quarter of our postmenopausal women attained menopause early. No HIV-related factor predicted EM in this study. A better understanding of ageing in these women is important to determine a more appropriate disease-management approach during this period of life.

Association of Female Reproductive Factors with Hypertension, Diabetes and LQTc in Chinese Women

The association of female reproductive factors (FRFs) with cardiovascular risk factors among different population was variable and inconsistent. The objective of this study was to examine the association between FRFs and hypertension, type 2 diabetes mellitus (DM), and long heart-rate-corrected QT interval (LQTc) in Chinese post-menopausal women (Post-MW). A total of 8046 Post-MW from the China Chaoshan Biobank Cohort Study were included for analysis. Logistic regression and general linear regression models were used to estimate the association between FRFs and hypertension, DM, and LQTc. Compared with women with 0 or 1 live birth, increasing risk of hypertension (odds ratio [OR], 1.51; 95% confidence interval [CI], 1.16-1.96), DM (OR, 1.65; 95% CI, 1.22-2.22), and LQTc (OR, 1.45; 95% CI, 1.01-2.09) were observed in women who had five or more live births. Further analysis demonstrated that the association between parity and hypertension, DM, and LQTc was mediated by lifestyle and dyslipidemia. Women with more live births had increased body mass index and waist circumstance, and were inclined to consume more salty food, animal fat, and alcohol, but less meat, vegetable, fish, plant oil, and tea, compared with that had fewer live births (all P < 0.05).

Correlation of age at natural menopause with occupational status and other epidemiologic factors in women from Prefecture of Kavala, Greece

AIM

Aim of this study was to explore possible associations between the timing of natural menopause and occupational status and other determinant epidemiologic factors among women living in the Prefecture of Kavala, a region of North-East Greece.

METHODS

The sample of the study comprised of 827 naturally menopausal women, who consented to participate in this questionnaire-based interview study between 2011 and 2016. The study population was recruited from women who were hospitalized or visited the outpatient clinics of the General Hospital of Kavala and women working in the public sector services and private companies in the Prefecture of Kavala.

RESULTS

The mean age of the sample at natural menopause was 49.1 years; 12.2 % had early menopause, and 4.5 % were diagnosed with premature ovarian failure. For the majority of enrolled women (80.5 %) menopause occurred between 45-54 years, and for the rest (2.8 %) after 54 years of age. In univariate analysis, a statistically significant correlation was found between age at menopause and occupational status, year of birth, mother's age at menopause, age at menarche, and high levels of chronic stress. Multiple regression analysis revealed that occupational status, year of birth and mother's natural menopausal age could predict age at menopause.

CONCLUSION

Socioeconomic, demographic and familial variables appear to be associated with age at natural menopause in a representative sample of women in the Prefecture of Kavala, Greece. HIPPOKRATIA 2017, 21(1): 32-37.

Biobanking of different body fluids within the frame of IVF-a standard operating procedure to improve reproductive biology research

Purpose

The aim of the present study was to develop a standard operating procedure (SOP) for the collection, transport, and storage of human cumulus cells, follicular fluid, blood serum, seminal plasma, embryo culture supernatant, and embryo culture supernatant control obtained within the IVF process under approved protocols and written informed consent from participating patients. The SOP was developed at the Kinderwunsch Institut Schenk, Dobl, Austria, together with Biobank Graz of the Medical University of Graz, Austria.

Methods

The SOP provides comprehensive details of laboratory procedures and sampling of the different fluids within the IVF process. Furthermore, information on sample coding, references of involved laboratory techniques (e.g., oocyte retrieval with a Steiner-TAN needle), ethical approvals, and biobanking procedures are presented.

Results

The result of the present study is a standard operating procedure.

Conclusions

The SOP ensures a professional way for collection and scientific use of IVF samples by the Kinderwunsch Institut Schenk, Dobl, Austria, and Biobank Graz of the Medical University of Graz, Austria. It can be used as a template for other institutions to unify specimen collection procedures in the field of reproductive health research.