Parity and Cardiovascular Disease Mortality: a Dose-Response Meta-Analysis of Cohort Studies

Normotensive placental extracellular vesicles provide long-term protection against hypertension and cardiovascular disease

BACKGROUND

Women with normotensive pregnancy are at a reduced risk of developing cardiovascular disease postpartum compared with those who experience hypertensive conditions during pregnancy. However, the underlying mechanisms remain poorly understood. During normotensive pregnancy, vast numbers of placental extracellular vesicles are released into the maternal circulation, which protect endothelial cells from activation and alter maternal vascular tone. We hypothesized that placental extracellular vesicles play a mechanistic role in lowering the risk of cardiovascular disease following normotensive pregnancy.

OBJECTIVE

This study aimed to investigate the long-term effects of placental extracellular vesicles derived from normotensive term placentae on the cardiovascular system and explore the mechanisms underlying their biological effects.

STUDY DESIGN

Spontaneously hypertensive rats were injected with placental extracellular vesicles from normotensive term pregnancies (2 mg/kg each time, n=8) or vehicle control (n=9) at 3 months of age. Blood pressure and cardiac function were regularly monitored from 3 months to 15 months of age. The response of mesenteric resistance arteries to vasoactive substances was investigated to evaluate vascular function. Cardiac remodeling, small artery remodeling, and renal function were investigated to comprehensively assess the impact of placental extracellular vesicles on cardiovascular and renal health.

RESULTS

Compared with vehicle-treated control animals, rats treated with normotensive placental extracellular vesicles exhibited a significantly lower increase in blood pressure and improved cardiac function. Furthermore, the vasodilator response to the endothelium-dependent agonist acetylcholine was significantly enhanced in the normotensive placental extracellular vesicle-treated spontaneously hypertensive rats compared with the control. Moreover, treatment with placental extracellular vesicles reduced wall thickening of small renal vessels and attenuated renal fibrosis.

CONCLUSION

Placental extracellular vesicles from normotensive term pregnancies have long-lasting protective effects reducing hypertension and mitigating cardiovascular damage in vivo.

Reproductive factors and cardiometabolic disease among middle-aged and older women: a nationwide study from CHARLS

Background

Cardiometabolic disease is skyrocketing to epidemic proportions due to the high prevalence of its components and the aging of the worldwide population. More efforts are needed to improve cardiometabolic health. The aim of this nationally representative study based on the China Health and Retirement Longitudinal Study (CHARLS, 2014-2018) was to examine the association between reproductive factors and cardiometabolic disease among Chinese women aged ≥45 years.

Methods

The CHARLS is an ongoing longitudinal study initiated in 2011, and the latest follow-up was completed in 2018. In total, 6,407 participants were analyzed. Effect-sizes are expressed as odds ratios (OR) and 95% confidence intervals (CI). Confounding was considered from statistical adjustment, subsidiary exploration, and unmeasured confounding assessment aspects.

Results

Of 6,407 accessible participants, 60.9% were recorded as having one or more of five predefined cardiovascular or metabolic disorders. Compared to those with two children, participants who had 0-1 child were found to have a lower risk of cardiometabolic disease (OR = 0.844, 95% CI: 0.714-0.998), and those who had ≥3 children had a greater risk (OR = 1.181, 95% CI: 1.027-1.357). Age at menarche of 16-18 years was a protective factor compared with ≤16 years of age (OR = 0.858, 95% CI: 0.749-0.982). In contrast, participants with a history of abortion were 1.212 times more likely to have cardiometabolic disorders (OR = 1.212, 95% CI: 1.006-1.465). The likelihood for the presence of unmeasured confounding was low, as reflected by E-values.

Conclusions

Our findings demonstrate that number of children, age at menarche, and history of abortion were associated with a significant risk of cardiometabolic disease among Chinese women aged ≥45 years.

Pregnancy is linked to faster epigenetic aging in young women

A central prediction of evolutionary theory is that energy invested into reproduction comes at the expense of somatic maintenance and repair, accelerating biological aging. Supporting this prediction are findings that high fertility among women predicts shorter lifespan and poorer health later in life. However, biological aging is thought to begin before age-related health declines, limiting the applicability of morbidity and mortality for studying the aging process earlier in life. Here, we examine the relationship between reproductive history and biological aging in a sample of young (20 to 22yo) men and women from the Cebu Longitudinal Health and Nutrition Survey, located in the Philippines (n = 1,735). We quantify biological aging using six measures, collectively known as epigenetic clocks, reflecting various facets of cellular aging, health, and mortality risk. In a subset of women, we test whether longitudinal changes in gravidity between young and early-middle adulthood (25 to 31yo) are associated with changes in epigenetic aging during that time. Cross-sectionally, gravidity was associated with all six measures of accelerated epigenetic aging in women (n = 825). Furthermore, longitudinal increases in gravidity were linked to accelerated epigenetic aging in two epigenetic clocks (n = 331). In contrast, the number of pregnancies a man reported fathering was not associated with epigenetic aging among same-aged cohort men (n = 910). These effects were robust to socioecological, environmental, and immunological factors, consistent with the hypothesis that pregnancy accelerates biological aging and that these effects can be detected in young women in a high-fertility context.

The Importance of Nontraditional and Sex-Specific Risk Factors in Young Women With Vasomotor Nonobstructive vs Obstructive Coronary Syndromes

Background

Heart disease is the leading cause of premature death for women in Canada. Ischemic heart disease is categorized as myocardial infarction (MI) with no obstructive coronary artery disease (MINOCA), ischemia with no obstructive coronary arteries (INOCA), and atherosclerotic obstructive coronary artery disease (CAD) with MI (MI-CAD) or without MI (non-MI-CAD). This study aims to study the prevalence of traditional and nontraditional ischemic heart disease risk factors and their relationships with (M)INOCA, compared to MI-CAD and non-MI-CAD in young women.

Methods

This study investigated women who presented with premature (at age ≤ 55 years) vasomotor entities of (M)INOCA or obstructive CAD confirmed by coronary angiography, who are currently enrolled in either the Leslie Diamond Women's Heart Health Clinic Registry (WHC) or the Study to Avoid Cardiovascular Events in British Columbia (SAVEBC). Univariable and multivariable regression models were applied to investigate associations of risk factors with odds of (M)INOCA, MI-CAD, and non-MI-CAD.

Results

A total of 254 women enrolled between 2015 and 2022 were analyzed, as follows: 77 with INOCA and 37 with MINOCA from the registry, and 66 with non-MI-CAD and 74 with MI-CAD from the study. Regression analyses demonstrated that migraines and preeclampsia or gestational hypertension were the most significant risk factors, with a higher likelihood of being associated with premature (M)INOCA, relative to obstructive CAD. Conversely, the presence of diabetes and a current or previous smoking history had the highest likelihood of being associated with premature CAD.

Conclusions

The risk factor profiles of patients with premature (M)INOCA, compared to obstructive CAD, have significant differences.

Are pregnancy and parity associated with telomere length? A systematic review

BACKGROUND

Women's reproduction requires increased energy demands, which consequently may lead to cellular damage and aging. Hence, Telomere Length (TL), a biomarker of biological aging and health status may possibly serve as a biomarker of reproductive effort. The aim of this systematic review is to evaluate telomere dynamics throughout pregnancy and the association between parity and TL.

METHODS

A systematic search was conducted across seven databases including CINAHL, Cochrane, PsycINFO, Proquest, PubMed; Scopus; and Web of Science, using keywords and MeSH descriptors of parity and TL. Predefined inclusion and exclusion criteria were used to screen abstracts and titles. After the removal of duplicates, 3431 articles were included in the primary screening, narrowed to 194 articles included in the full-text screening. Consensus was reached for the 14 studies that were included in the final review, and the Newcastle-Ottawa scale (NOS) was utilized to assess the quality of the selected studies. A mini meta-analysis utilized JASP 0.17.3 software and included 4 applicable studies, comprising a total of 2564 participants to quantitatively assess the estimated effect size of parity on TL.

RESULTS

Of the 11 studies reviewed on parity and TL, four demonstrated a negative correlation; one - a positive correlation and six -found no correlation. Studies demonstrating a negative correlation encompassed rigorous methodological practices possibly suggesting having more children is associated with enhanced telomere attrition. Of the four longitudinal studies assessing telomere dynamics throughout pregnancy, most found no change in TL from early pregnancy to postpartum suggesting pregnancy does not affect TL from early pregnancy to early postpartum. The meta-analysis revealed a negative, yet, non-significant effect, of the estimated effect size of parity on TL(ES = -0.009, p = 0.126, CI -0.021, 0.03).

CONCLUSIONS

Studies assessing pregnancy, parity and TL yielded mixed results, most likely due to the different research methods utilized in each study. Improvements in study design to better understand the short-term effects of pregnancy on TL and the effect of parity on TL over time, include precise definitions of parity, comparisons of different age groups, inclusion of reproductive lifespan and statistically adjusting for potential confounders in the parity and TL relationship.

Female Reproductive Events and Subclinical Atherosclerosis of the Brain and Carotid Arteriopathy: the Ohasama Study

AIMS

Few studies have investigated the subclinical atherosclerotic changes in the brain and carotid artery, and in East Asian populations. We sought to investigate whether gravidity, delivery, the age at menarche and menopause and estrogen exposure period are associated with subclinical atherosclerosis of the brain and carotid arteriopathy.

METHODS

This cross-sectional study formed part of a cohort study of Ohasama residents initiated in 1986. Brain atherosclerosis and carotid arteriopathy were diagnosed as white matter hyperintensity (WMH) and lacunae evident on brain magnetic resonance imaging (MRI) and carotid intimal media thickness (IMT) or plaque revealed by ultrasound, respectively. The effect of the reproductive events on brain atherosclerosis and carotid arteriopathy was investigated using logistic regression and general linear regression models after adjusting for covariates.

RESULTS

Among 966 women aged ≥ 55 years in 1998, we identified 622 and 711 women (mean age: 69.2 and 69.7 years, respectively) who underwent either MRI or carotid ultrasound between 1992-2008 or 1993-2018, respectively. The highest quartile of gravidity (≥ 5 vs. 3) and delivery (≥ 4 vs. 2), and the highest and second highest (3 vs. 2) quartiles of delivery were associated with an increased risk of WMH and carotid artery plaque, respectively. Neither of age at menarche, menopause, and estrogen exposure period estimated by subtracting age at menarche from age at menopause was associated with atherosclerotic changes of brain and carotid arteries.

CONCLUSIONS

Higher gravidity and delivery are associated with subclinical atherosclerosis of the brain and carotid plaque.

Impact of Adverse Gestational Milieu on Maternal Cardiovascular Health

Cardiovascular disease affects 1% to 4% of the nearly 4 million pregnancies in the United States each year and is the primary cause of pregnancy-related mortality. Adverse pregnancy outcomes are associated with cardiovascular complications during pregnancy persisting into the postpartum period. Recently, investigations have identified an altered sex hormone milieu, such as in the case of hyperandrogenism, as a causative factor in the development of gestational cardiovascular dysfunction. The mechanisms involved in the development of cardiovascular disease in postpartum women are largely unknown. Animal studies have attempted to recapitulate adverse pregnancy outcomes to investigate causal relationships and molecular underpinnings of adverse gestational cardiac events and progression to the development of cardiovascular disease postpartum. This review will focus on summarizing clinical and animal studies detailing the impact of adverse pregnancy outcomes, including preeclampsia, gestational diabetes mellitus, and maternal obesity, on gestational cardiometabolic dysfunction and postpartum cardiovascular disease. Specifically, we will highlight the adverse impact of gestational hyperandrogenism and its potential to serve as a biomarker for maternal gestational and postpartum cardiovascular dysfunctions.

Exploring the associations between number of children, multi-partner fertility and risk of obesity at midlife: Findings from the 1970 British Cohort Study (BCS70)

BACKGROUND

Early parenthood, high parity, and partnership separation are associated with obesity. However, the emergence of non-marital partnerships, serial partnering and childbearing across unions, means that it is important to consider their association to obesity. This paper examined the associations between number of biological children and multi-partner fertility (MPF)-defined as having biological children with more than one partner, with obesity at midlife.

METHOD

The sample consisted of 2940 fathers and 3369 mothers in the 1970 British Cohort Study. The outcome was obesity (BMI 30 or over) at age 46. Fertility and partnership histories ascertained the number of live biological children and MPF status by age 42. The associations were tested using logistic regression adjusting for confounders at birth, age 10 and age 16. Adult factors recorded at age 42 including age at first birth, smoking status, alcohol dependency, educational attainment and housing tenure were considered as mediators.

RESULTS

For fathers, obesity odds did not differ according to number of children or MPF. In unadjusted models, mothers with one child (OR 1.24 95%CI 1.01-1.51), mothers who had two children with two partners (OR 1.45 95%CI 1.05-1.99), and mothers who had three or more children with two or more partners (OR 1.51 95%CI 1.18-1.93) had higher odds of obesity. In adjusted models, there remained an association between mothers with one child and odds of obesity (OR 1.30 95%CI 1.05-1.60). All other associations were attenuated when confounders were included.

CONCLUSIONS

Mothers who had children with multiple partners had higher odds of obesity. However this association was completely attenuated when parental and child confounders were accounted for; suggesting that this association may be explained by confounding. Mothers who had one child only may be at increased odds of obesity, however this could be due to multiple factors including age at first birth.

Coronary artery restenosis and target lesion revascularisation in women by pregnancy history

BACKGROUND

Women's pregnancy history is associated with incident risk of coronary artery disease with some evidence also suggesting a relevance for prognosis following treatment.

OBJECTIVES

To study the associations between maternal history of preterm delivery, a history of small for gestational age infant, parity and age at first delivery with clinical restenosis after percutaneous coronary intervention (PCI).

METHODS

In this prospective cohort study, we included 6027 women <65 years undergoing their first PCI 2006-2017, merging clinical register data on PCI procedures in Sweden with comprehensive registry data on deliveries since 1973. We used proportional hazards regression to study the association between aspects of pregnancy history and clinical restenosis in per-segment analyses, and with target lesion revascularisation (TLR) in per-patient analyses. We adjusted models for procedural-related and patient-related predictors of restenosis.

RESULTS

During 15 981 segment-years of follow-up, 343 (3.7%) events of clinical restenosis occurred. We found no strong evidence of associations between the studied aspects of pregnancy history and clinical restenosis following PCI. For example, the restenosis HR for a history of preterm delivery in the fully adjusted model was 1.09 (95% CI 0.77 to 1.55) and the TLR HR was 1.18 (95% CI 0.91 to 1.52).

CONCLUSION

Risk of restenosis following treatment with PCI did not differ by the studied aspects of pregnancy history, including preterm delivery, in young and middle-aged women. Larger studies are needed to obtain more precise estimates.

Super-additive associations between parity and education level on mortality from cardiovascular disease and other causes: the Japan Collaborative Cohort Study

Background

While women’s parity status and education level have independent associations with cardiovascular and other diseases, no studies have evaluated the additive interaction of these two factors. Therefore, we examined the additive interaction between parity and education level on mortality from stroke, coronary heart disease, total cardiovascular disease, cancer, non-cardiovascular disease, and non-cancer causes, and all causes in Japanese women.

Methods

This study followed 41,242 women aged 40–79 years without a history of cardiovascular disease or cancer from 1988 to 1990 until 2009. Baseline parity and education level were classified into four categories, with highly educated parous women as the reference group. Cox proportional hazards regression analyses were performed to calculate the risk of mortality. We also assessed the additive interactions between parity and education level on mortality from cardiovascular disease and other causes using the relative excess risk due to interaction obtained using Cox models.

Results

During the median follow-up period of 19.1 years, we identified 6299 deaths. In a multivariable model adjusted for cardiovascular disease and other disease risk factors, nulliparous women with low education levels had increased multivariable-adjusted hazard ratios of 1.67 (95% confidence interval [CI] 1.13, 2.47) for stroke, 1.98 (95% CI 1.15, 3.39) for coronary heart disease, 1.71 (95% CI 1.34,2.18) for total cardiovascular disease, 1.69 (95% CI 1.33, 2.14) for non-cardiovascular and non-cancer, and 1.51 (95% CI 1.30, 1.75) for all-cause mortality when compared with highly educated parous women. Moreover, we observed significant additive interactions between parity and education level on total cardiovascular disease mortality (P = 0.04), non-cardiovascular disease and non-cancer mortality (P = 0.01), and all-cause mortality (P = 0.005).

Conclusions

Nulliparity and low education levels are super-additively associated with total cardiovascular disease, non-cardiovascular and non-cancer, and all-cause mortality risks, suggesting that nulliparous women with low education levels need specific support for preventing mortality related to cardiovascular and other diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12905-022-01805-y.

The association of reproductive history with hypertension and obesity according to menopausal status: the J-MICC Study

Previous studies have reported that the number of pregnancies and childbirths affected the risk of cardiovascular diseases (CVDs). However, the influence of reproductive history on hypertension and obesity, which are important risk factors for CVDs, is still unclear. Moreover, this association may vary depending on menopausal status. We evaluated the association of reproductive history with hypertension and obesity using a large cross-sectional dataset from the Japan Multi-Institutional Collaborative Cohort Study (J-MICC Study). At the baseline survey, physical data, blood samples, and self-reported health questionnaires were collected. Participants with insufficient data were excluded, and 24,558 women from eight study regions were included in this study. Logistic regression analysis was conducted to evaluate the association of reproductive history with hypertension and obesity using multivariable-adjusted odds ratios. In premenopausal women, childbirth showed a generally protective effect on hypertension but not on obesity. In postmenopausal women, childbirth was positively associated with obesity and hypertension but not with hypertension after adjusting for BMI. In conclusion, reproductive history was associated with hypertension and obesity in a large Japanese population, and this association differed between premenopausal and postmenopausal women.

Immune cell type and DNA methylation vary with reproductive status in women: possible pathways for costs of reproduction

Background

Consistent with evolutionarily theorized costs of reproduction (CoR), reproductive history in women is associated with life expectancy and susceptibility to certain cancers, autoimmune disorders and metabolic disease. Immunological changes originating during reproduction may help explain some of these relationships.

Methodology

To explore the potential role of the immune system in female CoR, we characterized leukocyte composition and regulatory processes using DNA methylation (DNAm) in a cross-sectional cohort of young (20–22 years old) women differing in reproductive status.

Results

Compared to nulliparity, pregnancy was characterized by differential methylation at 828 sites, 96% of which were hypomethylated and enriched for genes associated with T-cell activation, innate immunity, pre-eclampsia and neoplasia. Breastfeeding was associated with differential methylation at 1107 sites (71% hypermethylated), enriched for genes involved in metabolism, immune self-recognition and neurogenesis. There were no significant differences in DNAm between nulliparous and parous women. However, compared to nullipara, pregnant women had lower proportions of B, CD4T, CD8T and natural killer (NK) cells, and higher proportions of granulocytes and monocytes. Monocyte counts were lower and NK counts higher among breastfeeding women, and remained so among parous women.

Implications

Our findings point to widespread differences in DNAm during pregnancy and lactation. These effects appear largely transient, but may accumulate with gravidity become detectable as women age. Nulliparous and parous women differed in leukocyte composition, consistent with more persistent effects of reproduction on cell type. These findings support transient (leukocyte DNAm) and persistent (cell composition) changes associated with reproduction in women, illuminating potential pathways contributing to CoR.

Lay Summary: Evolutionary theory and epidemiology support costs of reproduction (CoR) to women’s health that may involve changes in immune function. We report differences in immune cell composition and gene regulation during pregnancy and breastfeeding. While many of these differences appear transient, immune cell composition may remain, suggesting mechanisms for female CoR.

Frailty in ethnic minority women

In majority populations in high- and middle-income countries, women live longer yet experience higher levels of frailty than men of the same age. It is unclear whether this 'sex-frailty paradox' is present in ethnic minority populations. In this narrative review, we explore biological, behavioural and social factors associated with mortality, morbidity and frailty in women, particularly ethnic minority women. We ascertain that natural menopause occurs earlier in women of particular ethnicities. Ethnic minority women (living in high-income countries) have more children and higher rates of chronic disease and disability, all of which are associated with frailty. In some ethnic minorities, women are less likely to engage in deleterious health behaviours such as smoking and alcohol consumption. However, in others the reverse is true. Women from migrant ethnic minorities tend to have lower levels of physical activity. With time, they can also adopt adverse behavioural patterns of the majority population. Although the evidence is sparse, sex differences in health reporting and social assets, as well as gender roles, are likely to contribute to sex differences in frailty in ethnic minorities. Overall, ethnic minority women are a particularly vulnerable group, but the majority of risk factors for frailty appear to be mutable rather than fixed. Future research may examine interventions that target frailty in different races and ethnicities at individual, population and global levels.

Live birth/parity number and the risk of incident hypertension among parous women during over 13 years of follow-up

The effect of live birth/parity number on incident hypertension was investigated among Iranian parous women aged 30–70 years. The study population included 2188 normotensive women who were enrolled in 1999–2001. They were followed for incident hypertension (based on JNC 7 report) by 3‐year intervals up to April 2018. Multivariable Cox proportional hazard models, adjusted for a wide set of potential hypertension risk factors, reproductive factors, and pregnancy complications, were applied to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of the number of parity/live birth(s) for incident hypertension. Additionally, as a sensitivity analysis, age‐scale Cox regression was also done. During a median follow‐up of 13.5 years, 935 incident hypertension have occurred. Compared to those with two live births, the participants who had 3 and ≥4 live births were at higher risk of hypertension development by the HRs of 1.25 [95% CI: 1.02–1.55] and 1.39 [1.12–1.72], respectively, in the full‐adjusted model. Moreover, each additional live birth increased the risk of hypertension by a HR of 1.06 [95%CI: 1.02–1.11]. Results of parity number were also similar. Considering age as time scale also did not change the results generally. The authors found a significant interaction between live birth/parity number and age groups; the adverse effect of higher live birth/parity numbers on hypertension development was mainly found among those aged < 50 years. To sum up, compared to the live birth/parity number of two, Iranian women with ≥3 live birth/parity had a higher risk of incident hypertension; the issue was more prominent among younger mothers.

Sex Differences in Hypertrophic Cardiomyopathy: Interaction With Genetics and Environment

Purpose of Review

We explore the sex-specific interaction of genetics and the environment on the clinical course and outcomes of hypertrophic cardiomyopathy (HCM).

Recent Findings

Women account for approximately one-third of patients in specialist HCM centres and reported in observational studies. As a result, evidence informing clinical guideline recommendations is based predominantly on risk factors and outcomes seen in men. However, disease progression appears to be different between the sexes. Women present at a more advanced stage of disease, are older at diagnosis, have higher symptom burden, carry greater risk for heart failure and are at greater risk of mortality compared to men. Women are more likely to be gene-positive, while men are more likely to be gene-negative. The risk of sudden cardiac death and access to specialised care do not differ between the sexes.

Summary

Reporting sex-disaggregated results is essential to identify the mechanisms leading to sex differences in HCM.

Parity and later life risk for coronary heart disease among slum-dwelling women in Mysore, India

BACKGROUND

To examine the role of parity in coronary heart disease (CHD) among middle-aged Indian women living in government-designated slums in Mysore, India.

METHODS

Between October 2017 and May 2018, a cross-sectional study was carried out among women, 40-64 years of age, residing in government-designated slums in Mysore, India. In addition to socio-demographics, data were collected on CVD risk factors including use of tobacco and alcohol, diet, physical activity, sleep, quality of life, and personal and family history of chronic disease. Patients underwent a medical examination and a venous blood sample was taken for fasting lipid measurement. Resting electrocardiography was carried out by a trained medical technician. Multivariable logistic regression with associated 95% confidence intervals was used to examine the relationship between parity and coronary heart disease.

RESULTS

The prevalence of CHD in this sample of middle-aged women was 6.4%. Nulliparous women were at heightened risk for CHD compared to parous women with up to five live births. In the adjusted model, women who had 1-2 and 3-5 live births had 0.24 times lower odds (95% Confidence Interval [CI]: 0.05-1.29) and 0.38 times lower odds (95%CI: 0.178-0.87) of CHD, respectively, as compared to nulliparous women.

CONCLUSION

Among a fairly homogenous population of slum-dwelling women reporting almost universal breastfeeding for three or more months following birth, parity up to five births appeared protective against CHD. Further studies are needed to evaluate whether near universal breastfeeding rates in this population mediated the relationship of parity and CHD.

Higher Parity Is Associated With Lower Mortality in a European Population of Women With High Fertility: Results From Ireland

Research has often found a U- or J-shaped association between parity and mortality. Many researchers have suggested repeated pregnancy, childbirth, and lactation taxes the body beyond a certain parity level. Available research has concentrated on populations with controlled fertility or historic populations. Ireland presents an opportunity to explore these associations in a modern sample with high fertility. We use data from the Irish Longitudinal Study on Ageing (TILDA) to test whether parity is associated with mortality in women aged 50 years or over (n = 4177). We use Cox proportional hazards models to model survival and adjust for demographics and early life circumstances. We test whether a number of health characteristics mediate these effects. Models were also stratified by birth cohort to test possible cohort effects. Higher parity was associated with lower risk of mortality, even after adjustment for early life and socioeconomic circumstances. This effect was not mediated by current health characteristics. The effects were largely driven by those born between 1931 and 1950. Increasing parity is associated with decreasing mortality risk in this sample. The effects of parity could not be explained through any of the observed health characteristics. These findings are in contrast to much of the literature on this question in similar populations. Lack of fertility control in Ireland may have "selected" healthier women into high parity. Social explanations for these associations should be further explored.

Enhancement of Synaptic Characteristics Achieved by the Optimization of Proton-Electron Coupling Effect in a Solid-State Electrolyte-Gated Transistor

Presently, the 3-terminal artificial synapse device has been in focus for neuromorphic computing systems owing to its excellent weight controllability. Here, an artificial synapse device based on the 3-terminal solid-state electrolyte-gated transistor is proposed to achieve outstanding synaptic characteristics with a human-like mechanism at low power. Novel synaptic characteristics are accomplished by precisely tuning the threshold voltage using the proton-electron coupling effect, which is caused by proton migration inside the electrolyte. However, these synaptic characteristics are degraded because traps at the interface of channel/electrolyte disturb the proton-electron coupling effect. To minimize degradation, the oxygen plasma treatment is performed to reduce interface traps. As a result, symmetric weight updates and outstanding synaptic characteristics are achieved. Furthermore, high repeatability and long-term plasticity are observed at low operating power, which is essential for artificial synapses. Therefore, this study shows the progress of artificial synapses and proposes a promising method, a low-power neuromorphic system, to achieve high accuracy.

Number of parity/live birth(s) and cardiovascular disease among Iranian women and men: results of over 15 years of follow-up

Background

Most previous studies conducted in non-Middle Eastern populations have suggested that an increase in the number of parity/live birth(s) leads to cardiovascular disease (CVD) development, although their findings were inconclusive on this issue for both sexes. Biologic and socioeconomic pathways were suggested to explain this association. We studied this issue among urban Iranian men and women.

Methods

In this population-based cohort study, which included 3929 women and 2571 men aged ≥30 years, data for the number of parity/live birth(s) were obtained by a standard questionnaire. Participants were then annually followed for CVD events. Multivariable Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the number of parity/live birth(s) and other traditional CVD risk factors.

Results

During more than 15 years of follow-up, 456 and 524 CVD events have occurred among women and men, respectively. Among women, a J-shaped association was found between the number of live births and incident CVD with the lowest risk for women with two live births. Among women in multivariable analyses, each unit increase in parity had a HR of 1.05 (CI: 1.01–1.10), and having ≥4 parity was associated with a HR of 1.86 (0.97–3.56, p-value = 0.061). Among men, in comparison with participants who had 1 child, multivariable HRs of having 2, 3, and ≥ 4 children were 1.97 (1.24–3.12), 2.08 (1.31–3.31), and 2.08 (1.30–3.34), respectively.

Conclusion

To the best of our knowledge, the current study is the first report on this issue in the Middle East and North Africa region, a region with a high burden of CVD. It can now be suggested that the number of parity/live birth(s) is linked to CVD among the Iranian population, with this issue being more prominent among men. Further research is needed to support our results and clarify the pathways between the number of parity/live birth(s) and CVD development among Iranian populations by considering potential risk factors, especially psycho-socio-economic risk factors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-020-03499-2.

Parity predicts biological age acceleration in post-menopausal, but not pre-menopausal, women

Understanding factors contributing to variation in ‘biological age’ is essential to understanding variation in susceptibility to disease and functional decline. One factor that could accelerate biological aging in women is reproduction. Pregnancy is characterized by extensive, energetically-costly changes across numerous physiological systems. These ‘costs of reproduction’ may accumulate with each pregnancy, accelerating biological aging. Despite evidence for costs of reproduction using molecular and demographic measures, it is unknown whether parity is linked to commonly-used clinical measures of biological aging. We use data collected between 1999 and 2010 from the National Health and Nutrition Examination Survey (n = 4418) to test whether parity (number of live births) predicted four previously-validated composite measures of biological age and system integrity: Levine Method, homeostatic dysregulation, Klemera–Doubal method biological age, and allostatic load. Parity exhibited a U-shaped relationship with accelerated biological aging when controlling for chronological age, lifestyle, health-related, and demographic factors in post-menopausal, but not pre-menopausal, women, with biological age acceleration being lowest among post-menopausal women reporting between three and four live births. Our findings suggest a link between reproductive function and physiological dysregulation, and allude to possible compensatory mechanisms that buffer the effects of reproductive function on physiological dysregulation during a woman’s reproductive lifespan. Future work should continue to investigate links between parity, menopausal status, and biological age using targeted physiological measures and longitudinal studies.

Costs of reproduction and ageing in the human female

Evolutionary theories of ageing point to reproduction as a significant factor to consider when asking why ageing occurs and why there is inter-individual variation in its progression. Reproduction in human females is costly, in terms of energy, nutrients and metabolic adjustments. Thus, it is expected that women who experienced high reproductive effort resulting from multiple reproductive events will age faster. However, the evidence for long-term negative effects of reproduction is not conclusive. The lack of understanding of whether there are trade-offs between reproduction and ageing in women is partly due to methodological challenges. The costs of reproduction are often calculated based only on parity, while other elements contributing to these costs (e.g. breastfeeding, timing of reproduction) are neglected, which may significantly underestimate the total costs and obscure the all-important inter-individual variation in such costs. Costs must be evaluated in relation to individual characteristics, including developmental conditions, nutritional status and social support that a mother receives during reproduction. Furthermore, ageing and health must be assessed based on comprehensive markers rather than arbitrarily assembled variables. Finally, longitudinal rather than cross-sectional studies and new statistical approaches are needed to reveal how much of a decline in health and progressing ageing can actually be attributed to past reproductive processes. This article is part of the theme issue 'Evolution of the primate ageing process'.

Association between the reproductive health of young women and cardiovascular disease in later life: umbrella review

OBJECTIVE

To consolidate evidence from systematic reviews and meta-analyses investigating the association between reproductive factors in women of reproductive age and their subsequent risk of cardiovascular disease.

DESIGN

Umbrella review.

DATA SOURCES

Medline, Embase, and Cochrane databases for systematic reviews and meta-analyses from inception until 31 August 2019.

REVIEW METHODS

Two independent reviewers undertook screening, data extraction, and quality appraisal. The population was women of reproductive age. Exposures were fertility related factors and adverse pregnancy outcomes. Outcome was cardiovascular diseases in women, including ischaemic heart disease, heart failure, peripheral arterial disease, and stroke.

RESULTS

32 reviews were included, evaluating multiple risk factors over an average follow-up period of 7-10 years. All except three reviews were of moderate quality. A narrative evidence synthesis with forest plots and tabular presentations was performed. Associations for composite cardiovascular disease were: twofold for pre-eclampsia, stillbirth, and preterm birth; 1.5-1.9-fold for gestational hypertension, placental abruption, gestational diabetes, and premature ovarian insufficiency; and less than 1.5-fold for early menarche, polycystic ovary syndrome, ever parity, and early menopause. A longer length of breastfeeding was associated with a reduced risk of cardiovascular disease. The associations for ischaemic heart disease were twofold or greater for pre-eclampsia, recurrent pre-eclampsia, gestational diabetes, and preterm birth; 1.5-1.9-fold for current use of combined oral contraceptives (oestrogen and progesterone), recurrent miscarriage, premature ovarian insufficiency, and early menopause; and less than 1.5-fold for miscarriage, polycystic ovary syndrome, and menopausal symptoms. For stroke outcomes, the associations were twofold or more for current use of any oral contraceptive (combined oral contraceptives or progesterone only pill), pre-eclampsia, and recurrent pre-eclampsia; 1.5-1.9-fold for current use of combined oral contraceptives, gestational diabetes, and preterm birth; and less than 1.5-fold for polycystic ovary syndrome. The association for heart failure was fourfold for pre-eclampsia. No association was found between cardiovascular disease outcomes and current use of progesterone only contraceptives, use of non-oral hormonal contraceptive agents, or fertility treatment.

CONCLUSIONS

From menarche to menopause, reproductive factors were associated with cardiovascular disease in women. In this review, presenting absolute numbers on the scale of the problem was not feasible; however, if these associations are causal, they could account for a large proportion of unexplained risk of cardiovascular disease in women, and the risk might be modifiable. Identifying reproductive risk factors at an early stage in the life of women might facilitate the initiation of strategies to modify potential risks. Policy makers should consider incorporating reproductive risk factors as part of the assessment of cardiovascular risk in clinical guidelines.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019120076.

Association between gravidity and risk of metabolic syndrome: Results of Tabari cohort study

BACKGROUND AND AIMS

The purpose of the present study was to investigate the association of gravidity and age at first pregnancy with metabolic syndrome in a large-scale, population-based cohort study in Iran.

METHODS

The present secondary analysis was conducted on a subset of the population (5739 women with at least one pregnancy) enrolled in the Tabari cohort study. Reproductive history was collected using a structured questionnaire. The relationship of gravidity and age at first pregnancy with metabolic syndrome and its components was analyzed using the logistic regression model.

RESULTS

The results showed that after adjustment for confounding variables, the odds of having metabolic syndrome was not significantly associated with age at first pregnancy (P = 0.269) and gravidity (P = 0.504). However, there was an association between hypertension and age at first pregnancy (OR = 0.32, 95% CI = 0.12-0.82; P = 0.03). Additionally, waist circumference was also associated with gravidity (OR = 2.17, 95% CI = 1.37-3.35).

CONCLUSION

As the findings indicated, age at first pregnancy and gravidity were not associated with the odds of having metabolic syndrome. However, a relationship was found between first pregnancy at the age of >35 years and the decreased risk of hypertension. Gravidity was also found to be a dose-dependent risk factor for increased waist circumference.

Gravidity, parity, blood pressure and mortality among women in Bangladesh from the HEALS cohort

OBJECTIVES

Despite a hypothesised connection of reproductive history with hypertension and mortality, the nature of this association is poorly characterised. We evaluated the association of parity and gravidity with blood pressure, hypertension and all-cause mortality.

DESIGN

Prospective cohort study.

SETTING

Health Effects of Arsenic Longitudinal Study cohort in rural Bangladesh.

PARTICIPANTS

There were 21 634 Bangladeshi women recruited in 2000-2002, 2006-2008 and 2010-2014 included in the present analysis.

METHODS

Reproductive history was ascertained through an interviewer-administered questionnaire at the baseline visit. Blood pressure was measured by a trained study physician following a standard protocol at the baseline visit. Vital status was ascertained at the biennial follow-up of study participants through June 2017. Linear and logistic regression models estimated the relationship between parity and gravidity with blood pressure and hypertension, respectively. Cox proportional hazards models estimated the relationship with all-cause mortality only among women aged >45 years.

RESULTS

Diastolic blood pressure was lowest in women with parity one (reference) and elevated in nulliparous women (adjusted % change=3.12; 95% CI 1.93 to 4.33) and women with parity >2 (adjusted % change=1.71; 95% CI 1.12 to 2.31). The associations with nulliparity were stronger for women aged >45 years. Similar association patterns were observed with hypertension. Further, in nulliparous women aged >45 years, 265 deaths (6.6%) were ascertained during the follow-up period (median follow-up time=8 years), and we observed suggestive elevated risks of all-cause mortality (adjusted HR 3.83; 95% CI 0.74 to 19.78). The relationships between reproductive history, blood pressure, hypertension and mortality were similar when modelling reproductive history as gravidity rather than parity.

CONCLUSIONS

For women in rural Bangladesh, nulliparity and nulligravidity appear to be associated with higher blood pressure and subsequent elevated risk of mortality.

Heart Failure in Women With Hypertensive Disorders of Pregnancy: Insights From the Cardiovascular Disease in Norway Project

Hypertensive disorders of pregnancy (HDP) have been associated with heart failure (HF). It is unknown whether concurrent pregnancy complications (small-for-gestational-age or preterm delivery) or recurrent HDP modify HDP-associated HF risk. In this cohort study, we included Norwegian women with a first birth between 1980 and 2004. Follow-up occurred through 2009. Cox models examined gestational hypertension and preeclampsia in the first pregnancy as predictors of a composite of HF-related hospitalization or HF-related death, with assessment of effect modification by concurrent small-for-gestational-age or preterm delivery. Additional models were stratified by final parity (1 versus ≥2 births) and tested associations with recurrent HDP. Among 508 422 women, 565 experienced incident HF over a median 11.8 years of follow-up. After multivariable adjustment, gestational hypertension in the first birth was not significantly associated with HF (hazard ratio, 1.41 [95% CI, 0.84-2.35], P=0.19), whereas preeclampsia was associated with a hazard ratio of 2.00 (95% CI, 1.50-2.68, P<0.001). Among women with HDP, risks were not modified by concurrent small-for-gestational-age or preterm delivery (P_interaction=0.42). Largest hazards of HF were observed in women whose only lifetime birth was complicated by preeclampsia and women with recurrent preeclampsia. HF risks were similar after excluding women with coronary artery disease. In summary, women with preeclampsia, especially those with one lifetime birth and those with recurrent preeclampsia, experienced increased HF risk compared to women without HDP. Further research is needed to clarify causal mechanisms.

Frailty: A cost incurred by reproduction?

Evolutionary theories of senescence, such as the ‘disposable soma’ theory, propose that natural selection trades late survival for early fecundity. ‘Frailty’, a multidimensional measure of health status, may help to better define the long-term consequences of reproduction. We examined the relationship between parity and later life frailty (as measured by the Frailty Index) in a sample of 3,534 adults aged 65 years and older who participated in the English Longitudinal Study of Ageing. We found that the most parous adults were the most frail and that the parity-frailty relationship was similar for both sexes. Whilst this study provided some evidence for a ‘parity-frailty trade-off’, there was little support for our hypothesis that the physiological costs of childbearing influence later life frailty. Rather, behavioural and social factors associated with rearing many children may have contributed to the development of frailty in both sexes.

Pregnancy, postpartum and parity: Resilience and vulnerability in brain health and disease

Risk and resilience in brain health and disease can be influenced by a variety of factors. While there is a growing appreciation to consider sex as one of these factors, far less attention has been paid to sex-specific variables that may differentially impact females such as pregnancy and reproductive history. In this review, we focus on nervous system disorders which show a female bias and for which there is data from basic research and clinical studies pointing to modification in disease risk and progression during pregnancy, postpartum and/or as a result of parity: multiple sclerosis (MS), depression, stroke, and Alzheimer's disease (AD). In doing so, we join others (Shors, 2016; Galea et al., 2018a) in aiming to illustrate the importance of looking beyond sex in neuroscience research.

Relationships Between Reproductive History and Mortality From Cardiovascular Diseases Among Japanese Women: The Japan Collaborative Cohort Study for Evaluation of Cancer Risk (JACC) Study

Background

Reproductive history has been addressed as a risk factor for cardiovascular disease (CVD). We examined the relationship between reproductive history and CVD mortality in Japanese women.

Methods

We followed 53,836 women without previous CVD or cancer history from 1988–1990 to 2009 in a prospective cohort study. Hazard ratios (HRs) and 95% confidence intervals (CIs) of CVD mortality were estimated according to the number of deliveries and maternal age at first delivery.

Results

During the follow-up, 2,982 CVD-related deaths were identified. There was U-shaped association between the number of deliveries and risk of CVD mortality with reference to three deliveries, although the excess risk of CVD mortality associated with ≥5 deliveries was of borderline statistical significance. The corresponding multivariable HRs were 1.33 (95% CI, 1.12–1.58) and 1.11 (95% CI, 0.99–1.24). In addition, higher CVD mortality was associated with maternal age ≥28 years at first delivery than maternal age of 24–27 years at first delivery. The multivariable HRs were 1.22 (95% CI, 1.10–1.36) for 28–31 years at first delivery and 1.26 (95% CI, 1.04–1.52) for ≥32 years at first delivery. Moreover, among women with ≥3 deliveries, maternal age ≥28 years at first delivery was associated with 1.2- to 1.5-fold increased CVD mortality.

Conclusion

The number of deliveries showed a U-shaped association with risk of CVD mortality. Higher maternal age at first delivery was associated with an increased risk of CVD mortality, and excessive risk in women aged ≥28 years at first delivery was noted in those with ≥3 deliveries.

Sex-specific risk factors for cardiovascular disease in women-making cardiovascular disease real

PURPOSE OF REVIEW

Sex-specific differences in pathophysiology, prevalence, and impact of cardiovascular disease (CVD) risk factors may explain the high cardiovascular mortality rates in women.

RECENT FINDINGS

We review the sex differences in traditional risk factors (dyslipidemia, hypertension, diabetes, and smoking) and nontraditional risk factors (menopause and hormones, pregnancy, inflammation and autoimmune diseases, anemia, depression, and migraines) and their prognostic and therapeutic implications.

SUMMARY

Recent research indicates that with respect to traditional risk factors such as dyslipidemia, hypertension, diabetes, and smoking, women appear to have a similar risk of CVD when compared to men. The risk is accelerated after menopause, possibly because of vascular and lipid profile changes. Pregnancy offers a unique opportunity and window to screen otherwise healthy women who may be at an increased risk of CVD in the future. Clinicians should be aware of other novel risk factors including inflammation, anemia, migraines, and depression, and further studies are warranted in order to identify therapeutic implications for these conditions and CVD risk.

Association between reproductive factors and carotid atherosclerosis in post-menopausal women

OBJECTIVES

Assessment of cardiovascular risk in women is specific and hormonal factors should be considered to avoid its underestimation. So far, studies on this issue are lacking and the impact of reproductive factors on cardiovascular risk has yet to be determined. We study the association between reproductive factors and carotid atherosclerosis, a non-invasive marker of cardiovascular diseases, in post-menopause.

STUDY DESIGN

In this cross-sectional study, data were analyzed from post-menopausal women with at least one cardiovascular risk factor followed through a dedicated healthcare pathway at the Lille University Hospital between January 1st, 2013 and December 31st, 2016.

MAIN OUTCOME AND MEASURES

The primary outcome was the presence of plaque or stenosis at carotid ultrasound.

RESULTS

We included 370 post-menopausal women with a mean age of 63.4 ± 0.5 years. Carotid atherosclerosis was found in 161 (43,3%) women. Women with 3 or more children had higher odds of having carotid atherosclerosis than women with fewer than 3 children after adjustment for age, OR 1,69 [CI 95% 1,09-2,61], p = 0,019, and after further adjustment for anthropometric measures, traditional cardiovascular risk factors and pregnancy-related complications: OR 1,65 [CI 95% 1,05-2,62], p = 0,031. No other reproductive factor was significantly associated with carotid atherosclerosis.

CONCLUSIONS

A higher parity was associated with higher odds of carotid atherosclerosis independently of age, traditional risk factors, anthropometric measures and gestational diseases among post-menopausal women at risk of cardiovascular diseases. This suggests the importance of considering the number of children when assessing cardiovascular risk in women.

Does pregnancy complication history improve cardiovascular disease risk prediction? Findings from the HUNT study in Norway

AIM

To evaluate whether history of pregnancy complications [pre-eclampsia, gestational hypertension, preterm delivery, or small for gestational age (SGA)] improves risk prediction for cardiovascular disease (CVD).

METHODS AND RESULTS

This population-based, prospective cohort study linked data from the HUNT Study, Medical Birth Registry of Norway, validated hospital records, and Norwegian Cause of Death Registry. Using an established CVD risk prediction model (NORRISK 2), we predicted 10-year risk of CVD (non-fatal myocardial infarction, fatal coronary heart disease, and non-fatal or fatal stroke) based on established risk factors (age, systolic blood pressure, total and HDL-cholesterol, smoking, anti-hypertensives, and family history of myocardial infarction). We evaluated whether adding pregnancy complication history improved model fit, calibration, discrimination, and reclassification. Among 18 231 women who were parous, ≥40 years of age, and CVD-free at start of follow-up, 39% had any pregnancy complication history and 5% experienced a CVD event during a median follow-up of 8.2 years. While pre-eclampsia and SGA were associated with CVD in unadjusted models (HR 1.96, 95% CI 1.44-2.65 for pre-eclampsia and HR 1.46, 95% CI 1.18-1.81 for SGA), only pre-eclampsia remained associated with CVD after adjusting for established risk factors (HR 1.60, 95% CI 1.16-2.17). Adding pregnancy complication history to the established prediction model led to small improvements in discrimination (C-index difference 0.004, 95% CI 0.002-0.006) and reclassification (net reclassification improvement 0.02, 95% CI 0.002-0.05).

CONCLUSION

Pre-eclampsia independently predicted CVD after controlling for established risk factors; however, adding pre-eclampsia, gestational hypertension, preterm delivery, and SGA made only small improvements to CVD prediction among this representative sample of parous Norwegian women.

The long and short term effects of motherhood on the brain

Becoming a mother is associated with dramatic changes in physiology, endocrinology, immune function, and behaviour that begins during pregnancy and persists into the postpartum. Evidence also suggests that motherhood is accompanied by long-term changes in brain function. In this review, we summarize the short (pregnancy and postpartum) and long-term (beyond the postpartum and into middle age) effects of pregnancy and motherhood on cognition, neuroplasticity, and neuroimmune signalling. We also discuss the effects of previous history of pregnancy and motherhood (parity) on brain health and disease (neurodegenerative diseases and stroke outcomes) and on efficacy of hormone and antidepressant treatments. Finally, we argue that pregnancy and motherhood are unique female experiences that need to be taken into account to better understand female brain function and aging.

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

AIMS

Duration of endogenous estrogen exposure is apparently associated with risk of cardiovascular disease, the longer durations being more cardiovascular disease protective in women. We aimed to investigate the association of cumulative duration of endogenous estrogen exposure over women's reproductive lifespans with cardiovascular disease outcomes.

MAIN METHODS

For the purpose of the present study, of 10,192 female participants, after excluding those using HRT (n = 84), 3656 women, aged ≥30 years, who met eligibility criteria were selected and divided into three groups based on tertiles (T1, T2, T3) of exposure durations to endogenous estrogen. Cox proportional hazards regression model was used to estimate associations between exposure durations and cardiovascular disease outcomes.

KEY FINDINGS

Cardiovascular events occurred in 352 participants over a median follow-up of 14.2 (13.5, 14.6) years (7.7 per 1000 person years; 95% CI: 6.9-8.5). Incidence of outcome was 10.9 per 1000 person years (CI, 9.4-12.8) in T₁, 7.2 per 1000 person years (CI, 6.0-8.7) in T₂, and 5.1 per 1000 person years (CI, 4.1-6.4) in T₃. The hazard ratio of cardiovascular events in T₁ was significantly higher than that inT₃, before and after adjustment for confounding variables. Before adjustment, women in T₂ had a 40% higher risk of CVD, compared to T₃; after adjustment however the risk was similar to that of women in T₃.

SIGNIFICANCE

Shorter durations of exposure to endogenous estrogen may increase the risk of cardiovascular diseases among these women later in life. Future studies should target women with short duration of exposure for timely screening and implementation of preventative interventions.

Effects of multiparity on left ventricular diastolic dysfunction in women: cross-sectional study of the KoRean wOmen'S chest pain rEgistry (KoROSE)

OBJECTIVES

To investigate the association between left ventricular (LV) diastolic dysfunction and multiparity in patients with suspected coronary artery disease (CAD).

DESIGN

Cross-sectional study.

SETTING

Linked secondary and tertiary care records from 29 cardiac centres which participated in KoRean wOmen'S chest pain rEgistry.

PARTICIPANTS

960 women with suspected CAD who underwent invasive coronary angiography from February 2011 to May 2017. The patients were classified by parity number, as follows: low-parity, 0 to <3; multiparity, ≥3 pregnancies.

MAIN OUTCOME MEASURE

Prevalence of LV diastolic dysfunction.

RESULTS

There were 302 and 658 low-parity and multiparity patients, respectively. The prevalence of LV diastolic dysfunction was significantly higher in the multiparity than in the low-parity group. The multiparity group had significantly lower E and e´ septal velocities and E/A ratio, and had a significantly higher E/e´ ratio and right ventricular systolic pressure, which are parameters of LV diastolic dysfunction, than the low-parity group. The prevalence of CAD was significantly higher in the multiparity than in the low-parity group. Receiver operating characteristic curve analysis identified a parity of 2.5 as the cut-off for predicting LV diastolic dysfunction (area under the curve, 0.66; sensitivity, 74.1%; specificity, 52.0%; 95% CI 0.607 to 0.706; p<0.001). After adjustment for confounding factors, multivariate regression analysis showed that multiparity had a 1.80-fold increased risk for LV diastolic dysfunction (OR 1.80, 95% CI 1.053 to 3.081, p=0.032).

CONCLUSIONS

The prevalence of LV diastolic dysfunction was higher in multiparity than in low-parity women with suspected CAD. Multiparity was an independent risk factor for LV diastolic dysfunction. LV diastolic dysfunction should be evaluated in multiparous women for the risk of subsequent cardiovascular disease and facilitate the initiation of appropriate treatment.

Contributions of sex to cerebrovascular function and pathology

Sex differences exist in how cerebral blood vessels function under both physiological and pathological conditions, contributing to observed sex differences in risk and outcomes of cerebrovascular diseases (CBVDs), such as vascular contributions to cognitive impairment and dementia (VCID) and stroke. Throughout most of the lifespan, women are protected from CBVDs; however, risk increases following menopause, suggesting sex hormones may play a significant role in this protection. The cerebrovasculature is a target for sex hormones, including estrogens, progestins, and androgens, where they can influence numerous vascular functions and pathologies. While there is a plethora of information on estrogen, the effects of progestins and androgens on the cerebrovasculature are less well-defined. Estrogen decreases cerebral tone and increases cerebral blood flow, while androgens increase tone. Both estrogens and androgens enhance angiogenesis/cerebrovascular remodeling. While both estrogens and androgens attenuate cerebrovascular inflammation, pro-inflammatory effects of androgens under physiological conditions have also been demonstrated. Sex hormones exert additional neuroprotective effects by attenuating oxidative stress and maintaining integrity and function of the blood brain barrier. Most animal studies utilize young, healthy, gonadectomized animals, which do not mimic the clinical conditions of aging individuals likely to get CBVDs. This is also concerning, as sex hormones appear to mediate cerebrovascular function differently based on age and disease state (e.g. metabolic syndrome). Through this review, we hope to inspire others to consider sex as a key biological variable in cerebrovascular research, as greater understanding of sex differences in cerebrovascular function will assist in developing personalized approaches to prevent and treat CBVDs.

Parity and risk of maternal cardiovascular disease: A dose-response meta-analysis of cohort studies

BACKGROUND

Parity has been reported to play an important role in the development of cardiovascular disease; however, the results are still controversial. We aimed to conduct a meta-analysis of cohort studies to assess quantitatively the association between parity and cardiovascular disease risk.

METHODS

PubMed and Web of Science databases were searched to 1 June 2018, supplemented by manual searches of the bibliographies of retrieved articles. And multivariate-adjusted relative risks were pooled by using random-effects models. Restricted cubic spline analysis with four knots was used to explore the relationship of parity and the risk of cardiovascular disease.

RESULTS

Ten cohort studies involving 150,512 incident cases of cardiovascular disease among 3,089,929 participants were included in the meta-analysis. A significant association between parity and cardiovascular disease risk was observed while comparing parity with nulliparity, with a summarised relative risk of 1.14 (95% confidence interval (CI) 1.09-1.18; I² = 62.0%, P = 0.002). In the dose-response analysis, we observed a potential non-linear J-shaped dose-response relationship between the number of parity and cardiovascular disease risk, the summary risk estimates for an increase of one live birth was 1.04 (95% CI 1.02-1.05), with significant heterogeneity ( I² = 89.6%). In addition, the similar J-shaped associations between parturition number and cardiovascular disease, ischaemic heart disease or stroke risk were also observed.

CONCLUSIONS

Our findings suggest that ever parity is related to cardiovascular disease risk and there is an association between the number of pregnancies and the risk of cardiovascular disease. Since the number of included studies was limited, further studies are warranted to confirm our findings.

Mechanisms of Sex Disparities in Cardiovascular Function and Remodeling

Epidemiological studies demonstrate disparities between men and women in cardiovascular disease prevalence, clinical symptoms, treatments, and outcomes. Enrollment of women in clinical trials is lower than men, and experimental studies investigating molecular mechanisms and efficacy of certain therapeutics in cardiovascular disease have been primarily conducted in male animals. These practices bias data interpretation and limit the implication of research findings in female clinical populations. This review will focus on the biological origins of sex differences in cardiovascular physiology, health, and disease, with an emphasis on the sex hormones, estrogen and testosterone. First, we will briefly discuss epidemiological evidence of sex disparities in cardiovascular disease prevalence and clinical manifestation. Second, we will describe studies suggesting sexual dimorphism in normal cardiovascular function from fetal life to older age. Third, we will summarize and critically discuss the current literature regarding the molecular mechanisms underlying the effects of estrogens and androgens on cardiac and vascular physiology and the contribution of these hormones to sex differences in cardiovascular disease. Fourth, we will present cardiovascular disease risk factors that are positively associated with the female sex, and thus, contributing to increased cardiovascular risk in women. We conclude that inclusion of both men and women in the investigation of the role of estrogens and androgens in cardiovascular physiology will advance our understanding of the mechanisms underlying sex differences in cardiovascular disease. In addition, investigating the role of sex-specific factors in the development of cardiovascular disease will reduce sex and gender disparities in the treatment and diagnosis of cardiovascular disease. © 2019 American Physiological Society. Compr Physiol 9:375-411, 2019.

MRI-derived aortic characteristics after pregnancy: The AMBITYON study

OBJECTIVES

Pregnancy and pregnancy complications have been associated with increased arterial stiffness even at young age. In this study we assessed the impact of parity on CMR-derived aortic characteristics as early markers of atherosclerosis and arterial stiffness in healthy women between 25 and 35 years.

STUDY DESIGN

We studied 68 women who participated in the AMBITYON study, a prospective population-based cohort study for assessment of atherosclerotic burden by MRI and traditional CVD risk factors in healthy, young adults. Of these women, 40 (58.8%) were nulliparous, 13 (19.1%) were primiparous and 15 (22.1%) were multiparous.

MAIN OUTCOME MEASURES

Descending thoracic aortic wall thickness (AWT) and pulse wave velocity (PWV) were measured using 3.0T CMR.

RESULTS

AWT measurements were similar between nulliparous women and primi- or multiparous women (1.6 mm ± 0.2 mm vs. 1.6 mm ± 0.2 mm; p = 0.79). Correction for age and systolic blood pressure did not change these results. Applying percentile based cut-off values showed a non-significant increase in AWT in parous women. PWV measurements did not differ between nulliparous women and parous women (4.5 m/s ± 0.7 m/s vs. 4.5 m/s ± 0.8 m/s; p = 0.78). Correction for age and systolic blood pressure did not influence these results. Using percentile based cut-off values, showed an increasing likelihood of higher PWV-values in parous women, although not statistically significant.

CONCLUSIONS

Direct measurement of aortic AWT and PWV by CMR showed no difference between nulliparous and parous women, probably indicating limited effect of pregnancy on arterial stiffness and early markers of atherosclerosis.

TRIAL REGISTRATION

Netherlands Trial Register (NTR) number: 4742.

Women's prepregnancy lipid levels and number of children: a Norwegian prospective population-based cohort study

OBJECTIVE

To study prepregnancy serum lipid levels and the association with the number of children.

DESIGN

Prospective, population-based cohort.

SETTING

Linked data from the Cohort of Norway and the Medical Birth Registry of Norway.

PARTICIPANTS

2645 women giving birth to their first child during 1994-2003 (488 one-child mothers and 2157 women with ≥2 births) and 1677 nulliparous women.

MAIN OUTCOME MEASURES

ORs for no and one lifetime pregnancy (relative to ≥2 pregnancies) obtained by multinomial logistic regression, adjusted for age at examination, education, body mass index (BMI), smoking, time since last meal and oral contraceptive use.

RESULTS

Assessed in quintiles, higher prepregnant triglyceride (TG) and TG to high-density lipoprotein (TG:HDL-c) ratio levels were associated with increased risk of one lifetime pregnancy compared with having ≥2 children. Compared with the highest quintile, women in the lowest quintile of HDL cholesterol levels had an increased risk of one lifetime pregnancy (OR 1.7, 95% CI 1.2 to 2.4), as were women with the highest low-density lipoprotein (LDL) cholesterol, TG and TG:HDL-c ratio quintiles (compared with the lowest) (OR 1.2, 95% CI 0.8 to 1.7; OR 2.2, 95% CI 1.5 to 3.2; and OR 2.2, 95% CI 1.5 to 3.2, respectively). Similar effects were found in women with BMI≥25 and the highest LDL and total cholesterol levels in risk of lifetime nulliparity.

CONCLUSION

Women with unfavourable prepregnant lipid profile had higher risk of having no or only one child. These findings substantiate an association between prepregnant serum lipid levels and number of children. Previously observed associations between low parity and increased cardiovascular mortality may in part be due to pre-existing cardiovascular disease lipid risk factors.

Cardiovascular disease after transplantation: an emerging role of the immune system

Cardiovascular disease (CVD) after transplantation remains a major concern. Little is known about what drives the increased cardiovascular risk in transplant recipients apart from traditional risk factors. The immune system is involved in the pathogenesis of hypertension, atherosclerosis, and coronary artery disease in the general population. Recently, inhibition of interleukin 1 - β by canakinumab versus placebo decreased the incidence of cardiovascular events. Emerging evidence points to a role of adaptive cellular immunity in the development of CVD. Especially, expansion of pro-inflammatory and antiapoptotic cytotoxic CD4⁺ CD28^null T cells is closely associated with incident CVD in various study populations including transplant recipients. The association of cytomegalovirus exposure with increased cardiovascular mortality might be explained by its capacity to upregulate these cytotoxic cells. Also, humoral immunity seems to be relevant for cardiovascular outcome in transplant recipients. Panel-reactive antibodies at baseline and donor-specific antibodies are independently associated with poor cardiovascular outcome after kidney transplantation. Cardiovascular effects of immunosuppressive drugs and statins do not only imply indirect positive or negative effects on traditional cardiovascular risk factors but also intrinsic immunological effects. How immunosuppressive drugs modify atherosclerosis largely remains elusive.

"Ikigai", Subjective Wellbeing, as a Modifier of the Parity-Cardiovascular Mortality Association - The Japan Collaborative Cohort Study

BACKGROUND

Nulliparity is associated with an excess risk of cardiovascular disease (CVD). "Ikigai", subjective wellbeing in Japan, is associated with reduced risk of CVD. The impact of ikigai on the association between parity and the risk of CVD, however, has not been reported.Methods and Results:A total of 39,870 Japanese women aged 40-79 years without a history of CVD, cancer or insufficient information at baseline in 1988-1990, were enrolled and followed until the end of 2009. They were categorized into 7 groups according to parity number 0-≥6. Using Cox regression hazard modeling, the associations between parity and mortality from stroke, coronary artery disease, and total CVD were investigated. During the follow-up period, 2,121 total CVD deaths were documented. No association was observed between parity and stroke and CVD mortality in women with ikigai, but there was an association in those without ikigai. The multivariable hazard ratios of stroke and total CVD mortality for nulliparous women without ikigai vs. those with 1 child were 1.87 (95% CI: 1.15-3.05) and 1.46 (95% CI: 1.07-2.01), respectively, and that for stroke mortality in high parity women without ikigai was 1.56 (95% CI: 1.00-2.45).

CONCLUSIONS

Nulliparous or high parity women without ikigai had higher mortality from stroke and/or total CVD, suggesting that ikigai attenuated the association between parity and CVD mortality in Japanese women.

Gravidity is not associated with telomere length in a biracial cohort of middle-aged women: The Coronary Artery Risk Development in Young Adults (CARDIA) study

OBJECTIVE

Having experienced 2-3 births is associated with reduced mortality versus women with <2 or ≥4 births. The effect of 2-3 births on lifespan may be associated with delayed cellular aging. We hypothesized telomere length, a marker of cellular aging, would be longer in women who had 2-3 pregnancies.

METHODS

Leukocyte telomere length was measured using quantitative real-time polymerase chain reaction in 620 women in CARDIA at the year 15 and 20 exams, expressed as the ratio of telomere repeat copy number to single-copy gene copy number (T/S). Number of pregnancies at the time of telomere length measurement was obtained (mean age = 41±0.1 years, average gravidity = 2.64±0.1 pregnancies). Participants were divided into 4 groups by number of pregnancies: 0, 1, 2-3, and ≥4, to test for differences in telomere length by gravidity group.

RESULTS

The mean and SD for telomere length was 0.98 ± 0.20 T/S in the whole cohort. There were no differences in mean telomere length between groups; 0.98±0.02 T/S in women with 0 pregnancies, 1.01±0.02 T/S in women with 1 pregnancy, 0.97±0.01 T/S in women with 2-3 pregnancies, and 0.99±0.02 T/S in women with ≥4 pregnancies (p = 0.51). We defined high-risk (shorter) telomere length as ≤25th percentile, and low-risk (longer) telomere length as ≥75 percentile. There were no differences in the prevalence of high-risk or low-risk telomere length between gravidity groups.

CONCLUSIONS

Gravidity was not associated with telomere length in early middle age; the protective association of 2-3 births may act through other mechanisms.