Association between duration of endogenous estrogen exposure and cardiovascular outcomes: A population - based cohort study

Endogenous Estrogen Exposure and Hypertension Risk; A Population-based Cohort Study With About 2 Decades of Follow-up

CONTENT

The impact of endogenous estrogen exposure (EEE) on hypertension (HTN) incidence has not been investigated yet.

OBJECTIVE

This study aimed to evaluate HTN incidence in women with different endogenous estrogen durations.

METHODS

Information was gathered from the Tehran Lipid and Glucose Study to conduct current research. At the initiation of the study, 4463 postmenarche normotensive women, including 3599 premenopausal and 864 menopausal women, were included. EEE was calculated for each woman, and they were followed up for the HTN event. According to the EEE, the hazard ratios and 95% confidence intervals (CI) for the HTN event were presented using Cox proportional hazards regression models (unadjusted and adjusted).

RESULTS

The median (interquartile range) of follow-up (between menarche and the date of HTN incidence or last follow-up) was 33.2 (25.1, 42.3) years. The event of menopause occurred in 31.8% of participants. The unadjusted model's findings illustrated that the EEE z-score was inversely associated with HTN incidence in postmenarcheal women [unadjusted hazard ratio (HR) .47, 95% CI .44-.50], meaning that the risk of HTN decreased by 53% for every 1-SD rise in the EEE z-score. After adjusting for potential confounders, the results showed no statistically significant changes (adjusted HR .46, 95% CI .43-.49). In participants with prehypertension at baseline, the hazard of HTN decreased by 56% per 1-SD rise in the EEE z-score.

CONCLUSION

This longitudinal study demonstrated the protective effect of a longer EEE duration on HTN risk, even among those with prehypertension status.

Association between lifetime endogenous estrogen exposure and body composition metrics in postmenopausal women: findings from the Tehran Lipid and Glucose Study

BACKGROUND

The role of endogenous estrogen exposure (EEE) in shaping body composition and its implications for cardiometabolic health remain understudied despite its potential significance. This cross-sectional study aimed to investigate the association between EEE and body composition indices among postmenopausal women.

METHODS

Data were obtained from the Tehran Lipid and Glucose Study (TLGS), including 960 women aged over 40 years. EEE was calculated based on reproductive events, and participants were categorized into tertiles. Anthropometric measurements and body composition were assessed using standardized protocols. Linear regression models were employed to evaluate associations, adjusting for potential confounders.

RESULTS

It was revealed significant differences in body composition indices across EEE tertiles, with increasing EEE associated with decreased fat mass, skeletal muscle mass, and fat-free mass. Moreover, women with higher EEE exhibited lower anthropometric and body composition measurements compared to those with lower EEE, even after adjusting for confounding factors. Specifically, for each year of increasing EEE, fat mass decreased by 0.12 kg, skeletal muscle mass by 0.04 kg, fat-free mass by 0.07 kg, and fat mass ratio decreased by 0.003. Comparing tertiles, women with the highest EEE demonstrated significantly lower anthropometric and body composition measurements compared to those with the lowest EEE.

CONCLUSION

These findings suggest a link between EEE and favorable changes in body composition, highlighting the importance of considering reproductive history in health assessment.

Lifetime cumulative effect of reproductive factors on ischaemic heart disease in a prospective cohort

OBJECTIVE

This study aimed to examine the association between lifetime oestrogen exposure and ischaemic heart disease (IHD), based on the hypothesis that higher lifetime oestrogen exposure is linked to lower cardiovascular risk.

METHODS

In 2004-2008, lifetime cumulative exposure to reproductive factors was assessed among postmenopausal females from the China Kadoorie Biobank using reproductive lifespan (RLS), endogenous oestrogen exposure (EEE) and total oestrogen exposure (TEE). EEE was calculated by subtracting pregnancy-related and contraceptive use duration from RLS, while TEE by adding up the same components except for lactation. Incident IHD during follow-up (2004-2015) was identified. Stratified Cox proportional hazards models estimated the HRs and 95% CIs of IHD for RLS, EEE and TEE.

RESULTS

Among 118 855 postmenopausal females, 13 162 (11.1%) developed IHD during a median follow-up of 8.9 years. The IHD incidence rates were 13.0, 12.1, 12.5, 13.8 per 1000 person-years for RLS Q1-Q4, 15.8, 12.6, 11.3, 12.1 per 1000 person-years for EEE Q1-Q4 and 13.7, 12.3, 12.2, 13.4 per 1000 person-years for TEE Q1-Q4. The highest quartile (Q4) of RLS and TEE were associated with lower risks of IHD (adjusted HR (aHR) 0.95, 95% CI 0.91 to 1.00 and 0.92, 95% CI 0.88 to 0.97, respectively) compared with the lowest quartile (Q1). Longer EEE showed progressively lower risks of incident IHD (aHR 0.93, 95% CI 0.88 to 0.97; 0.88, 95% CI 0.84 to 0.93; 0.87, 95% CI 0.83 to 0.92 for Q2-Q4 vs Q1).

CONCLUSIONS

Longer RLS, TEE and EEE were associated with lower risks of IHD among Chinese postmenopausal females.

The association between arterial hypertension and menarcheal age

OBJECTIVE

Menarche, as a milestone of puberty, may have a long-term effect on health. The present study investigated the association of age at menarche with the incidence of arterial hypertension.

STUDY DESIGN

A total of 4747 post-menarcheal participants of the Tehran Lipid and Glucose Study who met the eligibility criteria were selected. Demographic, lifestyle, reproductive, and anthropometric data, as well as risk factors for cardiovascular diseases, were collected. Participants were classified according to their age at menarche: group I: ≤11 years, group II: 12-15 years, and group III: ≥16 years.

MAIN OUTCOME MEASURES

A Cox proportional hazards regression model was used to estimate the associations between age at menarche and arterial hypertension outcomes. The generalized estimating equation models were used to compare the trend of changes in systolic and diastolic blood pressure between the three groups.

RESULTS

The mean age of participants at baseline was 33.9 (13.0). At the end of the study, 1261 (26.6 %) participants had arterial hypertension. Women in group III had a 2.04-fold higher risk of arterial hypertension than those in group II. The mean changes in systolic and diastolic blood pressure were 29 % (95 % CI: 0.02-0.57) and 16 % (95 % CI: 0.00-0.38) higher for women in group III compared with group II.

CONCLUSIONS

Late menarche could be a risk factor for arterial hypertension, so it is necessary to pay more attention to age at menarche in cardiovascular risk assessment programs.

Menopausal hormone therapy and the risk of type 2 diabetes mellitus: Health Insurance Database in South Korea-based retrospective cohort study

OBJECTIVE

Menopausal hormone therapy (MHT) is known to reduce the incidence of type 2 diabetes mellitus (T2DM); however, since the Women's Health Initiative study, the types and doses of female hormones used for MHT have changed considerably. Therefore, this study was conducted to determine whether MHT, which is currently widely prescribed, increases the risk of T2DM.

METHOD

We performed a retrospective cohort study based on national health insurance data and cancer screening data from 2002 to 2019. We included the MHT group as postmenopausal women older than 40 years who used at least one MHT for at least 6 months between 2003 and 2011. We subclassified the MHT group into five categories; tibolone, combined estrogen plus progestin by the manufacturer (CEPM), oral estrogen, combined estrogen plus progestin by the physician (CEPP), and transdermal estrogen. We selected the non-MHT group as postmenopausal women who had never been prescribed MHT from 2002 to 2019. We compared the incidence of T2DM between the MHT group and the non-MHT group.

RESULTS

We enrolled 330,771 women in the MHT group and 798,550 women in the control group. T2DM was diagnosed in 15.2% of the non-MHT group, 16.6% of the tibolone group, 12.1% of the CEPM group, 16.6% of the oral estrogen group, 15.4% of the CEPP group, and 17% of the transdermal estrogen group. In Cox proportional hazard analysis adjusted for variable factors, tibolone, oral estrogen, CEPP, and transdermal estrogen increased the incidence of T2DM. In contrast, there was no change in the risk of T2DM in the CEPM group.

CONCLUSIONS

MHT, including tibolone, which is currently the most prescribed agent, increased the risk of T2DM; however, CEPM did not increase the risk of T2DM. Only tibolone increased the risk of T2DM in participants older than 70 years.

The Impact of Endogenous Estrogen Exposure Duration on Fracture Incidence: a Longitudinal Cohort Study

CONTEXT

Although it is well documented that estrogen hormone is positively associated with bone mineral density and lower risk of fracture, there are limited studies on the association between duration of endogenous estrogen exposure (EEE) and fracture, especially by longitudinal design.

OBJECTIVE

This study aimed to investigate the relationship between EEE with fracture incidence by longitudinal design in a community-based study.

METHODS

A total of 5269 eligible postmenarcheal women, including 2411 premenopausal and 2858 menopausal women, were recruited from among the Tehran Lipid and Glucose Study. Cox proportional hazards regression model with adjustment of potential confounders was performed to assess the relationship between duration of EEE and incident of any hospitalized fractures.

RESULTS

A total of 26.7% (1409/5269) women were menopausal at the baseline, and 2858 of the remaining participants reached menopause at the end of follow-up. Results of the unadjusted model demonstrated that the EEE z-score was negatively associated with fracture incidence [unadjusted hazard ratio (HR) 0.81, 95% CI 0.68-0.96] in postmenarchal women, indicating that per 1-SD increase of EEE z-score, the hazard of fracture reduced by 19%. Results remained statistically unchanged after adjustment for potential confounders (adjusted HR 0.70, 95% CI 0.58-0.86).

CONCLUSION

The findings of this cohort study suggest that a longer duration of EEE has a protective effect on fracture incidence; a point that needs to be considered in fracture risk assessment.

Aging and changes in adiposity indices: the impact of menopause

PURPOSE

Aging is associated with significant changes in fat distribution and menopause may alter this process. This study aimed to investigate the longitudinal effect of menopause on changes in adiposity indices (AI).

METHODS

A total number of 3876 non-menopausal women, aged > 20 years, who participated in the Tehran Lipid and Glucose study, were selected for the present study. They were followed from 1998 to 2018 at a 3-year interval and their adiposity indices were measured. Throughout the study, participants were categorized into two groups according to their menopausal status as group 1): women who reached menopause and group 2): women who did not reach menopause. The generalized estimation equation (GEE) models were used to compare the trend of changes in AIs between these two groups.

RESULTS

At the end of the study, a total number of 1479 (38.2%) participants reached menopause. The odds of general obesity decreased by 5% (OR: 0.95, 95% CI: 0.90-0.99), and the odds of central obesity increased by 6% in group1 compared to group2 (OR: 1.06, 95% CI: 1.01-1.12).

CONCLUSIONS

Menopause alters the impact of aging on central fat distribution. Increasing awareness of the related risk in menopausal women and their healthcare professional may prevent adverse related outcomes.

Effects of menopausal hormone therapy on cardiovascular diseases and type 2 diabetes in middle-aged postmenopausal women: analysis of the Korea National Health Insurance Service Database

OBJECTIVE

Although menopausal hormone therapy (MHT) is the most effective treatment for menopausal symptoms, menopausal women hesitate to start MHT due to concerns about adverse events. Recently, however, it has been recommended to use it for appropriate patients who have been evaluated for baseline diseases, age, and timing of initiation. We aimed to investigate the association of MHT with cardiovascular diseases (CVDs) and type 2 diabetes among middle-aged postmenopausal women in Korea.

METHODS

Data were collected from the National Health Insurance Service database in Korea from 2002 to 2016. A total of 58,060 postmenopausal women (including 8,013 [13.8%] MHT users and 50,047 [86.2%] nonusers) were included. The time-dependent Cox regression model with a 1-year latency period was used to evaluate the hazard ratio (HR) and 95% confidence interval (CI) of the associations of MHT with CVDs and type 2 diabetes outcomes. Subgroup analyses by regimen type and cumulative duration were conducted.

RESULTS

In the multivariate-adjusted model, MHT was not significantly associated with CVDs (HR = 1.085, 95% CI: 0.899-1.310) or type 2 diabetes (HR = 1.104, 95% CI: 0.998-1.221). Differential effects were not observed by regimen type, cumulative duration, and years since menopause subgroups. Sensitivity analyses also did not show adverse events by MHT on CVDs and type 2 diabetes.

CONCLUSIONS

Although protective effects of MHT against CVDs or type 2 diabetes were not observed among postmenopausal women who had screened underlying diseases, our results may contribute to reducing the current concerns about the use of MHT for middle-aged postmenopausal women in Korea.

Endogenous estrogen exposure and chronic kidney disease; a 15-year prospective cohort study

BACKGROUND

Despite strong evidence demonstrating the role of estrogen as a protective factor for kidney function in women, limited data are available regarding the influence of endogenous estrogen exposure (EEE) on chronic kidney disease (CKD). The present study aimed to assess the incidence of CKD in women with various levels of EEE.

METHODS

In a prospective population-based study over a 15-year follow-up, a total of 3043 eligible women aged 30-70 years, participating in Tehran-Lipid and Glucose-Study were recruited and divided into two groups (EEE < 11 and EEE ≥ 11 years). EEE calculated based on age at menarche, age at menopause, number and duration of pregnancies, lactation, and duration of oral contraceptive use after excluding the progesterone dominant phase of the menstrual cycle. Cox's proportional hazards model was applied to estimate the hazard ratio of CKD between the study groups, after adjusting for confounders.

RESULTS

The total cumulative incidence rate of CKD was 50.1 per 1000 person years; 95% CI: 47.7-52.6); this was 53.9 (95%CI, 50.2-57.8) and 47.1 (95%CI, 44.0-50.4) per 1000 person years in women with EEE < 11 and EEE ≥ 11 years, respectively. The model adjusted for age, BMI, smoking, hypertension, and diabetes showed that the hazard ratio (HR) of incidence CKD in women with EEE < 11 compare to those with EEE ≥ 11 years in the subgroup of women aged< 45 years was 2.66(95% CI, 2.2, 3.2), whereas, in the subgroup aged ≥45 years, it was 1.22 (95% CI, 1.04, 1.4).

CONCLUSION

This study shows a higher HR of CKD incidence in women with low EEE levels in their later life. Screening of these women for CKD may be recommended.

Duration of estrogen exposure during reproductive years, age at menarche and age at menopause, and risk of cardiovascular disease events, all-cause and cardiovascular mortality: a systematic review and meta-analysis

BACKGROUND

Little is known about the estrogen exposure measurement and mutual effect of age at menarche and age at menopause in the risk of cardiovascular disease (CVD) events.

OBJECTIVES

To evaluate estrogen exposure measurement and describe mutual effect of age at menarche and age at menopause in the risk of CVD events.

SEARCH STRATEGY

Systematic review of literature in PubMed, Embase and Web of Science for studies published up to 28 June 2020.

SELECTION CRITERIA

Observational studies related to estrogen exposure measurement, including mutual effect of age at menarche and age at menopause and risk of CVD events.

DATA COLLECTION AND ANALYSIS

Synthesis of evidence was conducted by reviewing individual estimates, followed by meta-analysis. The study received no external funding.

MAIN RESULTS

A total of 75 studies were included in synthesis of evidence, of which 17 studies were included in meta-analysis. Reproductive lifespan (age at menopause - age at menarche), endogenous estrogen exposure and total estrogen exposure were used for estrogen exposure measurement. Reproductive lifespan was by far the most commonly used method for estrogen exposure measurement. A shorter reproductive lifespan was associated with a higher risk of CVD events; the pooled relative risk (95% CI) was 1.31 (1.25-1.36) for stroke events. Robust epidemiological studies with measurement of estrogen exposure and associated health risk would strengthen the evidence.

CONCLUSIONS

Reproductive lifespan was the most commonly used method for estrogen exposure measurement in epidemiological studies. A shorter reproductive lifespan was associated with a higher risk of CVD events, particularly stroke.

TWEETABLE ABSTRACT

A systematic review and meta-analysis found that women with a shorter reproductive lifespan have a higher risk of stroke events.

Estrogen Receptors and Ubiquitin Proteasome System: Mutual Regulation

This review provides information on the structure of estrogen receptors (ERs), their localization and functions in mammalian cells. Additionally, the structure of proteasomes and mechanisms of protein ubiquitination and cleavage are described. According to the modern concept, the ubiquitin proteasome system (UPS) is involved in the regulation of the activity of ERs in several ways. First, UPS performs the ubiquitination of ERs with a change in their functional activity. Second, UPS degrades ERs and their transcriptional regulators. Third, UPS affects the expression of ER genes. In addition, the opportunity of the regulation of proteasome functioning by ERs—in particular, the expression of immune proteasomes—is discussed. Understanding the complex mechanisms underlying the regulation of ERs and proteasomes has great prospects for the development of new therapeutic agents that can make a significant contribution to the treatment of diseases associated with the impaired function of these biomolecules.

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.