Childbearing history and late-life mortality: the Dubbo study of Australian elderly

Child rearing or childbearing? Risk of cardiovascular diseases associated to parity and number of children

BACKGROUND

An increased risk of cardiovascular diseases (CVD) has been associated with women's parity, but whether or not this association reflects a direct pregnancy effect, or exposure to factors related to childrearing, still appears unclear. We assessed the CVD risk associated with number of children separately by gender and tested effect modification by socioeconomic position (SEP) and employment status, in order to elucidate the possible mechanisms underlying this association.

METHODS

The study population was composed of 20,904 men and 25,246 women who were interviewed in one of two National Health Surveys conducted in 2000 and 2005 in Italy. These subjects were followed for CVD incidence up to 2014 through record-linkage with national archives of mortality and hospitalisations. CVD risk was estimated by Cox regression models that were adjusted for socio-demographics, perceived health, lifestyles, biological CVD risk factors and for other potential confounders.

RESULTS

CVD incidence was significantly increased among men with 3 or more children (HR = 1.26, 95% CI: 1.02-1.56) and among women with 2 and with 3 or more children (HR = 1.42, 95% CI: 1.10-1.83; and HR = 1.39, 95% CI: 1.03-1.87, respectively) compared to subjects without children and no significant gender differences were observed. Subjects with lower SEP displayed stronger associations with parity and a higher number of children for both genders; by contrast, no modifying effect of employment status was observed.

CONCLUSIONS

Taken together, the significant association between higher parity and CVD risk in both genders, and the higher risk of CVD associated with higher parity among lower SEP parents, suggests that childrearing has a potential effect on the development of CVD that is more pronounced among disadvantaged families, although a concurrent effect of childbearing cannot be completely excluded.

Impact of fertility on the longevity of older rural Chinese women: an analysis of a longitudinal survey

Background

This study evaluates the impact of fertility during the childbearing period on the longevity of older rural Chinese women and verifies whether any trade-off exists between women’s longevity and their number of children to provide empirical evidence for improving health intervention policies and formulating active fertility policies in low-fertility countries.

Methods

Based on the data of the deaths of 1623 older adults aged 65 and above during 2014–2018 in the Chinese Longitudinal Healthy Longevity Survey, this study explores the relationship between the number of children born and older rural women’s longevity using the ordinary least squares method. Furthermore, the impact of fertility on the longevity of men and women in rural and urban areas, along with other reproductive behaviours on older rural women’s longevity, were analysed.

Results

There was a significant negative correlation between the number of children born and women’s longevity (β = − 0.555, p < 0.05). Additionally, their longevity exhibited a decreasing trend with having birthed more sons and an increasing trend with more daughters. Age at first and last births had a significant positive relationship with rural women’s longevity; however, the effect of fertility on the longevity of older rural and urban men and older urban women was not significant.

Conclusions

It is confirmed that there is a trade-off between fertility and longevity for rural women in China. Future research should focus on compensating for the decline in female longevity caused by the number of children born and promote the concept of a healthy pregnancy, scientific nurture, and gender equality in fertility.

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.

Childbearing and mortality among women with personality disorders: nationwide registered-based cohort study

BACKGROUND

People with a personality disorder have a higher mortality and reduced life expectancy than the general population. Childbearing is thought to have a protective effect on morbidity and mortality. Yet, there are no studies on whether childbearing is related to a lower mortality among women with personality disorder.

AIMS

This study examined associations between childbearing and mortality among women with personality disorder. Our hypothesis was that parity would be associated with lower mortality.

METHOD

This register-based cohort study included 27 412 women treated for personality disorder in in-patient or specialised out-patient care between 1990 and 2015. We used nationwide population-based registers to obtain information on sociodemographics, child delivery, healthcare use and mortality. Mortality risk estimates were calculated as hazard ratios (HRs) with 95% CIs using Cox regression. Adjustments were made for year of birth, educational level, age at diagnosis, comorbidity and severity of personality disorder.

RESULTS

Nulliparous women had a nearly twofold increased mortality risk (adjusted HR = 1.78, 95% CI 1.50-2.12) compared with parous women and over twofold mortality risk (adjusted HR = 2.29, 95% CI 1.72-3.04) compared with those giving birth after their first personality disorder diagnosis. Those giving birth before their first personality disorder diagnosis had a 1.5-fold higher risk of mortality than those giving birth after their first personality disorder diagnosis (adjusted HR = 1.48, 95% CI 1.06-2.07). There was a threefold risk of suicide in nulliparous women compared with those giving birth after their first personality disorder diagnosis (adjusted HR = 2.90, 95% CI 1.97-4.26).

CONCLUSIONS

Childbearing history should be an integral part of the clinical evaluation of women with personality disorder.

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.

Infertility and mortality

BACKGROUND

Infertility affects 1 in 10 American reproductive-age women. The impact of this disease beyond the reproductive years is largely unknown.

OBJECTIVE

The objective of the study was to determine the association of infertility history with all-cause and cause-specific mortality.

STUDY DESIGN

This secondary analysis of a multicenter randomized clinical trial included 75,784 women (aged 55-74 years) prospectively enrolled in the Prostate, Lung, Colorectal, and Ovarian cancer-screening trial from 1992 through 2001 and followed up a minimum of 10 years for health-related outcomes and death (856,935 person-years). We examined the association of infertility history (inability to conceive for 1 year or greater) of all-cause and cause-specific mortality using disease risk score-adjusted Cox-proportional hazard regression models.

RESULTS

Infertile women had a 10% increased risk of death (from any cause) during the study period compared with the unexposed (adjusted hazard risk, 1.10, 95% confidence interval, 1.02-1.18, P = .010). This effect was predominantly noted in women at an otherwise low risk of mortality who had a 26% increased risk of death (adjusted hazard risk, 1.26, 95% confidence interval, 1.12-1.42, P < .001). No differences in cardiovascular or diabetic mortality were noted. The risk of cancer death at any time over the study period was increased by 23% in infertile women compared with the unexposed (adjusted hazard risk, 1.23, 95% confidence interval, 1.10-1.37, P < .001). This effect was predominantly noted in women at an otherwise low risk of cancer mortality who had a 47% increased risk of cancer death (adjusted hazard risk, 1.47, 95% confidence interval, 1.25-1.73, P < .001). While no differences are seen in the risk of death from endometrial or ovarian cancer, the risk of death from breast cancer was more than doubled in infertile women at an otherwise low risk of breast cancer death compared with the unexposed (adjusted hazard risk, 2.64, 95% confidence interval, 1.71-4.08, P < .001).

CONCLUSION

Infertility is a harbinger of future morbidity and mortality. Infertile women are at an increased risk of all-cause and cancer-related mortality. Consideration of infertility history in health care maintenance presents an opportunity for screening and early intervention for long-term health outcomes.

Association of Parenthood With Incident Heart Disease in United States' Older Men and Women: A Longitudinal Analysis of Health and Retirement Study Data

Objective: To examine the association of number of children birthed/fathered with incident heart disease, accounting for socioeconomic and lifestyle characteristics. Methods: We analyzed data from 24,923 adults 50 and older (55% women) in the Health and Retirement Study. Participants self-reported number of children and doctor-diagnosed incident heart disease. Cox proportional hazards models estimated heart disease risk. Results: Compared to women with one to two children, those with five or more had increased risk of heart disease (hazard ratio [HR] = 1.13, 95% confidence interval [CI] = [1.03, 1.25]). Compared to men with one to two children, those with five or more had a marginally increased risk of heart disease (HR = 1.11, 95% CI = [0.99, 1.25]), but this association attenuated in models adjusting for socioeconomic and lifestyle variables. Compared to men with no children, those with five or more retained a borderline significant association in the fully adjusted model (HR = 1.15, 95% CI = [0.99, 1.35]). Discussion: Social and lifestyle pathways appear to link parenthood to cardiovascular health.

Infertility: a marker of future health risk in women?

Infertility, may be a harbinger for future health risk in women, including early mortality. Fertility status itself could serve as an early biomarker, (present in a woman's reproductive years) for risk stratification later in life. The relationship between infertility and early mortality involves the impact of nulliparity on future adverse health events, potential sequelae from the underlying cause(s) of infertility, the risks of fertility treatments, as well as the potential for risk reduction from a healthy pregnancy. This complex interplay coupled with difficulties ascertaining infertility on a population level has presented unique challenges to assessing infertility and early mortality risk. With further study, a better understanding the role of fertility status in health at various stages of life may provide unique opportunities for surveillance and risk reduction.

Number of Offspring and Cardiovascular Disease Risk in Men and Women: The Role of Shared Lifestyle Characteristics

Supplemental Digital Content is available in the text.

Background:

Previous studies of the number of offspring and cardiovascular disease (CVD) report conflicting findings. We re-examined this association in both sexes to clarify the role of the cardiometabolic changes that women experience during pregnancy versus shared lifestyle characteristics.

Methods:

We studied 180,626 women and 133,259 men participating in the UK Biobank cohort who were free of CVD at baseline. CVD events were obtained from hospital and death registers. Analyses were conducted using Cox proportional hazards regression.

Results:

The incidence rates of overall CVD were six per 1000 person-years for women and nine per 1000 person-years for men. Number of children showed an association with risk of CVD among women; the adjusted HR (95% CI) was 1.2 (1.1, 1.3) for one, 1.1 (1.0, 1.2) for two, 1.2 (1.1, 1.3) for three, and 1.2 (1.1, 1.4) for four or more as compared to none. Number of children was also associated with CVD among men; the adjusted HR (95% CI) was 1.1 (1.0, 1.2) for one, 1.0 (0.96, 1.1) for two, 1.1 (1.0, 1.2) for three, and 1.1 (1.0, 1.3) for four or more as compared to none. There was no evidence of heterogeneity in the associations between sexes (P_interaction = 0.80). Number of offspring also showed similar associations with ischemic heart disease and hypertensive disorders in both sexes.

Conclusions:

We observed similar associations between number of offspring and CVD in both sexes. The association among women might therefore be largely explained by unobserved behavioral and lifestyle characteristics.

Mortality and causes of death among women with a history of placental abruption

INTRODUCTION

Women with a history of placental abruption have an increased later morbidity, but not much is known of the later mortality.

MATERIAL AND METHODS

Data on women with placental abruption (index cohort) between 1969 and 2005 (n = 7805) were collected from the Finnish Hospital Discharge Register and the Finnish Medical Birth Register. A matched reference cohort consisted of women without placental abruption (n = 23 523). The causes of death were retrieved from the Cause-of-Death Register. Cause-specific mortality was compared by hazard ratios (HR). Standardized mortality ratios were calculated to compare both cohorts with the general female population. The main outcome measure was subsequent mortality.

RESULTS

By the end of 2013 there were 395 deaths in the index cohort and 863 deaths in the reference cohort. The overall mortality was increased in the index cohort compared with the reference cohort [HR 1.39, 95% confidence interval (CI) 1.24-1.57]. The index cohort had an increased risk of death from respiratory tract malignancies (HR 1.72, 95% CI 1.05-2.82), alcohol-related causes (HR 1.84, 95% CI 1.25-2.72), and external causes (HR 1.63, 95% CI 1.19-2.22), especially suicide (HR 1.71, 95% CI 1.07-2.74). The mortality from cardiovascular diseases did not differ. The standardized mortality ratio was increased in the index cohort compared with the general Finnish female population (HR 1.13, 95% CI 1.02-1.24), especially for respiratory tract malignancies (HR 1.79, 95% CI 1.16-2.64). The index cohort women tended to die younger than referent women (p < 0.001).

CONCLUSIONS

Overall mortality among women with a history of placental abruption is increased. These women tend to die younger than referent women do.

MECHANISMS IN ENDOCRINOLOGY: Parity and risk of type 2 diabetes: a systematic review and dose-response meta-analysis

OBJECTIVE

Epidemiologic studies regarding the association between parity and risk of type 2 diabetes have yielded inconsistent results. Therefore, we performed a systematic review and dose-response meta-analysis to determine the relation between parity and type 2 diabetes risk.

METHODS

We searched PubMed and Embase for published epidemiologic studies that assessed the relation between parity and risk of type 2 diabetes up to 31 March 2016. A dose-response random-effects model was used to combine study-specific relative risks (RRs) and 95% confidence intervals (CIs). Potential sources of heterogeneity were explored by meta-regression and subgroup analyses.

RESULTS

Seven cohort studies, 1 case-control study and 9 cross-sectional studies including 296 923 participants were eligible for inclusion. The combined RR for the highest versus lowest category of parity indicated a 54% increment in type 2 diabetes risk (95% CI: 29-83%). In the cubic spline model, a nonlinear association was found between parity and risk of type 2 diabetes (P = 0.02 for nonlinearity). Compared with nulliparous women, the estimated RR (95% CI) of type 2 diabetes for women with one to seven children was 1.01 (0.96-1.07), 1.08 (1.00-1.16), 1.20 (1.12-1.30), 1.32 (1.22-1.42), 1.37 (1.27-1.48), 1.39 (1.26-1.52) and 1.39 (1.23-1.57) respectively.

CONCLUSIONS

Higher parity is significantly associated with an increased risk of type 2 diabetes. Further studies are warranted to fully adjust for the potential confounders and explore the causality between parity and type 2 diabetes risk.

Parity, coronary heart disease and mortality in the old order Amish

BACKGROUND AND AIMS

Prior data on the association between parity and mortality are limited by the presence of sociodemographic confounders including cultural norms of parity. Our objective was to determine the association between parity and mortality in the Amish, a socioeconomically homogenous group with large numbers of children per family.

METHODS

We conducted a population-based cohort study among 518 Old Order Amish women enrolled in a cardiovascular awareness program. The mean length of follow-up for mortality was 13.52 years. We determined the adjusted associations between parity and obesity, prevalent coronary heart disease and mortality.

RESULTS

The mean number of total births per woman was 6.7 ± 3.6 with a mode of 8. No significant association was observed between parity and all-cause mortality when adjusted for age (HR 1.00 per additional birth; 95% CI 0.96-1.05; p = 0.85) or in multivariate analysis (HR 1.00, 95% CI 0.95-1.05; p = 0.95). There was also no association of parity in age- or multivariable adjusted models with prevalent diabetes, hypertension or coronary heart disease. Despite the lack of effect of parity on mortality, a significant association of ten or more births was observed with higher body mass index (BMI) compared to the referent group of 8-9 total births.

CONCLUSIONS

In a highly homogeneous population with high rates of parity, no association between overall mortality and parity was observed. Ten or more births were significantly associated with a higher BMI but not with overall mortality.

Parity and All-cause Mortality in Women and Men: A Dose-Response Meta-Analysis of Cohort Studies

To quantitatively assess the association between parity and all-cause mortality, we conducted a meta-analysis of cohort studies. Relevant reports were identified from PubMed and Embase databases. Cohort studies with relative risks (RRs) and 95% confidence intervals (CIs) of all-cause mortality in three or more categories of parity were eligible. Eighteen articles with 2,813,418 participants were included. Results showed that participants with no live birth had higher risk of all-cause mortality (RR= 1.19, 95% CI = 1.03–1.38; I² = 96.7%, P < 0.001) compared with participants with one or more live births. Nonlinear dose-response association was found between parity and all-cause mortality (P for non-linearity < 0.0001). Our findings suggest that moderate-level parity is inversely associated with all-cause mortality.

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

Parity has been shown to inversely associate with cardiovascular disease (CVD) mortality, but the evidence of epidemiological studies is still controversial. Therefore, we quantitatively assessed the relationship between parity and CVD mortality by summarizing the evidence from prospective studies. We searched MEDLINE (PubMed), EMBASE and ISI Web of Science databases for relevant prospective studies of parity and CVD mortality through the end of March 2015. Fixed- or random-effects models were used to estimate summary relative risks (RRs) and 95% confidence intervals (CIs). Heterogeneity among studies was assessed using the I² statistics. All statistical tests were two-sided. Ten prospective studies were included with a total of 994,810 participants and 16,601 CVD events. A borderline significant inverse association was observed while comparing parity with nulliparous, with summarized RR = 0.79 (95% CI: 0.60–1.06; I² = 90.9%, P < 0.001). In dose-response analysis, we observed a significant nonlinear association between parity number and CVD mortality. The greatest risk reduction appeared when the parity number reached four. The findings of this meta-analysis suggests that ever parity is inversely related to CVD mortality. Furthermore, there is a statistically significant nonlinear inverse association between parity number and CVD mortality.

Immune Sensitization and Mortality in Wait-Listed Kidney Transplant Candidates

Cardiovascular mortality is the leading cause of death in ESRD. Whereas innate and adaptive immunity have established roles in cardiovascular disease, the role of humoral immunity is unknown. We conducted a retrospective cohort study in first-time adult kidney transplant candidates (N=161,308) using data from the Scientific Registry of Transplant Recipients and the Centers for Medicare and Medicaid Services to evaluate whether anti-human leukocyte antigen antibodies, measured as panel reactive antibodies (PRAs), are related to mortality in ESRD. Relationships between time-varying PRAs and all-cause or cardiovascular mortality were assessed using Cox proportional hazards models. The analysis was repeated in subcohorts of candidates at lower risk for significant comorbidities, activated on the waiting list after 2007, or unsensitized at activation. Competing risks analyses were also conducted. Fully adjusted models showed increased hazard ratios (HRs [95% confidence intervals]) for all-cause mortality (HR, 1.02 [95% CI, 0.99 to 1.06]; HR, 1.11 [95% CI,1.07 to 1.16]; and HR,1.21 [95% CI,1.15 to 1.27]) and cardiovascular mortality (HR, 1.05 [95% CI,1.00 to 1.10]; HR,1.11 [95% CI,1.05 to 1.18]; and HR,1.21 [95% CI,1.12 to 1.31]) in PRA 1%-19%, PRA 20%-79%, and PRA 80%-100% categories compared with PRA 0%, respectively. Associations between PRA and the study outcomes were accentuated in competing risks models and in lower-risk patients and persisted in other subcohorts. Our findings suggest that PRA is an independent predictor of mortality in wait-listed kidney transplant candidates. The mechanisms by which PRA confers an incremental mortality risk in sensitized patients, and the role of transplantation in modifying this risk, warrant further study.

Male microchimerism and survival among women

BACKGROUND

During pregnancy, woman and fetus exchange small quantities of cells, and their persistence at later times is termed microchimerism. Microchimerism is known to substantially impact on women's later health. This study examined the survival of women according to male microchimerism status.

METHODS

Male microchimerism presence, measured as Y chromosome in peripheral blood samples, was determined in 272 women from the large Danish Diet, Cancer and Health cohort when aged 50-64 years during 1993-97. Women were followed up for cause-specific death in national Danish registers until the end of 2009. Survival was analysed using Cox regression.

RESULTS

A total of 190 women (70%) were male microchimerism positive. During follow-up 21 women died, of whom 11 (52%) were male microchimerism positive at enrolment and 10 were negative. Of the 21 deaths, 13 (62%) were due to cancer and 5 (24%) were due to cardiovascular disease. Male microchimerism presence was associated with a reduced hazard ratio of all-cause mortality of 0.42 (95% CI 0.17-1.03). The hazard ratio of death from cancer and cardiovascular disease was 0.24 (95% CI 0.08-0.79) and 1.66 (95% CI 0.18-15.48), respectively, among male microchimerism positive compared with negative women.

CONCLUSIONS

Although the biological mechanisms are not precisely known, male microchimerism presence in peripheral blood of women is associated with substantially improved survival in women. The results also indicate that the association with male microchimerism may vary between different causes of death.