Life course exposure to smoke and early menopause and menopausal transition

Use of cigarettes and heated tobacco products during pregnancy and maternal-fetal outcomes: a retrospective, monocentric study

PURPOSE

To compare the effects of using heated tobacco products (HTP) or traditional cigarettes (C) on maternal and neonatal outcomes.

METHODS

This is a retrospective, monocentric study conducted at San Marco Hospital from July 2021 to July 2022. We compared a cohort of pregnant patients who smoked HTP (HS), with pregnant women smoking cigarettes (CS), ex-smoker (ES) and non-smoker (NS) pregnant women. Biochemistry, ultrasound, and neonatal evaluations were performed.

RESULTS

In total, 642 women were enrolled, of which 270 were NS, 114 were ES, 120 were CS, and 138 were HS. CS had the greatest weight gain and had more difficulty getting pregnant. Smokers and ES experienced more frequently threats of preterm labor, miscarriages, temporary hypertensive spikes, and higher rates of cesarean sections. Preterm delivery was more associated with CS and HS groups. CS and HS had lower awareness of the risks to which the mother and the fetus are exposed. CS were more likely to be depressed and anxious. Biochemical parameters did not show significant differences between the groups. CS had the greatest difference in days between the gestational age calculated based on the last menstrual period and the one based on the actual ultrasound age. The average percentile newborn weight range of CS was lower, as well as the mean 1st minute and the 5th minute Apgar scores.

CONCLUSION

The comparison of the data obtained between CS and HS underlines the greater danger of C. Nevertheless, we do not recommend HTP because the maternal-fetal outcomes are not superimposable to the NS outcomes.

"Inhaling hazards, exhaling insights: a systematic review unveiling the silent health impacts of secondhand smoke pollution on children and adolescents

The health risks of smoking are widely known, but the impact of secondhand smoke on children and adolescents is often underestimated. Despite efforts to reduce smoking, exposure to secondhand smoke remains a significant public health concern, especially for young individuals. This systematic review aims to explore the health impacts of secondhand smoking on children and adolescents. Following PRISMA guidelines, 18 eligible studies from 8 countries published between 2015 and 2023 were identified through PubMed, SCOPUS, and Web of Science databases. Findings revealed that passive smoking is associated with respiratory issues like asthma and respiratory infections in children and adolescents aged 4 months to 18 years. Significant correlations were found between asthma severity and cotinine levels, a marker of passive smoking. Additionally, metabolic issues, cardiovascular effects, and ophthalmological changes, and alterations in neurocognitive functions, were noted. Urgent public health interventions are needed to reduce smoking prevalence and protect this vulnerable demographic.

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.

The causal association between smoking initiation, alcohol and coffee consumption, and women's reproductive health: A two-sample Mendelian randomization analysis

Objective: A number of epidemiological studies have demonstrated that smoking initiation and alcohol and coffee consumption were closely related to women's reproductive health. However, there was still insufficient evidence supporting their direct causality effect. Methods: We utilized two-sample Mendelian randomization (TSMR) analysis with summary datasets from genome-wide association study (GWAS) to investigate the causal relationship between smoking initiation, alcohol and coffee consumption, and women's reproductive health-related traits. Exposure genetic instruments were used as variants significantly related to traits. The inverse-variance weighted (IVW) method was used as the main analysis approach, and we also performed MR-PRESSO, MR-Egger, weighted median, and weighted mode to supplement the sensitivity test. Then, the horizontal pleiotropy was detected by using MRE intercept and MR-PRESSO methods, and the heterogeneity was assessed using Cochran's Q statistics. Results: We found evidence that smoking women showed a significant inverse causal association with the sex hormone-binding globulin (SHBG) levels (corrected β = -0.033, p = 9.05E-06) and age at menopause (corrected β = -0.477, p = 6.60E-09) and a potential positive correlation with the total testosterone (TT) levels (corrected β = 0.033, p = 1.01E-02). In addition, there was suggestive evidence for the alcohol drinking effect on the elevated TT levels (corrected β = 0.117, p = 5.93E-03) and earlier age at menopause (corrected β = -0.502, p = 4.14E-02) among women, while coffee consumption might decrease the female SHBG levels (corrected β = -0.034, p = 1.33E-03). Conclusion: Our findings suggested that smoking in women significantly decreased their SHBG concentration, promoted earlier menopause, and possibly reduced the TT levels. Alcohol drinking had a potential effect on female higher TT levels and earlier menopause, while coffee consumption might lead to lower female SHBG levels.

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.

Single-nucleus RNA Sequencing reveals the mechanism of cigarette smoke exposure on diminished ovarian reserve in mice

The systematic toxicological mechanism of cigarette smoke (CS) on ovarian reserve has not been extensively investigated. Female 8-week-old C57BL/6 mice at peak fertility were exposed to CS or indoor air only for 30 days (100 mice per group) and the effects of CS on ovarian reserve were assessed using Single-Nucleus RNA Sequencing (snRNA-seq). In addition, further biochemical experiments, including immunohistochemical staining, ELISA, immunofluorescence staining, transmission electron microscopy, cell counting kit-8 assay, flow cytometry analysis, senescence-associated β-galactosidase staining, and western blotting, were accomplished to confirm the snRNA-seq results. We identified nine main cell types in adult ovaries and the cell-type-specific differentially expressed genes (DEGs) induced by CS exposure. Western blot results verified that down-regulation of antioxidant genes (Gpx1 and Wnt10b) and the steroid biosynthesis gene (Fdx1) occurred in both ovarian tissue and human granulosa cell-like tumor cell line (KGN cells) after CS exposure. Five percent cigarette smoke extract (CSE) effectively stimulated the production of reactive oxygen species (ROS), DNA damage, cellular senescence and markedly inhibited KGN cell proliferation by inducing G1-phase cell cycle arrest. Moreover, down-regulation of Gja1, Lama1 and the Ferroptosis indicator (Gpx4) in granulosa cells plays a significant role in ultrastructural changes in the ovary induced by CS exposure. These observations suggest that CS exposure impaired ovarian follicle reserve might be caused by REDOX imbalance in granulosa cells. The current study systematically determined the damage caused by CS in mouse ovaries and provides a theoretical basis for early clinical prediction, diagnosis and intervention of CS exposure-associated primary ovarian insufficiency (POI), and is of great significance in improving female reproductive health.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

Premature menopause among women in India: Evidence from National Family Health Survey-IV

AIM

Women who experience premature menopause either due to biological or induced reasons have a longer duration of exposure to severe symptoms and adverse health consequences when compared to those who undergo menopause at later age. Despite the fact that premature menopause has a profound effect on the health of women, there has been limited study on this issue. Therefore, this study attempted to determine the prevalence and factors associated with premature menopause among 302 557 women aged 25-39 years in India.

METHODS

This study utilized secondary data from the fourth round of the National Family Health Survey-IV (NFHS-4), conducted during 2015-2016 in India. Descriptive statistics and multinomial logistic regression were used for statistical analyses of the data.

RESULTS

The results revealed that the prevalence of premature menopause in this sample of Indian women was 3.7%, out of which 2.1% of women had experienced natural premature menopause, whereas 1.7% had surgical premature menopause. The prevalence of premature menopause was highest in the southern region of India. Factors like age, education, wealth index, place of residence, smoking status, children ever born, age at first birth, use of hormonal contraception, sterilization, and body mass index were found to be associated with premature menopause in India.

CONCLUSION

A sizeable proportion of women in India are attaining menopause prematurely. Furthermore, the percentage and likelihood of experiencing premature menopause are relatively high among rural women, women with higher parity, early age at childbearing, and women who smoke.

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.

Benign breast disease and changes in mammographic breast density

Background

Mammographic breast density (MBD) and benign breast disease (BBD) are two of the strongest risk factors for breast cancer. Understanding trends in MBD by age and parity in women with BBD is essential to the clinical management and prevention of breast cancer.

Methods

Using data from the Early Determinants of Mammographic Density (EDMD) study, a prospective follow-up study of women born in 1959–1967, we evaluated MBD in 676 women. We used linear regression with generalized estimating equations to examine associations between self-reported BBD and MBD (percent density, dense area, and non-dense area), assessed through a computer-assisted method.

Results

A prior BBD diagnosis (median age at diagnosis 32 years) was reported by 18% of our cohort. The median time from BBD diagnosis to first available study mammogram was 9.4 years (range 1.1–27.6 years). Women with BBD had a 3.44% higher percent MBD (standard error (SE) = 1.56, p-value = 0.03) on their first available mammogram than women without BBD. Compared with parous women without BBD, nulliparous women with BBD and women with a BBD diagnosis prior to first birth had 7–8% higher percent MBD (β = 7.25, SE = 2.43, p-value< 0.01 and β = 7.84, SE = 2.98, p-value = 0.01, respectively), while there was no difference in MBD in women with a BBD diagnosis after the first birth (β = −0.22, SE = 2.40, p-value = 0.93).

Conclusion

Women with self-reported BBD had higher mammographic breast density than women without BBD; the association was limited to women with BBD diagnosed before their first birth.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-021-01426-7.

Ovariectomy enhances female rats' susceptibility to metabolic, oxidative, and heat shock response effects induced by a high-fat diet and fine particulate matter

Obesity and exposure to fine particulate matter (air pollutant PM_2.5) are important risk factors for metabolic and cardiovascular diseases. They are also related to early menopause. The reduction of 17β-estradiol (E2) levels during female climacteric, marked by menopause, is of significant concern because of its imminent influence on metabolism, redox and inflammatory status. This complex homeostasis-threatening scenario may induce a heat shock response (HSR) in cells, enhancing the expression of the 70 kDa heat shock protein (HSP70). A failure in this mechanism could predispose women to cardiovascular diseases. In this study, we evaluated if the climacteric could represent an additional risk among obese rats exposed to PM_2.5 by worsening lipid, oxidative, and inflammatory parameters and HSP70 in cardiac tissue. We induced obesity in female Wistar rats using a high-fat diet (HFD) (58.3% as fats) and exposed them to 50 μL of saline 0.9% (control, n = 15) or 250 μg residual oil fly ash (ROFA, the inorganic portion of PM_2.5) (polluted, n = 15) by intranasal instillation, 5 days/w for 12 weeks. At the 12th week, we subdivided these animals into four groups: control (n = 6), OVX (n = 9), polluted (n = 6) and polluted + OVX (n = 9). OVX and polluted + OVX were submitted to a bilateral ovariectomy (OVX), a surgical model for menopause, while control and polluted received a false surgery (sham). ROFA exposure and HFD consumption were continued for 12 additional weeks, after which the animals were euthanized. ROFA enhanced the susceptibility to ovariectomy-induced dyslipidemia, while ovariectomy predisposed female rats to the ROFA-induced decrease of cardiac iHSP70 expression. Ovariectomy also decreased the IL-6 levels and IL-6/IL-10 in obese animals, reinforcing a metabolic impairment and a failure to respond to unfavorable conditions. Our results support the hypothesis that obese ovariectomized animals are predisposed to a metabolic worsening under polluted conditions and are at higher risk of cardiovascular diseases.

An Appraisal of the Role of Previously Reported Risk Factors in the Age at Menopause Using Mendelian Randomization

Objective

Menopause at a young age is associated with many health problems in women, including osteoporosis, depressive symptoms, coronary disease, and stroke. Many traditional observational studies have reported some potential risk factors for early menopause but have drawn different conclusions. This inconsistency can be attributed mainly to unmodified confounding factors. Identifying the factors causally associated with age at menopause is important for early intervention in women with abnormal menopause timing, and for improving the quality of life for postmenopausal women. This study aims to appraise whether the previously reported risk factors are causally associated with early age at natural menopause (ANM) susceptibility.

Methods

We used Mendelian randomization, a statistical method wherein genetic variants are used to determine whether an observational association between a risk factor and an outcome is consistent with a causal effect.

Results

Women with earlier age at menarche (β = 0.34, se = 0.16, p = 0.035), lower education level (β = 1.19, se = 0.41, p = 0.004) and higher body mass index (β = −0.05, se = 0.02, p = 0.027) had greater risk for early ANM. The causal link between early age at menarche and early ANM was replicated using ReproGen consortium data (β = 0.23, se = 0.07, p = 0.001). However, a current smoking habit, one of previously reported risk factors, was less likely to be correlated causally with early ANM, suggesting that previous observational studies may not have sufficiently adjusted for confounders.

Conclusion

Our results help to identify the risk factors of ANM via a genetics approach and future research into the biological mechanism could further help with targeted prevention for early menopause.

Trends of Premature and Early Menopause: a Comparative Study of the US National Health and Nutrition Examination Survey and the Korea National Health and Nutrition Examination Survey

BACKGROUND

While evidence shows a tendency toward delays in menopause worldwide, whether prevalence of premature (< 40 years) or early menopause (40-44 years) is also reduced in different ethnic groups is uncertain. The aim of this study was to explore birth cohort effect in the prevalence of premature and early menopause in United States (US) and Korea.

METHODS

This is a retrospective study using the National Health and Nutrition Examination Survey (NHANES, 1999-2014) and the Korea NHANES (KNHANES, 2007-2012). We analyzed prevalence of premature and early menopause in three ethnic groups of US and Korea. We restricted our analysis to women aged ≥ 45 years at the time of the survey born between 1920 and 1969. The data of both eligible 9,209 US women and 9,828 Korean was included in final analysis. We calculated odds ratios (OR) for each outcome adjusting for biological and socioeconomic factors, respectively.

RESULTS

Prevalence of premature menopause was 1.7% in US, 2.8% in Korean women. Early menopause occurred in 3.4% and 7.2% of US and Korean, respectively. In US women, prevalence of premature and early menopause did not change and did not differ across three ethnicities. Korean women showed highest and consistently decreasing prevalence (P < 0.001). When we adjusted for covariates, birth lower risk for premature menopause was evident in US Non-Hispanic black born in 1950s and in Korean born between 1940s and 1960s compared to those born in 1920s. In the analysis of early menopause, excluding premature menopause patients, lower risk of more recent generation (born in 1940s and later) was evident in Korean women.

CONCLUSION

The trend and birth cohort effect in occurrence of premature and early menopause among the US and Korea women are different. Prevalences of premature and early menopause decrease only in Korean.

The many menopauses: searching the cognitive research literature for menopause types

Objective:

Recent evidence suggests that early or induced menopause increases the risk for cognitive impairment and dementia. Given the potential for different cognitive outcomes due to menopause types, it is important that present research on menopause and cognition distinguishes between types. The aim of this project was to determine to what extent research looking at cognition in postmenopausal women published in one year, 2016, accounted for menopausal type.

Methods:

We searched MEDLINE, EMBASE, and PsychINFO using keywords and MeSH terms for menopause and cognition. We included any research paper reporting a cognitive outcome measure in a menopausal human population. Differentiation between the types of menopause was defined by four categories: undifferentiated, demographic differentiation (menopause type reported but not analyzed), partial differentiation (some but not all types analyzed), and full differentiation (menopause types factored into analysis, or recruitment of only one type).

Results:

Fifty research articles were found and analyzed. Differentiation was distributed as follows: undifferentiated, 38% (19 articles); demographic differentiation, 16% (8); partial differentiation, 28% (14); and full differentiation, 18% (9).

Conclusions:

This review revealed that although some clinical studies differentiated between the many menopauses, most did not. This may limit their relevance to clinical practice. We found that when menopause types are distinguished, the differing cognitive outcomes of each type are clarified, yielding the strongest evidence, which in turn will be able to inform best clinical practice for treating all 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.

Early Age at Natural Menopause Is Related to Lower Post-Bronchodilator Lung Function. A Longitudinal Population-based Study

Rationale: Poor lung function, a significant predictor of mortality, has been observed in postmenopausal women compared with those still menstruating. Menopausal age is a risk factor for several adverse health outcomes, but little evidence exists on the impact of menopausal age on lung function impairments, especially regarding post-bronchodilator lung function measures.Objectives: To investigate the association between age at menopause and pre- and post-bronchodilator lung function outcomes.Methods: During the sixth-decade follow-up of the Tasmanian Longitudinal Health Study cohort (mean age, 53 yr), information was collected on most recent menstrual period and menopausal status. Lung function was measured at age 7 years and again at 53 years. Multiple linear regression was performed to determine the association between age at menopause and pre- and post-bronchodilator spirometry, controlling for early and adult life confounders.Results: Women reporting an early age at natural menopause (<45 yr) had lower post-bronchodilator forced expiratory volume in 1 second (-168 ml; 95% confidence interval, -273 to -63) and lower forced vital capacity (-186 ml; 95% confidence interval, -302 to -70) than postmenopausal women who experienced menopause at a later age (≥45 yr). No association was observed with forced expiratory volume in 1 second/forced vital capacity ratio. Adjustment for early-life confounders strengthened these associations.Conclusions: This study provides new evidence that early menopause is associated with reduced lung function that is suggestive of restriction, but not obstruction, even after adjustment for early-life confounders. Given the important link between poor lung function and mortality, clinicians should be aware of the risk of diminished lung function in postmenopausal women who experience menopause at an early age.

Early menarche and premature natural menopause in Indonesia

BACKGROUND

An association has been suggested between early menarche and premature natural menopause. However, existing studies in developed countries show mixed findings.

AIM

This study examined whether early menarche (first menstrual period ≤11 years old) is a factor for premature natural menopause (final menstrual period <40 years old) in the context of a developing country.

SUBJECTS AND METHODS

Data came from the Indonesia Family Life Survey (IFLS) 2014, which consists of 1608 post-menopausal women.

RESULTS

Results of hierarchical logistic regression show that women who experienced early menarche (first menstrual period ≤11 years old) were found to be at higher risk of premature natural menopause (β = 0.94, p < 0.01, CI = 0.24-1.63). The results are robust against potential confounding factors including individual reproductive history, lifestyle and sociodemographic characteristics, as well as unobserved factors at the household and community levels.

CONCLUSION

The findings support early monitoring of women with early menarche, especially those who have no children, for preventive health interventions aimed at mitigating the risk of adverse health outcomes associated with premature natural menopause.

Passive smoking induces pediatric asthma by affecting the balance of Treg/Th17 cells

BACKGROUND

We aimed to explore the effects of passive smoking on the severity of pediatric asthma and associated molecular mechanisms.

METHODS

A total of 378 children with asthma were assigned into four groups according to asthma severity (from grades I to IV). Univariate and multivariate regression analyses were used to analyze possible factors associated with asthma severity in children. Environmental tobacco smoke (ETS) exposure was measured via cotinine concentration in urine. Serum levels of immunoglobulin E (IgE) and cytokines were measured using allergen diagnostic and ELISA (enzyme-linked immunosorbent assay) kits. The percentage of T-regulatory (Treg) and T-helper type 17 (Th17) cells in peripheral blood mononuclear cells (PMBCs) were measured by flow cytometry. Treg- and Th17-associated transcription factors from PMBCs were measured by using ELISA kits.

RESULTS

The levels of ETS and serum IgE, and the duration and amounts of passive smoking were closely associated with asthma severity. Passive smoking significantly reduced the levels of FoxP3 (Forkhead/winged helix transcription factor) and tumor growth factor-β, which were associated with Treg cells, and increased the levels of interleukin-17A and interleukin-23, which were associated with Th17 cells. Meanwhile, passive smoking significantly reduced the ratio of Treg/Th17 cells (P < 0.05).

CONCLUSIONS

Passive smoking was closely associated with the severity of childhood asthma by affecting the balance of Treg/Th17 cells.

Factors related to age at menopause among Korean women: the Korean Longitudinal Survey of Women and Families

OBJECTIVE

The purpose of this study was to explore factors influencing age of menopause among Korean women.

METHODS

For this secondary analysis study, panel data for Waves 4 through 6 of the Korean Longitudinal Survey of Women were used. Women aged 40 to 60 who were menstruating at Wave 4 were included in the analysis (N = 5,437). Sociodemographic, health status, and health behavioral factors were examined to explore their influence on menopause using Kaplan-Meier analysis and Cox regression analysis.

RESULTS

Korean women who perceived themselves to be overweight or obese, who had depressive symptoms, or who smoked or were current smokers had higher probabilities of experiencing the onset of menopause, whereas those who had educational achievement lower than high school had a lower probability of experiencing the onset menopause.

CONCLUSIONS

Various factors influenced menopause, including sociodemographic, health status, and health behaviors. Specific tailored interventions for the management of depressive symptoms and smoking cessation could be developed to target modifying variables for Korean women, in preparation for menopause. Also, the role of perceived body weight on menopause could be further explored to identify sociocultural factors for age at menopause.

In-utero cigarette smoke exposure and the risk of earlier menopause

OBJECTIVE

Cigarette smoking is a risk factor for earlier menopause. Animal studies show that in-utero smoke exposure is toxic to developing ovaries. Our aim was to evaluate whether in-utero smoke exposed women reach menopause earlier compared with nonexposed women.

METHODS

This is a cohort study within the Avon Longitudinal Study of Parents and Children. Participants included in this study were followed from 1991/1992 until 2010. Participant characteristics for the current analysis were obtained from obstetric records and from annual follow-up questionnaires. When not available, age at natural menopause was estimated by age at filling in the questionnaire minus 1 year. Cox proportional hazards modeling was used to estimate hazard ratios of menopause for in-utero exposed and nonexposed women.

RESULTS

There were 695/2,852 postmenopausal women, of whom 466 had natural menopause, 117 had hormonal therapy, and 112 had surgical menopause. Age at natural menopause was 50.6 ± 3.7 years. Of all participants, 20.2% (577/2,852) were exposed to smoke in-utero. Participants who were in-utero exposed but were not smokers did not have higher hazards of menopause (adjusted hazard ratio [HR] 0.92, 95% CI 0.72-1.18), whereas participants who were ever smokers (current or previous) and were in-utero exposed (adjusted HR 1.41, 95% CI 1.01-1.95) or were ever smokers but not exposed (adjusted HR 1.24, 95% CI 1.00-1.53) did have higher hazards of earlier menopause.

CONCLUSIONS

In-utero smoke exposure was not associated with earlier menopause, but the effect of in-utero smoke exposure was modified by the smoking habits of the participants themselves increasing the risk for smokers who were in-utero exposed.

Maternal cigarette smoking during pregnancy and offspring DNA methylation in midlife

Maternal smoking in pregnancy (MSP) has been associated with DNA methylation in specific CpG sites (CpGs) in infants and children. We investigated whether MSP, independent of own personal active smoking, was associated with midlife DNA methylation in CpGs that were previously identified in studies of MSP-DNA methylation in children. We used data on MSP collected from pregnant mothers of 89 adult women born in 1959-1964 and measured DNA methylation in blood (granulocytes) collected in 2001-2007 (mean age: 43 years). Seventeen CpGs were differentially methylated by MSP, with multiple CpGs mapping to CYP1A1, MYO1G, AHRR, and GFI1. These associations were consistent in direction with prior studies (e.g., MSP associated with more and less methylation in AHRR and CYP1A1, respectively) and, with the exception of AHRR CpGs, were not substantially altered by adjustment for active smoking. These preliminary results confirm prior prospective reports that MSP influences the offspring DNA methylation, and extends the timeframe to midlife, and suggest that these effects may persist into adulthood, independently of active smoking.

Factors associated with menstrual cycle irregularity and menopause

Background

A regular menstrual cycle is an important indicator of a healthy reproductive system. Previous studies reported obesity, stress, and smoking as the factors that are associated with irregular menstruation and early menopause. However, the integrative effects of these modifiable risk factors have not been fully understood. This study aimed to investigate the modifiable risk factors of menstrual cycle irregularity and premature menopause, as well as their individual and combined effects among adult women in Korea.

Method

This study selected adult women aged 19 years and above who had been included in the 2007–2014 Korean National Health and Nutrition Examination Survey. We used a separate dataset to analyze the risk factors of menstrual cycle irregularity and menopause (pre- and postmenopausal women: n = 4788 and n = 10,697, respectively). Univariate and multiple logistic regression analyses were conducted to evaluate the effects of smoking, drinking, obesity, and perceived level of stress on the menstrual cycle and menopause. Both logit and linear models were used in the analyses of the association between smoking and menopausal age. Equivalized household income, marital status, and educational level were considered as covariates. The modifiable risk factor scores were also calculated to integrate the effect of smoking, drinking, and obesity in the analysis.

Result

Results showed that smoking status, pack-year, obesity, and perceived level of stress were significantly associated with irregular menstruation among premenopausal women. Especially, women demonstrating > 3 modifiable risk factor scores had 1.7 times higher risk of having irregular menstruation than those who had a 0 score. Meanwhile, early initiation of smoking (≤19 years) and high pack-year (≥5) were also significantly associated with premature menopause among postmenopausal women.

Conclusion

This study demonstrated that modifiable risk factors, such as smoking, obesity, and stress, were significantly associated with menstrual cycle irregularity. Lifetime smoking was also correlated with early menopause. Our results suggested that healthier lifestyle practices, including, cessation of smoking, weight control, and stress management, were important factors in improving the reproductive health of women throughout life.

Environmental pollutants, a possible etiology for premature ovarian insufficiency: a narrative review of animal and human data

BACKGROUND

Because only 25% of cases of premature ovarian insufficiency (POI) have a known etiology, the aim of this review was to summarize the associations and mechanisms of the impact of the environment on this pathology. Eligible studies were selected from an electronic literature search from the PUBMED database from January 2000 to February 2016 and associated references in published studies. Search terms included ovary, follicle, oocyte, endocrine disruptor, environmental exposure, occupational exposure, environmental contaminant, pesticide, polyaromatic hydrocarbon, polychlorinated biphenyl PCB, phenol, bisphenol, flame retardant, phthalate, dioxin, phytoestrogen, tobacco, smoke, cigarette, cosmetic, xenobiotic. The literature search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We have included the human and animal studies corresponding to the terms and published in English. We have excluded articles that included results that did not concern ovarian pathology and those focused on ovarian cancer, polycystic ovary syndrome, endometriosis or precocious puberty. We have also excluded genetic, auto-immune or iatrogenic causes from our analysis. Finally, we have excluded animal data that does not concern mammals and studies based on results from in vitro culture. Data have been grouped according to the studied pollutants in order to synthetize their impact on follicular development and follicular atresia and the molecular pathways involved. Ninety-seven studies appeared to be eligible and were included in the present study, even though few directly address POI. Phthalates, bisphenol A, pesticides and tobacco were the most reported substances having a negative impact on ovarian function with an increased follicular depletion leading to an earlier age of menopause onset. These effects were found when exposure occured at different times throughout the lifetime from the prenatal to the adult period, possibly due to different mechanisms. The main mechanism seemed to be an increase in atresia of pre-antral follicles.

CONCLUSION

Environmental pollutants are probably a cause of POI. Health officials and the general public must be aware of this environmental effect in order to implement individual and global preventive actions.

Earlier age at menarche in girls with rapid early life growth: cohort and within sibling analyses

PURPOSE

The purpose of the article was to examine the association of early life growth with age at menarche.

METHODS

Using data from a prospective birth cohort (n = 1134 women, 290 sibling sets), we assessed the association between postnatal growth at 4 months, 1 year, and 4 years and age at menarche, using generalized estimating equations and generalized linear random effects models.

RESULTS

Overall, 18% of the cohort experienced early menarche (<12 years). After accounting for postnatal growth in length, faster postnatal change in weight (per 10-percentile increase) in all three periods was associated with an increase (range 9%-20%) in the likelihood of having an early menarche. In adjusted linear models, faster weight gains in infancy and childhood were associated with an average age at menarche that was 1.1-1.3 months earlier compared with stable growth. The overall results were consistent for percentile and conditional growth models. Girls who experienced rapid growth (defined as increasing across two major Centers for Disease Control and Prevention growth percentiles) in early infancy had an average age at menarche that was 4.6 months earlier than girls whose growth was stable.

CONCLUSIONS

Faster postnatal weight gains in infancy and early childhood before the age of 4 years are associated with earlier age at menarche.

Early life socioeconomic environment and mammographic breast density

Background

Early life social environment may influence breast cancer through shaping risk factors operating in early life, adolescence and adulthood, or may be associated with breast cancer risk independent of known risk factors. We investigated the associations between early life socioeconomic status (SES) and mammographic density, a strong risk factor for breast cancer, and the extent to which these associations were independent of risk factors across the lifecourse.

Methods

We used data from an adult follow-up study of two U.S. birth cohorts of women (average age = 43 years) with prospectively collected data starting during the pregnancy of the mother and continuing through early childhood of the offspring. We collected data on factors in later life periods through computer-assisted interviews with the offspring as adults, and obtained routine clinical mammograms for measurement of percent density and dense and nondense breast areas using a computer assisted method. We used generalized estimating equation models for multivariable analysis to account for correlated data for sibling sets within the study sample (n = 700 composed of 441 individuals and 127 sibling sets).

Results

Highest vs. lowest family income level around the time of birth was associated with smaller dense breast area after adjustment for early life factors (e.g., birthweight, maternal smoking during pregnancy) and risk factors in later life periods, including adult body mass index (BMI) and adult SES (β = −8.2 cm², 95% confidence interval [CI]: −13.3, −3.2). Highest vs. lowest parental educational attainment was associated with higher percent density in models that adjusted for age at mammogram and adult BMI (e.g., β = 4.8, 95% CI = 0.6, 9.1 for maternal education of college or higher degree vs. less than high school), but the association was attenuated and no longer statistically significant after further adjustment for early life factors. There were no associations between early life SES indicators and non-dense area after adjustment for adult BMI. Neither adult education nor adult income was statistically significantly associated with any measure of mammographic density after adjusting for age and adult BMI.

Conclusions

We did not observe consistent associations between different measures of early life SES and mammographic density in adulthood.

Menopausal Age and Chronic Diseases in Elderly Women: A Cross-Sectional Study in Northeast China

Many factors affect menopausal age, and early or late onset of menopause may be associated with many chronic health problems. However, limited data are available regarding this phenomenon in the Northeast China population. For this study, 2011 elderly women were selected as a sample from participants in a cross-sectional survey performed using stratified, clustered multistage, and random sampling methods. Early menopause was more prevalent in subjects born from 1943 to 1947 (OR = 1.708, 95% CI = 1.205, 2.420) and 1933 to 1937 (OR = 2.445, 95% CI: 1.525, 3.921) and in physical laborers (OR = 1.413, 95% CI = 1.021, 1.957). Women with less than nine years of education (OR = 0.515, 95% CI: 0.327, 0.812) and who were current smokers (OR = 0.577, 95% CI: 0.347, 0.959) were less likely to have late menopause. BMIs between 25 and 30 (OR = 1.565, 95% CI: 1.152, 2.125) and greater than 30 (OR = 2.440, 95% CI: 1.482, 4.016) were associated with later menopausal age. Late menopause was positively associated with diabetes (OR = 1.611, 95% CI: 1.142, 2.274) but protective against chronic gastroenteritis/peptic ulcers (OR = 0.533, 95% CI: 0.333, 0.855). Results showed that (1) Being born in an earlier year, having a lower education, and engaging in physical labor were associated with an earlier menopausal age, while a higher BMI was associated with a later menopausal age; and that (2) menopausal age was associated with diabetes and gastroenteritis in elderly women living in Northeast China.

Smoking, alcohol and caffeine in relation to two hormonal indicators of ovarian age during the reproductive years

OBJECTIVE

To examine whether or not cigarette smoking, alcohol and caffeine intake are related to two indicators of ovarian age-anti-Müllerian hormone (AMH) and follicle stimulating hormone (FSH).

STUDY DESIGN

Cross-sectional study of 477 women with a recent index spontaneous abortion (SA) (105 trisomic, 93 non-trisomic) or livebirth (LB) (279) with hormones measured on days 2-4 of an apparently normal menstrual cycle after the index pregnancy.

RESULTS

Current smoking is associated with about a 15% increase in median FSH (β for ln(FSH)=0.14, 95% CI 0.03,0.25). It is not significantly related to AMH (β for ln(AMH)=-0.25, 95% CI -0.56,0.06). Neither alcohol 2-7days per week nor caffeine 122-<553mg per day is independently related to AMH or FSH.

CONCLUSIONS

The observation that current smoking is associated with FSH, but not with AMH, suggests that current smoking either impairs the development of antral follicles or dysregulates the hypothalamic-pituitary-ovarian axis. The absence of an association with AMH argues against mechanisms related to accelerated follicle atresia.

A fetal whole ovarian culture model for the evaluation of CrVI-induced developmental toxicity during germ cell nest breakdown

Prenatal exposure to endocrine disrupting chemicals (EDCs), including bisphenol A, dioxin, pesticides, and cigarette smoke, has been linked to several ovarian diseases such as premature ovarian failure (POF) and early menopause in women. Hexavalent chromium (CrVI), one of the more toxic heavy metals, is widely used in more than 50 industries. As one of the world's leading producers of Cr compounds, the U.S. is facing growing challenges in protecting human health against adverse effects of CrVI. Our recent findings demonstrated that in vivo CrVI exposure during gestational period caused POF in F1 offspring. Our current research focus is three-fold: (i) to identify the effect of CrVI on critical windows of great vulnerability of fetal ovarian development; (ii) to understand the molecular mechanism of CrVI-induced POF; (iii) to identify potential intervention strategies to mitigate or inhibit CrVI effects. In order to accomplish these goals we used a fetal whole ovarian culture system. Fetuses were removed from the normal pregnant rats on gestational day 13.5. Fetal ovaries were cultured in vitro for 12 days, and treated with or without 0.1 ppm potassium dichromate (CrVI) from culture day 2-8, which recapitulated embryonic day 14.5-20.5, in vivo. Results showed that CrVI increased germ cell/oocyte apoptosis by increasing caspase 3, BAX, p53 and PUMA; decreasing BCL2, BMP15, GDF9 and cKIT; and altering cell cycle regulatory genes and proteins. This model system may serve as a potential tool for high throughput testing of various drugs and/or EDCs in particular to assess developmental toxicity of the ovary.