Parity and Risk of Coronary Heart Disease in Middle-aged and Older Chinese Women

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, cardiovascular health, and microchimerism

PURPOSE OF REVIEW

To provide an updated review of scientific literature concerning associations between pregnancy and cardiovascular health among women, and to discuss a possible impact of microchimerism on the association.

RECENT FINDINGS

In most studies, pregnancy and childbirth is associated with increased risk of cardiovascular disease in women. Some ascribe the association mainly to lifestyle, whereas others suggest that pregnancy itself negatively affects women's cardiovascular health. Pregnancy is a natural source of microchimerism, which in turn markedly affects female health. The only study published in the area surprisingly shows that among middle-aged women, male-origin microchimerism (MOM) is associated with half the risk of developing ischemic heart disease (IHD). No similar association is found between MOM and ischemic stroke.

SUMMARY

The sparse evidence published suggests reduced risk of developing IHD among MOM-positive women. Despite the association being biologically plausible, replication of the findings is warranted to support that this is not a chance finding.

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.

Socio-demographic characteristics and outcomes of pregnant women who delivered prior to and after the termination of the one-child policy in China: a comparative study

Background

The new Chinese fertility policy has recently received widespread public attention. However, there are few studies available on the comprehensive epidemiology of maternal and infant health with respect to the characteristic changes of childbearing women. In the study, we compared the maternal characteristics and pregnancy outcomes at different time points according to policy adjustments, accessed the possible relationship among these factors, and evaluated the impacts of these policies for medical and policy assistance.

Methods

This was a retrospective study. Data were collected from three representative hospitals in Zhejiang Province using stratified random sampling. The annual number of births, and maternal and child healthcare levels were the determining factors of sampling. Women who gave birth in November of 2012, 2014, and 2016 were recruited in accordance with the time of the change in the fertility policy, and we explored the differences in maternal socio-demographic characteristics, delivery mode and pregnancy outcomes.

Results

A total of 11,718 women were recruited, including 3480, 4044, and 4194 in November of 2012, 2014, and 2016, respectively. The proportions of multiparous women, women who aged ≥35 years, who received higher education, who had previous cesarean sections (CS), and who delivered in a high level hospital increased over time. In 2016, multipara accounted for 49.12, 14.47% were aged ≥35 years, nearly half of women had previous CS and delivered in a provincial hospital, 41.73% gave birth by CS, and 31.62% suffered pregnancy complications. The results of multiple logistic regression mode showed CS risk decreased significantly in 2014 (OR_adj = 0.62; 95% CI, 0.55–0.67) relative to 2012, and risks of pregnancy complications (OR_adj = 2.30; 95% CI, 1.86–2.83) and multiple births (OR_adj = 3.25; 95% CI, 2.19–4.83) only increased in 2016 compared to 2012.

Conclusions

Some pregnancy outcomes increased as several key characteristics of childbearing women changed after China ended its “one-child” policy. This suggests that policy providers and medical staff need to strengthen healthcare in a consistent fashion regarding changes in birth policy.

Neural control of blood pressure during pregnancy in humans

PURPOSE

Previous microneurographic studies found that muscle sympathetic nerve activity (MSNA) increased in normotensive pregnant women and was even greater in women with gestational hypertension and preeclampsia during the third trimester. It is possible that sympathetic activation during the latter months of normal pregnancy helps return arterial pressure to non-pregnant levels. However, when the increase in sympathetic activity is excessive, hypertension ensues. The key question that must be addressed is whether sympathetic activation develops early during pregnancy and remains high throughout gestation, or whether this sympathetic overactivity only occurs at term, providing the substrate for preeclampsia and other pregnancy-associated cardiovascular complications.

METHODS

This was a literature review of autonomic neural control during pregnancy.

RESULTS

Recent work from our laboratory and other laboratories showed that in healthy women resting MSNA increased in early pregnancy, increased further in late pregnancy, and returned to the pre-pregnancy levels shortly after delivery. We found that women who exhibited excessive sympathetic activation during the first trimester, before any clinical signs and symptoms appeared, developed gestational hypertension at term. We also found that the level of corin, an atrial natriuretic peptide-converting enzyme, was increased in the maternal circulation, especially during late pregnancy, as a homeostatic response to elevated sympathetic activity.

CONCLUSION

These findings provide important insight into the neural mechanisms underlying hypertensive disorders during pregnancy. With this knowledge, early prevention or treatment targeted to the appropriate pathophysiology may be initiated, which may reduce maternal and fetal death or morbidity, as well as cardiovascular risks in women later in life.

Multiparity is associated with poorer cardiovascular health among women from the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Multiparity is associated with a greater risk of incident cardiovascular disease. However, the relationship of parity with cardiovascular health, as measured by the American Heart Association Life's Simple 7 metrics, is uncertain.

OBJECTIVE

We aimed to examine the association between parity and ideal cardiovascular health among 3430 women, aged 45-84 years, free of clinical cardiovascular disease enrolled in the Multi-Ethnic Study of Atherosclerosis.

STUDY DESIGN

The Multi-Ethnic Study of Atherosclerosis is a prospective cohort study that recruited middle-aged to older women and men from 6 centers in the United States between 2000 and 2002. The study population comprised 38% White, 28% Black, 23% Hispanic, and 11% Chinese American subjects. Parity (total number of live births) was self-reported and categorized as 0, 1-2, 3-4 and ≥5. The Life's Simple 7 metrics, defined according to American Heart Association criteria, include health behaviors (smoking, physical activity, body mass index, diet) and health factors (blood pressure, total cholesterol, and blood glucose). We categorized each metric into ideal (2 points), intermediate (1 point), and poor (0 points). A total cardiovascular health score of 0-8 was considered inadequate; 9-10, average; and 11-14, optimal. We used multinomial logistic regression to examine the cross-sectional association between parity and the cardiovascular health score, adjusted for sociodemographics, field site, hormone therapy, and menopause.

RESULTS

The mean (standard deviation) age was 62 (10) years. The mean (standard deviation) cardiovascular health score was lower with higher parity (8.9 [2.3], 8.7 [2.3], 8.5 [2.2], and 7.8 [2.0] for 0, 1-2, 3-4, and ≥5 live births, respectively). In comparison to inadequate cardiovascular health scores, the adjusted odds of average cardiovascular health scores were significantly lower for all parity categories relative to nulliparity (prevalence odds ratios [OR] for parity of 1-2, 0.64 [95% confidence interval 0.49-0.83]; 3-4, 0.65 [0.49-0.86]; ≥5, 0.64 [0.45-0.91]). Women with ≥5 live births had a lower prevalence of optimal cardiovascular health scores (OR 0.50 [0.30-0.83]). In the fully adjusted models, the association between parity and each Life's Simple 7 metric was only statistically significant for body mass index. Women with ≥5 live births had lower prevalence of ideal body mass index (OR 0.52 [0.35-0.80]). In addition, the test for interaction showed that the association between parity and cardiovascular health was not modified by race/ethnicity (P = .81 for average cardiovascular health scores and P = .20 for optimal cardiovascular health scores).

CONCLUSION

Multiparity was associated with poorer cardiovascular health, especially for women with ≥5 live births. More research is required to explore the mechanisms by which parity may worsen cardiovascular health.

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.

Abnormally expressed miR-23b in Chinese Mongolian at high cardiovascular risk may contribute to monocyte/macrophage inflammatory reaction in atherosclerosis

Background: The prevalence of coronary heart disease (CHD) appears to be high among Chinese Mongolians. MiR-23b has been proven to play a key role in atherosclerosis. The expression and role of miR-23b in the Mongolians at high cardiovascular risk were explored in the present study.

Methods: Forty cases of blood samples from the Mongolians at high cardiovascular risk were enrolled in the present study. The expression of miR-23b was quantified by quantitative real-time PCR. To induce monocytes differentiation into macrophages, HP-1 cells were cultured with phorbol 12-myristate 13-acetate. The level of inflammatory markers was determined by the enzyme-linked immunosorbent assay. The interaction between miR-23b and A20 was explored by the dual luciferase reporter assay.

Results: The expression of miR-23b in the Mongolian at high cardiovascular risk was higher than that in healthy Mongolian volunteers. Decrease in ATP-binding cassette transporter A1 caused by miR-23b is responsible for TC accumulation in the Mongolian at high cardiovascular risk. MiR-23b enhanced the oxidized low-density lipoprotein (oxLDL)-induced inflammatory response of THP-1 derived macrophage. MiR-23b regulated nuclear factor-κB (NF-κB) pathway through targeting A20. MiR-23b mediated oxLDL-induced inflammatory response of peripheral blood mononuclear cell in the Mongolian at high cardiovascular risk.

Conclusion MiR-23b enhanced oxLDL-induced inflammatory response of macrophages in the Mongolian at high cardiovascular risk through the A20/NF-κB signaling pathway, and thus contributing to atherosclerosis.

U-shaped association between fertility and mortality in a community-based sample of Japanese women

BACKGROUND

Prospective cohort studies of contemporary populations in both Western and Asian settings have reported a U-shaped association between fertility and mortality. We examined whether an association exists between fertility and all-cause and cause-specific mortality in a sample of Japanese women.

METHODS

A prospective cohort study was conducted in one rural and one urban community in Gunma Prefecture, Japan, in 1993. A follow-up survey was conducted in the year 2000 in 4858 women aged 47-77 years, and information on demographic and lifestyle characteristics was collected. Mortality and migration data through December 2008 were obtained. A Cox proportional hazard model was used to examine the relationship between parity and mortality.

RESULTS

Compared with women with 2-4 children (reference group), higher total mortality was observed among women with 0-1 or 5+ children. Low (HR 1.7, 95% CI 1.2 to 2.3) and high (HR 2.1, 95% CI 1.0 to 4.7) parities were both associated with higher all-cause mortality even after adjusting for potential confounders. Mortality due to ischaemic heart disease exhibited a significant association with parity; the HRs were 3.2 (95% CI 1.1 to 9.2) for women with 0-1 child and 8.7 (95% CI 1.7 to 45.5) for women with 5 or more children. No significant association was observed for mortality from malignancies, cancer of the digestive system, cardiovascular disease or cerebrovascular disease.

CONCLUSIONS

There exists a U-shaped association between parity and all-cause mortality and cause-specific mortality due to ischaemic heart disease among Japanese women.

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

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