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

Survival costs and benefits of reproduction: A register-based study in 20th century Estonia

Patterns of individual variation in lifespan and senescence depend on the associations between parental survival and reproductive rates. We studied the associations between parity and survival among 579,271 Estonians born between 1905 and 1945 and in a cohort with a completed lifespan born in 1905-1927. For this cohort, selection for increased lifespan operated on both sexes, but it was stronger in men than in women. However, the median lifespan increased between the subsequent cohorts in women but stagnated in men. Selection for longer lifespan was caused by the below-average lifespan of individuals with no or single offspring. Despite a general positive selection for lifespan, survival costs of reproduction were also detected among a relatively small proportion of individuals with high parities, as mothers of two and fathers of two and three children had the highest median lifespans. Fathers of more than six children had better survival than fathers of few children in their reproductive age, but this association reversed after age 70. The reversal of this association between survival and parity at old age indicates that relative mortality risks between those with lower versus higher parities change across ages, as predicted by the antagonistic pleiotropy theory of aging.

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.

Association between number of children and incident heart disease and stroke in parents - results from the Survey of Health, Ageing and Retirement in Europe (SHARE)

BACKGROUND

In former studies, parity was associated with adverse cardiovascular outcomes in parents. This study aims to extend the limited existing data regarding the association between the number of children and heart disease and/or stroke in a large longitudinal study in different European countries in both men and women.

METHODS

For 42 075 subjects (18 080 men, 23 995 women; median age 58 years (interquartile range: 53 to 65)) from 19 European countries and Israel in the Survey of Health, Ageing and Retirement in Europe (SHARE), odds ratios (OR) for the association between number of children and incident self-reported heart disease and/or stroke (HDS) were estimated using logistic regression analyses. Persons with one or two children were used as reference. The final model was adjusted for baseline age, sex, education, region, and marital status. All analyses were stratified by sex.

RESULTS

Women with seven or more children had the highest OR for the association between the number of children and incident HDS (OR = 2.12 [95% CI: 1.51 to 2.98]), while men with six children showed the highest OR (OR = 1.62 [1.13 to 2.33]). Stratified by education, across all education levels, men and women with five or more children had the highest ORs for this association. The highest OR was observed in both women and men in the group with primary education (OR = 1.66 [1.29 to 2.15] and OR = 1.60 [1.19 to 2.14], respectively). Stratified by region, both men and women with five or more children showed the highest ORs in Southern Europe (OR = 2.07 [1.52 to 2.82] and OR = 1.75 [1.25 to 2.44], respectively).

CONCLUSION

In this long-term follow-up study in various countries in Europe and Israel we found a positive association between number of children and incident HDS. This association was more pronounced in lower educated subjects and showed regional variations.

Cardiovascular health in the menopause transition: a longitudinal study of up to 3892 women with up to four repeated measures of risk factors

BACKGROUND

Women experience adverse changes in cardiovascular health in mid-life; whether the menopausal transition influences these remains strongly debated. The aim of this study was to examine associations of reproductive age (time since final menstrual period (FMP)) with change in carotid intima media thickness (CIMT) and cardiovascular risk factors and determine the role of chronological and reproductive age.

METHODS

We used data from 1702 women from a pregnancy-based UK cohort who had up to four repeat cardiovascular health measures between mean age 51 (SD = 4.0) and 56 (SD = 3.6) years and experienced a natural menopause. Multilevel models were used to assess the relationship between cardiovascular measures and time since FMP (reproductive age), whilst adjusting for the underlying effects of chronological age and confounders (socioeconomic factors, body mass index, smoking, alcohol, parity, age at menarche). In addition, we looked at the relationship between cardiovascular measures by chronological age according to menopausal stages (pre-menopause, peri-menopause and post-menopause) using information from women who had and had not experienced menopause (N = 3892).

RESULTS

There was no strong evidence that reproductive age was associated with CIMT (difference in mean 0.8 μm/year, 95% CI - 0.4, 2.1), whereas there was a strong positive association of chronological age (7.6 μm/year, 95% CI 6.3, 8.9). Consistent with this, we found weaker linear associations of reproductive compared with chronological age for atherosclerotic risk factors, such as with systolic blood pressure (- 0.1 mmHg/year, 95% CI - 0.3, 0.1, and 0.4 mmHg/year, 95% CI 0.2, 0.5, respectively) and non-HDL-cholesterol (0.02 mmol/l/year, 95% CI 0.005, 0.03, and 0.06, 95% CI 0.04, 0.07, respectively). In contrast, associations with fat mass (0.06 kg/m2/year, 95% CI 0.03, 0.10, and 0 kg/m2/year, 95% CI - 0.04, 0.04, respectively) and C-reactive protein (0.01, 95% CI 0.001, 0.02, and 0.01, 95% CI - 0.001, 0.02 natural logged mg/l/year, respectively) were stronger for reproductive compared with chronological age. Both reproductive and chronological age were (weakly) positively associated with glucose (0.002, 95% CI 0.0001, 0.003, and 0.002, 95% CI 0.0001, 0.003 natural logged mmol/l/year, respectively).

CONCLUSIONS

Our results suggest that going through the menopausal transition does not further increase women's risk of atherosclerosis (measured by CIMT) beyond effects of ageing. Menopausal transition may, in additional to ageing, modestly increase adiposity and glucose levels and therefore a possible associated diabetes risk.

Gender-related factors and out-of-hospital cardiac arrest incidence in women and men: analysis of a population-based cohort study in the Netherlands

BACKGROUND

The incidence of out-of-hospital cardiac arrest (OHCA) differs consistently between women and men. Besides sex-related (biological) factors, OHCA risk may relate to gender-related (sociocultural) factors. We explored the association of selected gender-related factors with OHCA incidence in women and men.

METHODS

We combined data on emergency medical services-attended OHCA with individual-level data from all women and men aged ≥25 years living in North Holland, the Netherlands. We estimated the associations between employment status, primary earner status, living with children and marital status and the OHCA incidence with Cox proportional hazards models stratified by sex and adjusted for age and socioeconomic status. To determine if metabolic factors explain the associations, we added hypertension, diabetes mellitus and dyslipidaemia to the models. Population attributable fractions (PAF) for all gender-related factors were calculated.

RESULTS

All four gender-related factors were associated with OHCA incidence (eg, unemployed vs employed; HR 1.98, 95% CI 1.67 to 2.35 in women; HR 1.60, 95% CI 1.44 to 1.79 in men). In both sexes, those unemployed, those who are not primary earners, those living without children, and married or divorced individuals had an increased OHCA risk. The PAF ranged from 4.9 to 40.3 in women and from 4.4 to 15.5 in men, with the highest PAF for employment status in both sexes. Metabolic risk factors did not explain the observed associations.

CONCLUSION

Gender-related factors were associated with risk of OHCA and contributed substantially to the OHCA burden at the population level, particularly in women. Employment status contributed most to the OHCA burden.

Risk factors for incident cardiovascular events among adults in low- and middle-income countries: A systematic review and meta-analysis of prospective cohort studies

The relative contributions of risk factors for cardiovascular events at a population level has received little attention in low- and middle-income countries (LMICs). We estimated the population attributable fraction (PAF) of risk factors associated with incident cardiovascular events in LMICs. We searched six databases for relevant articles, supplemented with a manual search of reference lists. Articles included in the meta-analyses were those based on prospective community-based cohorts and incorporating adjusted hazard ratios (HR) or relative risks with 95% confidence intervals (95% CI) for associations between risk factors and a composite cardiovascular and/or stroke endpoint. Pooled HRs and 95% CI were calculated using the random effects model. We assessed heterogeneity using the I² test and study quality using the Newcastle-Ottawa Scale. We calculated the PAF of each associated risk factor. The protocol was registered in PROSPERO (CRD42019122741). We identified 18 cohorts from LMICs with 1,125,846 participants, 77,045 composite cardiovascular events and 42,216 strokes. Substantial proportions of incident cardiovascular events were attributable to hypertension (HR [95% CI], 2.23 [2.01-2.48], PAF = 28%); current smoking (1.44 [1.31-1.58], PAF = 10%); and diabetes mellitus (1.93 [1.67-2.23], PAF = 8%). Other risk factors identified included number of children, depression, bone mineral density, and air pollution. A substantial proportion of incident cardiovascular events were linked to traditional metabolic and behavioural modifiable risk factors. However, other novel risk factors also appear to contribute. Targeting of these established and novel risk factors has the potential to reduce the burden of CVD in LMICs.

Pregnancy, preeclampsia and maternal aging: From epidemiology to functional genomics

Women live longer than men but experience greater disability and a longer period of illness as they age. Despite clear sex differences in aging, the impact of pregnancy and its complications, such as preeclampsia, on aging is an underexplored area of geroscience. This review summarizes our current knowledge about the complex links between pregnancy and age-related diseases, including evidence from epidemiology, clinical research, and genetics. We discuss the relationship between normal and pathological pregnancy and maternal aging, using preeclampsia as a primary example. We review the results of human genetics studies of preeclampsia, including genome wide association studies (GWAS), and attempted to catalog genes involved in preeclampsia as a gateway to mechanisms underlying an increased risk of later life cardio- and neuro- vascular events. Lastly, we discuss challenges in interpreting the GWAS of preeclampsia and provide a functional genomics framework for future research needed to fully realize the promise of GWAS in identifying targets for geroprotective prevention and therapeutics against preeclampsia.

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.

Association between Number of Siblings and Cardiovascular Risk Factors in Childhood and in Adulthood: The Cardiovascular Risk in Young Finns Study

OBJECTIVE

To determine the association of number of siblings on cardiovascular risk factors in childhood and in adulthood.

STUDY DESIGN

In total, 3554 participants (51% female) from the Cardiovascular Risk in Young Finns Study with cardiovascular disease risk factor data at baseline 1980 (age 3-18 years) and 2491 participants with longitudinal risk factor data at the 2011 follow-up. Participants were categorized by number of siblings at baseline (0, 1, or more than 1). Risk factors (body mass index, physical activity, hypertension, dyslipidemia, and overweight, and metabolic syndrome) in childhood and in adulthood were used as outcomes. Analyses were adjusted for age and sex.

RESULTS

In childhood, participants without siblings had higher body mass index (18.2 kg/m², 95% CI 18.0-18.3) than those with 1 sibling (17.9 kg/m², 95% CI 17.8-18.0) or more than 1 sibling (17.8 kg/m², 95% CI 17.7-17.9). Childhood physical activity index was lower among participants without siblings (SD -0.08, 95% CI -0.16-0.00) compared with participants with 1 sibling (SD 0.06, 95%CI 0.01-0.11) or more than 1 sibling (SD -0.02, 95% CI -0.07-0.03). OR for adulthood hypertension was lower among participants with 1 sibling (OR 0.73, 95% CI 0.54-0.98) and more than 1 sibling (OR 0.71, 95% CI 0.52-0.97) compared with participants with no siblings. OR for obesity was lower among participants with 1 sibling (OR 0.72, 95% CI 0.54-0.95) and more than 1 sibling (OR 0.75, 95% CI 0.56-1.01) compared with those with no siblings.

CONCLUSIONS

Children without siblings had poorer cardiovascular risk factor levels in childhood and in adulthood. The number of siblings could help identify individuals at increased risk that might benefit from early intervention.

The effect of bearing and rearing a child on blood pressure: a nationally representative instrumental variable analysis of 444611 mothers in India

BACKGROUND

At the individual level, it is well known that pregnancies have a short-term effect on a woman's cardiovascular system and blood pressure. The long-term effect of having children on maternal blood pressure, however, is unknown. We thus estimated the causal effect of having children on blood pressure among mothers in India, a country with a history of high fertility rates.

METHODS

We used nationally representative cross-sectional data from the 2015-16 India National Family and Health Survey (NFHS-4). The study population comprised 444 611 mothers aged 15-49 years. We used the sex of the first-born child as an instrumental variable (IV) for the total number of a woman's children. We estimated the effect of an additional child on systolic and diastolic blood pressure in IV (two-stage least squares) regressions. In additional analyses, we stratified the IV regressions by time since a mother last gave birth. Furthermore, we repeated our analyses using mothers' husbands and partners as the regression sample.

RESULTS

On average, mothers had 2.7 children [standard deviation (SD): 1.5], a systolic blood pressure of 116.4 mmHg (SD: 14.4) and diastolic blood pressure of 78.5 mmHg (SD: 9.4). One in seven mothers was hypertensive. In conventional ordinary least squares regression, each child was associated with 0.42 mmHg lower systolic [95% confidence interval (CI): -0.46 to -0.39, P < 0.001] and 0.13 mmHg lower diastolic (95% CI: -0.15 to -0.11, P < 0.001) blood pressure. In the IV regressions, each child decreased a mother's systolic blood pressure by an average of 1.00 mmHg (95% CI: -1.26 to -0.74, P < 0.001) and diastolic blood pressure by an average of 0.35 mmHg (95% CI: -0.52 to -0.17, P < 0.001). These decreases were sustained over more than a decade after childbirth, with effect sizes slightly declining as the time since last birth increased. Having children did not influence blood pressure in men.

CONCLUSIONS

Bearing and rearing a child decreases blood pressure among mothers in India.

Maternal depression and loss of children under the one-child family planning policy in China: a cross-sectional study of 300 000 women

OBJECTIVES

This study aims to explore the association between maternal depression and the loss of the only child under the family-planning (FP) policy.

DESIGN

Cross-sectional data from a Chinese population-based study were analysed.

SETTING

Population from 10 (5 rural and 5 urban) areas in China.

PARTICIPANTS

Around 300 000 females were included in the study. The FP group was defined as women with one or two live births. Those with no surviving child were classified into the loss-of-only-child group. The non-FP group included women who had more than two live births. Logistic regression was used to assess the relationship between major depressive disorder (MDD) and family types, after stratification and adjustment.

OUTCOME

MDD was assessed using the Composite International Diagnostic Inventory.

RESULTS

The odds of MDD are 1.42 times higher in the FP group in general (OR=1.42, 95% CI: 1.28 to 1.57), as opposed to the non-FP group. In particular, the odds of MDD are 1.36 times greater in the non-loss-of-only-child group (OR=1.36, 95% CI: 1.21 to 1.51) and 2.80 (OR=2.80, 95% CI: 0.88 to 8.94) times greater in the loss-of-only-child group, compared with the non-FP group. The associations between FP groups and MDD appeared to be stronger in the elderly population, in those who were married, less educated and those with a higher household income. The association was found progressively stronger in those who lost their only child.

CONCLUSIONS

People in the FP group, especially those who lost their only child, are more susceptible to MDD than their counterparts in the non-FP group. Mental health programmes should give special care to those who lost their only child and take existing social policies and norms, such as FP policies, into consideration.

The association between parity, CVD mortality and CVD risk factors among Norwegian women and men

BACKGROUND

Several studies have shown that women and men with two children have lower mortality than the childless, but there is less certainty about mortality, including CVD mortality, at higher parities and meagre knowledge about factors underlying the parity-mortality relationship.

METHODS

The association between parity and CVD mortality was analyzed by estimating discrete-time hazard models for women and men aged 40-80 in 1975-2015. Register data covering the entire Norwegian population were used, and the models included a larger number of relevant sociodemographic control variables than in many previous studies. To analyze the relationship between parity and seven CVD risk factors, logistic models including the same variables as the mortality models were estimated from the CONOR collection of health surveys, linked to the register data.

RESULTS

Men (but not women) who had four or more children had higher mortality from CVD than those with two, although this excess mortality was not observed for the heart disease sub-group. Overweight, possibly in part a result of less physical activity, seems to play a role in this. All CVD risk factors except smoking and alcohol may contribute to the relatively high CVD mortality among childless.

CONCLUSIONS

Childbearing is related to a number of well-known CVD risk factors, and becoming a parent or having an additional child is, on the whole, associated with lower-or at least not higher-CVD mortality in Norway. However, for men family sizes beyond three children are associated with increased CVD mortality, with risks of overweight one possible pathway.

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.

Urbanization and health: The effects of the built environment on chronic disease risk factors among women in Tanzania

Sub-Saharan Africa is experiencing rapid urban growth. Cities enable greater access to health services and improved water and sanitation infrastructure, leading to some improvements in health. However, urban settings may also be associated with more sedentary, stressful lifestyles and consumption of less nutritious food. C-reactive protein (CRP) is a measure of chronic inflammation predictive of cardiovascular disease, and high body mass index (BMI), a ratio of weight to height, indicates overweight or obesity and is associated with an increased risk of many chronic diseases. To explore the association between urbanicity and these two markers, we overlaid data from the 2010 Tanzania Demographic and Health Survey (DHS) with a satellite-derived measure of built environment. Linear regression models were constructed for the outcomes of BMI and CRP, by 1) administratively defined urban/rural categorization from the DHS, 2) satellite derived built environment, and 3) built environment stratified by urban/rural. A total of 2,212 women were included; 23% had elevated CRP, 21% were overweight or obese. A third (33%) lived in a highly built up area and 29% lived in an area classified as urban. A strong positive association between both CRP and BMI and built environment was detected; log CRP increased 0.43 in the highest built up areas compared to not built up (p<0.05); log BMI increased 0.02 in the most built up areas compared to not built up (p<0.05). However, comparing urban to rural category was only significant in unadjusted models. Models stratified by urban/rural category highlight that the variation in CRP and BMI by built environment is mainly driven by rural areas; within urban areas there is less variation. Our findings highlight the potential negative effects of urbanicity on chronic disease markers, with potentially more change detected for those transitioning from rural to urban lifestyles. Satellite-derived urbanicity measures are reproducible and provide more nuanced understanding of effects of built environment on health.

Parity is associated with cognitive function and brain age in both females and males

Previous studies of the association between parity and long-term cognitive changes have primarily focused on women and have shown conflicting results. We investigated this association by analyzing data collected on 303,196 subjects from the UK Biobank. We found that in both females and males, having offspring was associated with a faster response time and fewer mistakes made in the visual memory task. Subjects with two or three children had the largest differences relative to those who were childless, with greater effects observed in men. We further analyzed the association between parity and relative brain age (n = 13,584), a brain image-based biomarker indicating how old one's brain structure appears relative to peers. We found that in both sexes, subjects with two or three offspring had significantly reduced brain age compared to those without offspring, corroborating our cognitive function results. Our findings suggest that lifestyle factors accompanying having offspring, rather than the physical process of pregnancy experienced only by females, contribute to these associations and underscore the importance of studying such factors, particularly in the context of sex.

Maternal reproductive history and premenopausal risk of hypertension and cardiovascular disease: a Danish cohort study

OBJECTIVES

The metabolic changes of pregnancy resemble a cardiovascular risk profile and may persist postpartum, with body mass index (BMI) as a potential modifier. We examined the association between the number of live-birth pregnancies and maternal premenopausal risks of hypertension and cardiovascular disease (CVD), accounting for pre-pregnancy BMI as well as abortions and stillbirths.

DESIGN

A prospective cohort study.

SETTING

Mothers from the Danish National Birth Cohort (1996 to 2002). For each of these women, registry data on all pregnancies from 1973 to 2011 were obtained, as were self-reported pre-pregnancy weight and height.

PARTICIPANTS

A total of 44 552 first-time mothers in the Danish National Birth Cohort.

OUTCOME MEASURES

Risks of hypertension and CVD during and between live-birth pregnancies separately and combined as live-birth cycles.

RESULTS

After adjustment for abortions, stillbirths, pre-pregnancy BMI and other covariates, a higher risk of hypertension was observed in the first (HR 1.53, 95% CI: 1.37 to 1.72) and fourth and subsequent live-birth cycles (HR 1.72, 95% CI: 1.15 to 2.58), compared with the second. However, as number of live-birth pregnancies increased, risk of hypertension decreased during live-birth pregnancies and increased between live-birth pregnancies (tests for trend, p<0.01). For CVD, we found an overall J-shaped but non-significant association with number of live-birth pregnancies. No interaction with pre-pregnancy BMI (<25 versus ≥25 kg/m²) was observed.

CONCLUSIONS

Premenopausal women had the highest risk of hypertension and CVD during their first live-birth pregnancy and after their fourth live-birth pregnancy. All risks were independent of BMI before the first live-birth pregnancy and of number of abortions and stillbirths.

Number of parity is associated with low-grade albuminuria in middle-aged and elderly Chinese women

Background

Women with a higher number of pregnancies have a higher risk of developing cardiovascular diseases. Subtle fluctuations in albumin excretion could be related to pathophysiologic changes in the vascular system. We aimed to investigate the possible association of parity with low-grade albuminuria.

Methods

We conducted a community-based study in 6495 women aged 40 years or older. Low-grade albuminuria was defined according to the highest quartile of urine albumin-to-creatinine ratio in participants free of micro- or macro-albuminuria.

Results

Parous women with a higher number of pregnancies had increased age, body mass index (BMI), waist circumference (WC), systolic blood pressure (SBP), fasting plasma glucose (FPG), and fasting insulin, as well as decreased high-density lipoprotein cholesterol (HDL-C), estimated glomerular filtration rate (eGFR) levels, and proportion of menopause. The prevalence of low-grade albuminuria in parous women gradually increased with parity number. Compared with women with one childbirth, those with more than two childbirths were independently associated with a higher prevalent low-grade albuminuria (odds ratios [ORs] 1.41, 95% confidence interval [CI], 1.09–1.81) after multiple adjustments. In subgroup analysis after multiple adjustments, significant relation between parity number and prevalent low-grade albuminuria was detected in subjects age 55 years or older.

Conclusion

Number of parity is associated with prevalent low-grade albuminuria in middle-aged and elderly Chinese women without micro- or macro-albuminuria.

Mortality of midlife women with surgically verified endometriosis—a cohort study including 2.5 million person-years of observation

STUDY QUESTION

Is all-cause and cause-specific mortality increased among women with surgically verified endometriosis?

SUMMARY ANSWER

The all-cause and cause-specific mortality in midlife was lower throughout the follow-up among women with surgically verified endometriosis compared to the reference cohort.

WHAT IS KNOWN ALREADY

Endometriosis has been associated with an increased risk of comorbidities such as certain cancers and cardiovascular diseases. These diseases are also common causes of death; however, little is known about the mortality of women with endometriosis.

STUDY DESIGN, SIZE, DURATION

A nationwide retrospective cohort study of women with surgically verified diagnosis of endometriosis was compared to the reference cohort in Finland (1987–2012). Follow-up ended at death or 31 December 2014. During the median follow-up of 17 years, 2.5 million person-years accumulated.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Forty-nine thousand nine hundred and fifty-six women with at least one record of surgically verified diagnosis of endometriosis in the Finnish Hospital Discharge Register between 1987 and 2012 were compared to a reference cohort of 98 824 age- and municipality-matched women. The age (mean ± standard deviation) of the endometriosis cohort was 36.4 ± 9.0 and 53.6 ± 12.1 years at the beginning and at the end of the follow-up, respectively. By using the Poisson regression models the crude and adjusted all-cause and cause-specific mortality rate ratios (MRR) and 95% confidence intervals (CI) were assessed. Calendar time, age, time since the start of follow-up, educational level, and parity adjusted were considered in the multivariate analyses.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 1656 and 4291 deaths occurred in the endometriosis and reference cohorts, respectively. A lower all-cause mortality was observed for the endometriosis cohort (adjusted MRR, 0.73 [95% CI 0.69 to 0.77])—there were four deaths less per 1000 women over 10 years. A lower cause-specific mortality contributed to this: the adjusted MRR was 0.88 (95% CI 0.81 to 0.96) for any cancer and 0.55 (95% CI 0.47 to 0.65) for cardiovascular diseases, including 0.52 (95% CI 0.42 to 0.64) for ischemic heart disease and 0.60 (95% CI 0.47 to 0.76) for cerebrovascular disease. Mortality due to alcohol, accidents and violence, respiratory, and digestive disease-related causes was also decreased.

LIMITATIONS, REASONS FOR CAUSATION

These results are limited to women with endometriosis diagnosed by surgery. In addition, the study does not extend into the oldest age groups. The results might be explained by the characteristics and factors related to women’s lifestyle, and/or increased medical attention and care received, rather than the disease itself.

WIDER IMPLICATIONS OF THE FINDINGS

These reassuring data are valuable to women with endometriosis and to their health care providers. Nonetheless, more studies are needed to address the causality.

STUDY FUNDING/COMPETING INTEREST

This research was funded by the Hospital District of Helsinki and Uusimaa and The Finnish Medical Foundation. None of the authors report any competing interest in relation to the present work; all the authors have completed the disclosure form.

The Association Between Parity and Subsequent Cardiovascular Disease in Women: The Atherosclerosis Risk in Communities Study

Background: Previous studies are inconclusive on the relationship between parity and cardiovascular disease (CVD), with few evaluating multiple cardiovascular outcomes. It is also unclear if any relationship between parity and CVD is independent of breastfeeding. We examined the associations between parity and cardiovascular outcomes, including breastfeeding adjustment. Materials and Methods: Data were from 8,583 White and African American women, 45-64 years of age, in the Atherosclerosis Risk in Communities Study. Coronary heart disease (CHD), myocardial infarction (MI), heart failure, and strokes were ascertained from 1987 to 2016 by annual interviews and hospital surveillance. Parity and breastfeeding were self-reported. Cox proportional hazards regression estimated hazard ratios (HR) for the association between parity and cardiovascular outcomes, adjusting for baseline sociodemographic, clinical and lifestyle factors, and breastfeeding. Results: Women reported no pregnancies (6.0%), or having 0 (1.6%), 1-2 (36.2%), 3-4 (36.4%), or 5+ (19.7%) live births. During 30 years follow-up, there were 1,352 CHDs, 843 MIs, 750 strokes, and 1,618 heart failure events. Compared with women with 1-2 prior births, those with prior pregnancies and no live births had greater incident CHD (HR = 1.64, 95% confidence interval 1.14-2.42) and heart failure risk (1.46, 1.04-2.05), after adjustment for baseline characteristics. Women with 5+ births had greater risk of CHD (1.29, 1.10-1.52) and hospitalized MI (1.38, 1.13-1.69), after adjustment for baseline characteristics and breastfeeding. Conclusions: In a diverse U.S. cohort, a history of 5+ live births is associated with CHD risk, specifically, MI, independent of breastfeeding. Having a prior pregnancy and no live birth is associated with greater CHD and heart failure risk.

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.

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.

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.