Parity and coronary heart disease among women in the American Cancer Society CPS II population

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.

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.

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.

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.

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.

Association between parity and persistent weight gain at age 40-60 years: a longitudinal prospective cohort study

OBJECTIVES

Physiological metabolic adaptations occur in the pregnant woman. These may persist postpartum and thereby contribute to an unfavourable cardiovascular disease (CVD) risk profile in parous women. The aim of the current study is to assess time-dependent changes of cardiometabolic health in parous women compared with nulliparous women.

DESIGN AND SETTING

We studied data of 2459 women who participated in the Prevention of Renal and Vascular End-stage Disease study, a population-based prospective longitudinal cohort for assessment of CVD and renal disease in the general population.

PARTICIPANTS

We selected women ≥40 years at the first visit, who reported no new pregnancies during the four follow-up visits. All women were categorised in parity groups, and stratified for age.

OUTCOME MEASURES

We compared body mass index (BMI), high-density lipoprotein (HDL) cholesterol, blood pressure as continuous measurements and as clinical relevant CVD risk factors among parity groups over the course of 6 years using generalised estimating equation models adjusted for age.

RESULTS

The BMI was significantly higher in women para 2 or more in all age categories: per child, the BMI was 0.6 kg/m² higher. corresponding with 1.5-2.0 kg weight gain per child. HDL cholesterol was significantly lower in women para 2 or more aged 40-49 and 50-59 years: per child, the HDL cholesterol was up to 0.09 mmol/L lower. Blood pressure did not differ among parity groups in any of the age categories.

CONCLUSIONS

Higher parity is associated with higher BMI, lower HDL cholesterol and a higher prevalence of cardiovascular risk factors, which is constant over time. These findings warrant for prospective research assessing determinants of cardiometabolic health at earlier age to understand the role of pregnancy in the development of CVD in women.

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.

Association between number of children and carotid intima-media thickness in Bangladesh

Previous studies on the association between number of children and carotid intima-media thickness (cIMT) were limited to Western populations. Pregnancy in women is associated with physiologic changes that may influence the risk of cardiovascular disease. Comparing the association between number of children and cIMT in men and women can provide insights on whether the association may be due to pregnancy. We investigated the association between number of children and cIMT among 718 female (mean age 37.5 years) and 417 male participants (mean age 41.3 years), randomly selected from the Health Effect of Arsenic Longitudinal Study (HEALS), a population-based cohort study in Bangladesh. Multivariate linear regression was used to assess the association and to control for education attainment, history of diabetes, age, smoking, betel use, BMI, systolic blood pressure, and diastolic blood pressure. The average number of children was 4.43 for women and 3.74 for men. There were no nulliparous women. We observed a positive association between number of children and cIMT in women. Mean cIMT increased by 4.5 μm (95% CI, 0.8–8.1) per increment of one birth (P = 0.02). Compared to women with two children, cIMT in women with 4 children and ≥5 children was 23.6μm (95%CI, 2.6–44.7; P = 0.03) and 25.1 μm (95%CI, 3.5–46.6; P = 0.02) greater, respectively. The association was not modified by BMI, SBP, betel use or age. Data in men showed no evidence of association (P = 0.4). The finding suggests a role of high parity in atherosclerosis in women of a low-income, high parity population.

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.

"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.

Adolescent Childbirth Is Associated With Greater Framingham Risk Scores for Cardiovascular Disease Among Participants of the IMIAS (International Mobility in Aging Study)

BACKGROUND

Previous studies observe associations between lifetime parity and cardiovascular disease, but relatively fewer investigate age at first childbirth (AFB). Herein, we examine the association of AFB with a summary cardiovascular risk measure (Framingham Risk Score [FRS]).

METHODS AND RESULTS

As part of the IMIAS (International Mobility in Aging Study), data were collected in 2012 among 1047 women, aged 65 to 74 years, from Canada, Albania, Colombia, and Brazil. FRSs were calculated to describe cardiovascular risk profiles, and linear regression analyses were performed, adjusting for early life and socioeconomic variables. Women with an AFB of <20 years were compared with women with an AFB of 20 to 24, 25 to 29, and ≥30 years, as well as nulliparous women. We also compared FRS between combinations of AFB and parity categories: nulliparous women, parity 1 to 3 combined with AFB <20 years, parity ≥4 with AFB <20 years, parity 1 to 3 with AFB ≥20 years, and parity ≥4 with AFB ≥20 years. Women with an AFB of <20 years had a higher mean FRS compared with all other AFB groups. Compared with the lowest AFB risk group (25-29 years), women with an AFB of <20 years had a 5.8-point higher mean FRS (95% confidence interval, 3.4-8.3 points). Nulliparous women presented the lowest mean FRS in all analyses. The analysis comparing combinations of AFB and parity categories showed no meaningful differences in FRS between women who had 1 to 3 childbirths and those who had ≥4 childbirths within the stratum of AFB <20 years, and in the stratum of AFB ≥20 years.

CONCLUSIONS

Our analyses suggest that nulliparity and AFB, rather than increasing parity, drive the association with cardiovascular disease risk.

Reproductive Factors and Incidence of Heart Failure Hospitalization in the Women's Health Initiative

BACKGROUND

Reproductive factors reflective of endogenous sex hormone exposure might have an effect on cardiac remodeling and the development of heart failure (HF).

OBJECTIVES

This study examined the association between key reproductive factors and the incidence of HF.

METHODS

Women from a cohort of the Women's Health Initiative were systematically evaluated for the incidence of HF hospitalization from study enrollment through 2014. Reproductive factors (number of live births, age at first pregnancy, and total reproductive duration [time from menarche to menopause]) were self-reported at study baseline in 1993 to 1998. We employed Cox proportional hazards regression analysis in age- and multivariable-adjusted models.

RESULTS

Among 28,516 women, with an average age of 62.7 ± 7.1 years at baseline, 1,494 (5.2%) had an adjudicated incident HF hospitalization during an average follow-up of 13.1 years. After adjusting for covariates, total reproductive duration in years was inversely associated with incident HF: hazard ratios (HRs) of 0.99 per year (95% confidence interval [CI]: 0.98 to 0.99 per year) and 0.95 per 5 years (95% CI: 0.91 to 0.99 per 5 years). Conversely, early age at first pregnancy and nulliparity were significantly associated with incident HF in age-adjusted models, but not after multivariable adjustment. Notably, nulliparity was associated with incident HF with preserved ejection fraction in the fully adjusted model (HR: 2.75; 95% CI: 1.16 to 6.52).

CONCLUSIONS

In post-menopausal women, shorter total reproductive duration was associated with higher risk of incident HF, and nulliparity was associated with higher risk for incident HF with preserved ejection fraction. Whether exposure to endogenous sex hormones underlies this relationship should be investigated in future studies.

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).

Parenthood and the risk of cardiovascular diseases among 0.5 million men and women: findings from the China Kadoorie Biobank

Background

Women's parity has been associated with risk of cardiovascular disease (CVD). It is unclear, however, whether it reflects biological effects of childbearing or uncontrolled socio-economic and lifestyle factors associated with childrearing. We assessed the association between number of children and incident CVD outcomes separately in women and men.

Methods

In 2004-08, the nationwide China Kadoorie Biobank recruited 0.5 million individuals aged 30-79 years from 10 diverse regions. During 7 years of follow-up, 24 432 incident cases of coronary heart disease (CHD) and 35 736 of stroke were recorded among 489 762 individuals without prior CVD. Multivariable Cox regression models were used to estimate sex-specific hazard ratios (HRs) and 95% confidence intervals (CIs) for CHD and stroke associated with number of children.

Results

Overall, 98% of all participants had children and the mean number of children declined progressively from four in older participants to one or two in younger participants. Compared with childless women, women with children had an increased risk of CHD, but not of stroke [HR (95% CI): 1.14 (1.00; 1.30) and 1.03 (0.92; 1.16)]. Corresponding results for men were 1.20 (1.06; 1.35) and 1.13 (1.03; 1.24), respectively. In individuals with children, there was a log-linear association between number of children and CVD outcomes; in women, each additional child was associated with adjusted HRs of 1.02 (1.01; 1.04) for CHD and 1.02 (1.01; 1.03) for stroke, similar in magnitude to that in men [1.03 (1.01; 1.04) for CHD and 1.02 (1.01; 1.03) for stroke].

Conclusion

In Chinese adults, the association between the number of children and risk of CHD and stroke was similar between men and women, suggesting that factors associated with parenthood and childrearing are more likely to affect the risk of CVD outcomes than factors associated with childbearing.

Parity, weight change, and maternal risk of cardiovascular events

BACKGROUND

High parity has been suggested to increase risk of maternal cardiovascular disease independent of body mass index measured after childbearing. Pregnancy is, however, associated with persistent weight gain and metabolic changes that, independent of parity, increase the risk of cardiovascular disease. It could therefore be questioned if high parity independently increases the risk of cardiovascular disease or if this association may be confounded, mediated, or modified by other parity-related factors.

OBJECTIVE

We sought to investigate the association between parity and risk of cardiovascular disease, and secondary outcomes in terms of myocardial infarction and cerebral infarction, with particular focus on potential mediation by anthropometric measures and effect modification by lactation.

STUDY DESIGN

We used data from 16,515 female participants (age 44.5-73.6 years) of the population-based Malmö Diet and Cancer Study with baseline examination from 1991 through 1996. The Malmö Diet and Cancer Study was followed up throughout 2010, with a median follow-up of 15.8 years. We used Cox proportional hazards model to examine the association between parity and cardiovascular disease.

RESULTS

Adjusted for age and other potential confounders, grand multiparous women (≥5 children) had an increased risk of cardiovascular disease (hazard ratio, 1.60; 95% confidence interval, 1.20-2.14), myocardial infarction (hazard ratio, 1.68; 95% confidence interval, 1.15-2.45), and cerebral infarction (hazard ratio, 1.74; 95% confidence interval, 1.18-2.58) compared to women with 2 children. Additional adjustment for baseline body mass index and weight change since age 20 years attenuated the risk, but the increased risk for cardiovascular disease (hazard ratio, 1.38; 95% confidence interval, 1.02-1.87) and myocardial infarction (hazard ratio, 1.53; 95% confidence interval, 1.04-2.26) in grand multiparous women remained significant. Models stratified by lactation time showed that risk was only raised in grand multiparous women who had a mean lactation time of <4 mo/child. In sensitivity analyses excluding women with a history of diabetes at baseline, risk estimates for grand multiparous women became nonsignificant in the full model.

CONCLUSION

Part of the increased risk of cardiovascular disease and myocardial infarction in grand multiparous women seems to be mediated by weight gain and potentially by higher likelihood of type 2 diabetes mellitus. Lactation may modify the increased risk of grand multiparity in that longer duration might offset the cardiovascular disease risk.

Parity, breastfeeding and risk of coronary heart disease: A pan-European case-cohort study

OBJECTIVE

There is uncertainty about the direction and magnitude of the associations between parity, breastfeeding and the risk of coronary heart disease (CHD). We examined the separate and combined associations of parity and breastfeeding practices with the incidence of CHD later in life among women in a large, pan-European cohort study.

METHODS

Data were used from European Prospective Investigation into Cancer and Nutrition (EPIC)-CVD, a case-cohort study nested within the EPIC prospective study of 520,000 participants from 10 countries. Information on reproductive history was available for 14,917 women, including 5138 incident cases of CHD. Using Prentice-weighted Cox regression separately for each country followed by a random-effects meta-analysis, we calculated hazard ratios (HRs) and 95% confidence intervals (CIs) for CHD, after adjustment for age, study centre and several socioeconomic and biological risk factors.

RESULTS

Compared with nulliparous women, the adjusted HR was 1.19 (95% CI: 1.01-1.41) among parous women; HRs were higher among women with more children (e.g., adjusted HR: 1.95 (95% CI: 1.19-3.20) for women with five or more children). Compared with women who did not breastfeed, the adjusted HR was 0.71 (95% CI: 0.52-0.98) among women who breastfed. For childbearing women who never breastfed, the adjusted HR was 1.58 (95% CI: 1.09-2.30) compared with nulliparous women, whereas for childbearing women who breastfed, the adjusted HR was 1.19 (95% CI: 0.99-1.43).

CONCLUSION

Having more children was associated with a higher risk of CHD later in life, whereas breastfeeding was associated with a lower CHD risk. Women who both had children and breastfed did have a non-significantly higher risk of CHD.

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

Pregnancy leads to physiological changes in lipid, glucose levels, and weight, which may increase the risk of coronary heart disease (CHD) in later life. The purpose of this study was to examine whether parity is associated with CHD in middle-aged and older Chinese women. A total of 20,207 women aged 37 to 94 years from Dongfeng-Tongji Cohort who completed the questionnaire, were medically examined and provided blood samples, were included in our analysis. CHD cases were determined by self-report of physician diagnosis through face-to-face interviews. Logistic regression models were used to estimate the association between parity and CHD. The rate of CHD was 15.8%. Parity had a positive association with CHD without adjustment of covariates. After controlling for the potential confounders, increasing risk of coronary heart disease was observed in women who had two (OR, 1.65; 95% CI, 1.41-1.93), three (OR, 1.76; 95% CI, 1.44-2.16), and four or more live births (OR, 1.71; 95% CI, 1.33-2.20) compared with women with just one live birth. High parity was significantly associated with increasing risk of CHD in Chinese women. This suggests that multiparity may be a risk factor for CHD among Chinese women.

Reproductive factors and risk of mortality in the European Prospective Investigation into Cancer and Nutrition; a cohort study

BACKGROUND

Reproductive events are associated with important physiologic changes, yet little is known about how reproductive factors influence long-term health in women. Our objective was to assess the relation of reproductive characteristics with all-cause and cause-specific mortality risk.

METHODS

The analysis was performed within the European Investigation into Cancer and Nutrition prospective cohort study, which enrolled >500,000 women and men from 1992 to 2000, who were residing in a given town/geographic area in 10 European countries. The current analysis included 322,972 eligible women aged 25-70 years with 99 % complete follow-up for vital status. We assessed reproductive characteristics reported at the study baseline including parity, age at the first birth, breastfeeding, infertility, oral contraceptive use, age at menarche and menopause, total ovulatory years, and history of oophorectomy/hysterectomy. Hazard ratios (HRs) and 95 % confidence intervals (CIs) for mortality were determined using Cox proportional hazards regression models adjusted for menopausal status, body mass index, physical activity, education level, and smoking status/intensity and duration.

RESULTS

During a mean follow-up of 12.9 years, 14,383 deaths occurred. The HR (95 % CI) for risk of all-cause mortality was lower in parous versus nulliparous women (0.80; 0.76-0.84), in women who had ever versus never breastfed (0.92; 0.87-0.97), in ever versus never users of oral contraceptives (among non-smokers; 0.90; 0.86-0.95), and in women reporting a later age at menarche (≥15 years versus <12; 0.90; 0.85-0.96; P for trend = 0.038).

CONCLUSIONS

Childbirth, breastfeeding, oral contraceptive use, and a later age at menarche were associated with better health outcomes. These findings may contribute to the development of improved strategies to promote better long-term health in women.

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.

Is interpregnancy interval associated with cardiovascular risk factors in later life? A cohort study

OBJECTIVES

Pregnancy represents a metabolic challenge to women; in a normal pregnancy, transient metabolic changes occur that support the needs of the growing fetus. It is possible that repeating this challenge within a relatively short amount of time may result in lasting damage to the woman's cardiovascular health. Conversely, it is also possible that a long interpregnancy interval (IPI) may reflect subfertility, which has been found to be associated with cardiovascular disease (CVD). We examine the associations of short and long IPI with measures of cardiovascular health.

DESIGN

Prospective cohort.

SETTING

Mothers of the Avon Longitudinal Study of Parents and Children (ALSPAC).

PARTICIPANTS

Women with two live births in order to control for confounding by parity.

OUTCOME MEASURES

Arterial distensibility, common carotid intima, adiposity, blood pressure, lipids, glucose, insulin, proinsulin, triglycerides, C reactive protein.

RESULTS

25% (n=3451) of ALSPAC mothers had provided sufficient data to determine full reproductive history-of these, 1477 had two live births, with 54% mothers having non-missing data on all variables required for our analyses. A total of 1268 mothers with IPI (interbirth interval minus 9 months' gestation) had CVD risk factors measured/imputed at mean age 48 years. After adjusting for confounding, we found no association of either short (≤15 months) or long (>27 months) IPI and increased levels of cardiovascular risk factors. There was some suggestion that women with long and short IPIs had a more favourable lipid profile compared with women whose IPI was 16-27 months; however, the differences were small in magnitude and imprecisely estimated.

CONCLUSIONS

This study does not support the hypothesis that either long or short IPI is a risk factor for later cardiovascular health.

A prospective population-based cohort study of lactation and cardiovascular disease mortality: the HUNT study

Background

Recent studies suggest that lactation has long-term effects on risk for cardiovascular disease in women, but the effects on cardiovascular mortality are less well known.

Method

In a Norwegian population-based prospective cohort study, we studied the association of lifetime duration of lactation with cardiovascular mortality in 21,889 women aged 30 to 85 years who attended the second Nord-Trøndelag Health Survey (HUNT2) in 1995–1997. The cohort was followed for mortality through 2010 by a linkage with the Cause of Death Registry. Adjusted hazard ratios (HR) for death from all causes and cardiovascular disease were calculated using Cox regression.

Results

During follow-up, 1,246 women died from cardiovascular disease. Parous women younger than 65 years who had never lactated had a higher cardiovascular mortality than the reference group of women who had lactated 24 months or more (HR 2.77, 95% confidence interval [CI]: 1.28, 5.99). There was some evidence of a U-shaped association, where women who reported lactating 7–12 months had a HR of 0.55 (95% CI: 0.27, 1.09). No clear associations were observed among women 65 years or older.

Conclusions

Excess cardiovascular mortality rates were observed among parous women younger than 65 years who had never lactated. These findings support the hypothesis that lactation may have long-term influences on maternal cardiovascular health.

Pregnancy characteristics and women's future cardiovascular health: an underused opportunity to improve women's health?

Growing evidence indicates that women with a history of common pregnancy complications, including fetal growth restriction and preterm delivery (often combined as low birth weight), hypertensive disorders of pregnancy, and gestational diabetes, are at increased risk for cardiovascular disease later in life. The purpose of this paper was to review the associations of parity and these 4 pregnancy complications with cardiovascular morbidity and mortality; to review the role of cardiovascular risk factors before, during, and after pregnancy complications in explaining these associations; and to explore the implications of this emerging science for new research and policy. We systematically searched for relevant cohort and case-control studies in Medline through December 2012 and used citation searches for already published reviews to identify new studies. The findings of this review suggest consistent and often strong associations of pregnancy complications with latent and future cardiovascular disease. Many pregnancy complications appear to be preceded by subclinical vascular and metabolic dysfunction, suggesting that the complications may be useful markers of latent high-risk cardiovascular trajectories. With further replication research, these findings would support the utility of these prevalent pregnancy complications in identifying high-risk women for screening, prevention, and treatment of cardiovascular disease, the leading cause of morbidity and mortality among women.

Metabolic and cardiovascular outcomes of fatherhood: results from a cohort of study in subjects with sexual dysfunction

INTRODUCTION

Previous cross-sectional and longitudinal studies reported a negative correlation between fatherhood and testosterone (T) levels, likely due to a centrally mediated downregulation of the hypothalamic-pituitary-gonadal axis. Moreover, epidemiological data indicate that fatherhood might affect metabolic and cardiovascular outcomes, although different results have been reported. Up to now, no studies have evaluated these associations in a population of men seeking treatment for sexual dysfunction (SD).

AIM

To explore biological and clinical correlates of number of children (NoC) and its possible associations with forthcoming major cardiovascular events (MACE) in a sample of men with SD.

METHODS

A consecutive series of 4,045 subjects (mean age 52 ± 13.1 years old) attending the Outpatient Clinic for SD was retrospectively studied. A subset of the previous sample (N = 1,687) was enrolled in a longitudinal study.

MAIN OUTCOME MEASURES

Information on MACE was obtained through the City of Florence Registry Office.

RESULTS

Among patients studied, 31.6% had no children, while 26.3% reported having one child, 33.4% two, and 8.8% three or more children. Although fatherhood was negatively related with follicle-stimulating hormone levels and positively with testis volume, we found a NoC-dependent, stepwise decrease in T plasma levels, not compensated by a concomitant increase in luteinizing hormone. NoC was associated with a worse metabolic and cardiovascular profile, as well as worse penile blood flows and a higher prevalence of metabolic syndrome (MetS). In the longitudinal study, after adjusting for confounders, NoC was independently associated with a higher incidence of MACE. However, when the presence of MetS was introduced as a further covariate, the association was no longer significant.

CONCLUSIONS

This study supports the hypothesis that bond maintenance contexts and fatherhood are associated with an adaptive downregulation of the gonadotropin-gonadal axis, even in a sample of men with SD. Moreover, our data suggest that NoC predicts MACE, most likely because of an unfavorable, lifestyle-dependent, parenthood-associated behavior.

Association of number of live births with left ventricular structure and function. The Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

Pregnancy is associated with marked maternal cardiovascular/hemodynamic changes. A greater number of pregnancies may be associated with long-term subclinical changes in left ventricular (LV) remodeling.

METHODS

Among 2,234 white, black, Hispanic, and Chinese women (mean age 62 years) in the MESA, we used linear regression to relate live births and cardiac magnetic resonance imaging LV measures. Covariates included age, ethnicity, height, income, education, birth country, smoking, menopause, and oral contraceptive duration. Models were additionally adjusted for potential mediators: systolic blood pressure, antihypertensive use, total/high-density lipoprotein cholesterol, triglycerides, diabetes, and body mass index. We performed sensitivity analyses excluding 763 women in the lowest socioeconomic group: annual income <$25,000 and lower high school level of education.

RESULTS

With each live birth, LV mass increased 1.26 g; LV end-diastolic volume, 0.74 mL; and LV end-systolic volume, 0.45 mL; LV ejection fraction decreased 0.18% (P trend <0.05). Changes were most notable for the category of women with ≥5 pregnancies. Upon adjustment for potential biologic mediators, live births remained positively associated with LV mass and end-systolic volume. Live births remained significantly associated with LV end-systolic, end-diastolic volumes, and LV mass (P trend ≤0.02) after excluding women in the lowest socioeconomic group.

CONCLUSIONS

Number of live births is associated with key LV structural and functional measures in middle to older ages, even after adjustment for sociodemographic factors and cardiovascular disease risk factors. Hemodynamic changes during pregnancy may be associated with cardiac structure/function beyond childbearing years.

The association of reproductive history with all-cause and cardiovascular mortality in older women: the Rancho Bernardo Study

OBJECTIVE

To examine associations of gravidity and parity with all-cause, cardiovascular disease (CVD), and coronary heart disease (CHD) mortality in postmenopausal women.

DESIGN

Prospective cohort study.

SETTING

Rancho Bernardo, a southern California community.

PATIENT(S)

One thousand two hundred ninety-four postmenopausal women ages 50-96 who attended a 1984-87 research clinic visit at which reproductive and medical histories were obtained and who were followed through 2007.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

All-cause, CVD, CHD, and non-CHD CVD mortality, determined by nosologist-coded death certificates.

RESULT(S)

Average baseline age was 70.6 ± 9.2. Numbers of pregnancies ranged from 0 to 13 (median = 2); births ranged from 0 to 11 (median = 2). During a median of 19.3 years of follow-up, 707 women (54.6%) died, with 46.5% attributed to CVD, 20.5% to CHD, and 26.0% to non-CHD CVD. Trend analyses showed inverse associations of gravidity with CVD mortality and non-CHD CVD mortality. Women with four or more pregnancies were less likely than nulligravidas to have fatal CVD (hazard ratio [HR] = 0.63, 95% confidence interval [CI] = 0.40-0.99) and non-CHD CVD (HR = 0.48, 95% CI = 0.26-0.91) independent of age, years postmenopause, obesity, and HDL. Associations increased after the first decade of follow-up. Parity and gravidity were not associated with overall or CHD mortality.

CONCLUSION(S)

High gravidity was associated with reduced CVD and non-CHD CVD mortality in postmenopausal women. Protective associations could reflect biological mechanisms that occur with repeated pregnancy or greater social support related to family size among multiparous women.

Reproductive history and mortality from cardiovascular disease among women textile workers in Shanghai, China

BACKGROUND

Few studies have examined the possible effects of reproductive factors on cardiovascular disease (CVD) risks in Asian women.

METHODS

A cohort of 267,400 female textile workers in Shanghai, China, was administered a questionnaire at enrolment (1989-91) and followed for mortality through 2000. Relative risks (hazard ratios) for ischaemic heart disease (IHD), ischaemic stroke and haemorrhagic stroke were calculated using Cox proportional hazards modelling, adjusting for relevant co-variates.

RESULTS

Risks were not consistently associated with age at menopause, parity, stillbirths, miscarriages or duration of lactation. An increasing trend in IHD mortality risk, but not stroke, was observed with decreasing age at menarche. There was no evidence of increased CVD mortality risk by oral or injectable contraceptive use or induced abortions. As expected, greater mortality rates from CVD and increased CVD risks were also observed with smoking.

CONCLUSIONS

Use of steroid contraceptives, induced abortions and reduced parity from China's one-child-per-family policy has not had an adverse effect on risk of CVD mortality in this cohort.

Parity and total, ischemic heart disease and stroke mortality. The Adventist Health Study, 1976-1988

In a prospective study with information about life style and reproductive factors, we assessed the relationship between parity and total, ischemic heart disease, and stroke mortality. The large majority of the 19,688 California Seventh-day Adventist women included did not smoke or drink alcohol, 31 percent never ate meat and physical activity was relatively high. Cox proportional hazard analysis was conducted with parity as the main independent variable and with adjustment for a number of other possible confounders. During follow-up from 1976 through 1988, there were 3,122 deaths; 782 deaths from ischemic heart disease and 367 deaths due to stroke. There were no relationships between parity and total mortality (P-value for overall effect of parity = 0.32). Grand multiparous women (>4 children) had somewhat increased ischemic heart disease mortality (MRR = 1.45, 95% CI: 1.15, 1.84) before adjustment for educational level. After adjustment for educational level and marital status, there were no relationship with mortality from ischemic heart disease (P = 0.29) or stroke (P = 0.72). In parous women, there were, after adjustment for age at first delivery, some suggestions of an increased total mortality in women with one child. For ischemic heart disease and stroke mortality, no associations were found. Stratified and adjusted analyses confirmed these results. Thus, we found no consistent relationships between parity and total, ischemic heart disease or stroke mortality. However, a longer follow-up would have been helpful and the conclusions may be somewhat influenced by the lifestyle of the women included.

Miscarriage and risk of cardiovascular disease

In a nationally representative sample (the Health 2000 Survey) comprising 3,937 Finnish women aged 30-99 years, we examined the association of miscarriage (assessed by questionnaire) with risk of cardiovascular disease (assessed by physician's examination and linkages to hospital discharge and drug reimbursement registers). We considered age, smoking, body mass index, waist/hip ratio, physical activity, education, number of previous pregnancies, blood pressure, and fasting blood glucose and cholesterol as potentially confounding factors in the analysis. In women 50-74 years of age who had experienced pregnancy, history of miscarriage tended to be associated with a higher risk of myocardial infarction (age-adjusted odds ratio (OR): 2.1, 95% confidence interval (CI): 1.0-4.3), and the risk increased significantly with the number of miscarriages (age-adjusted OR per miscarriage: 1.4, 95% CI: 1.1-1.8). These results suggest that women who experience repeated miscarriages may be at an increased risk of cardiovascular disease later in life.

Parity and risk of later-life maternal cardiovascular disease

BACKGROUND

Prior studies relating parity with maternal cardiovascular disease (CVD) have been performed in relatively small study samples without accounting for pregnancy-related complications associated with CVD.

METHODS

We examined the associations between parity and maternal risk of later-life CVD in a population-based cohort study using data from the Swedish population registers. Women born from 1932 to 1955 were followed until the occurrence of CVD, death, emigration, or end of follow-up (December 31, 2005). Cox proportional hazards models were used to estimate associations between parity and risk of CVD accounting for birth year, yearly income, education level, country of birth, hypertension (pregestational hypertension or gestational hypertension, with or without proteinuria), diabetes (type 1, type 2, or gestational diabetes), preterm birth, small for gestational age, and stillbirth.

RESULTS

During a median follow-up time of 9.5 years (range 0-23.5), there were 65,204 CVD events in the full sample of women. Among 1,332,062 women, parity was associated with CVD in a J-shaped fashion, with 2 births representing the nadir of risk (global P value < .0001). Upon accounting for pregnancy-related complications in a subset of women with at least 1 childbirth after 1973 (n = 590,725), the association of parity with CVD was similar. Compared with women with 2 childbirths, the multivariable-adjusted hazard ratios (95% CIs) for women with 1 and >/=5 births were 1.09 (1.03-1.15) and 1.47 (1.37-1.57), respectively.

CONCLUSIONS

In conclusion, parity was associated with incident maternal CVD in a J-shaped fashion, even after accounting for socioeconomic factors and pregnancy-related complications.

Childbearing is associated with higher incidence of the metabolic syndrome among women of reproductive age controlling for measurements before pregnancy: the CARDIA study

OBJECTIVE

We sought to prospectively examine whether childbearing is associated with higher incidence of the metabolic syndrome (MetS) after delivery among women of reproductive age.

STUDY DESIGN

In 1451 nulliparas who were aged 18-30 years and free of the MetS at baseline (1985-1986) and reexamined up to 4 times during 20 years, we ascertained incident MetS defined by the National Cholesterol Education Program Adult Treatment Panel III criteria among time-dependent interim birth groups by gestational diabetes mellitus (GDM): (0 [referent], 1 non-GDM, 2+ non-GDM, 1+ GDM births). Complementary log-log models estimated relative hazards of the MetS among birth groups adjusted for race, age, and baseline and follow-up covariates.

RESULTS

We identified 259 incident MetS cases in 25,246 person-years (10.3/1000 person-years). Compared with 0 births, adjusted relative hazards (95% confidence interval [CI]) were 1.33 (95% CI, 0.93-1.90) for 1 non-GDM, 1.62 (95% CI, 1.16-2.26) for 2+ non-GDM (P trend = .02), and 2.43 (95% CI, 1.53-3.86) for 1+ GDM births.

CONCLUSION

Increasing parity is associated with future development of the MetS independent of prior obesity and pregnancy-related weight gain. Risk varies by GDM status.

Pregnancy, childrearing, and risk of stroke in Chinese women

BACKGROUND AND PURPOSE

Although it has been suggested that high gravidity and parity increase the risk for coronary heart disease, their associations with stroke are unclear.

METHODS

We evaluated associations of gravidity and parity with incidence of stroke in the Shanghai Women's Health Study (SWHS), a population-based cohort study of 74 942 Chinese women aged 40 to 70 years at enrollment (1996 to 2000). We also examined the association between number of children and stroke prevalence in both SWHS participants and their husbands. Stroke cases were ascertained through in-person interviews and linkage with vital statistics registries.

RESULTS

During a mean follow-up of 7.3 years, 2343 incident cases of stroke were identified. Women with more pregnancies or live births had a significantly increased risk for incident stroke. After adjustment for socioeconomic status and other potential confounders, women with > or =5 pregnancies had a hazard ratio for incident stroke of 1.45 (95% CI, 1.18 to 1.77) compared with those with only one pregnancy. At baseline recruitment, 859 and 1274 prevalent cases of stroke were reported among SWHS participants and their husbands, respectively. Stroke prevalence increased with increasing number of children in both women and men. Adjusted ORs of prevalent stroke for having > or =5 children versus having one child were 1.61 (95% CI, 1.16 to 2.23) in women and 1.45 (1.11 to 1.89) in men.

CONCLUSIONS

High gravidity or parity may be related to increased risk of stroke in women. Chronic stress and adverse lifestyle factors related to childrearing may contribute importantly to the increased risk.

Duration of lactation and incidence of myocardial infarction in middle to late adulthood

OBJECTIVE

We assessed the relation between duration of lactation and maternal incident myocardial infarction.

STUDY DESIGN

This was a prospective cohort study of 89,326 parous women in the Nurses' Health Study.

RESULTS

During 1,350,965 person-years of follow-up, 2540 cases of coronary heart disease were diagnosed. Compared with parous women who had never breastfed, women who had breastfed for a lifetime total of 2 years or longer had 37% lower risk of coronary heart disease (95% confidence interval, 23-49%; P for trend < .001), adjusting for age, parity, and stillbirth history. With additional adjustment for early-adult adiposity, parental history, and lifestyle factors, women who had breastfed for a lifetime total of 2 years or longer had a 23% lower risk of coronary heart disease (95% confidence interval, 6-38%; P for trend = .02) than women who had never breastfed.

CONCLUSION

In a large, prospective cohort, long duration of lactation was associated with a reduced risk of coronary heart disease.

Pregnancy-related factors and the risk of isolated systolic hypertension

BACKGROUND

Isolated systolic hypertension (ISH) is known to be a strong predictor of cerebrovascular and cardiac events, especially in women. Metabolic and hormonal changes associated with reproductive history may contribute to the development of cardiovascular diseases. The aim of this study was to identify associations between pregnancy-related factors and ISH.

METHODS

A cross-sectional study based on a random sample of 3937 Finnish women aged 30-99 was carried out. Associations between pregnancy-related factors and ISH were analyzed using multivariate analyses.

RESULTS

Of 3470 subjects, 26% had ISH. Younger age at first delivery predicted a higher risk of ISH (odds ratio after adjustment for age, education, smoking, height and weight = 1.31, 95% CI 1.07-1.61). Age at first and last delivery was significantly associated with age, education, marital status and use at any time of hormone replacement therapy (HRT); age at first delivery was also associated with toxemia in any pregnancy, weight and body mass index (BMI). In the univariate analyses, ISH was significantly associated with age, height, weight, BMI, education, marital status, oral contraceptive pills use at any time and HRT use at any time.

CONCLUSION

This population-based study showed that early age at first delivery increased the risk of ISH, which may in turn increase cerebrovascular and cardiac events after menopause. Age at first delivery is heavily dependent on education, which may be linked to the risk of developing of cardiovascular disease throughout adulthood. The other plausible mechanism may be adiposity due to pregnancy.

Lactation and changes in maternal metabolic risk factors

OBJECTIVE

To examine the relationship between duration of lactation and changes in maternal metabolic risk factors.

METHODS

This 3-year prospective study examined changes in metabolic risk factors among lactating women from preconception to postweaning and among nonlactating women from preconception to postdelivery, in comparison with nongravid women. Of 1,051 (490 black, 561 white) women who attended two consecutive study visits in years 7 (1992-1993) and 10 (1995-1996), 942 were nongravid and 109 had one interim birth. Of parous women, 48 (45%) did not lactate, and 61 (55%) lactated and weaned before year 10. The lactated and weaned women were subdivided by duration of lactation into less than 3 months and 3 months or more. Multiple linear regression models estimated mean 3-year changes in metabolic risk factors adjusted for age, race, parity, education, and behavioral covariates.

RESULTS

Both parous women who did not lactate and parous women who lactated and weaned gained more weight (+5.6, +4.4 kg) and waist girth (+5.3, +4.9 cm) than nongravid women over the 3-year interval; P<.001. Low-density lipoprotein cholesterol (+6.7 mg/dL, P<.05) and fasting insulin (+2.6 microunits, P=.06) increased more for parous women who did not lactate than for nongravid and parous women who lactated and weaned. High-density lipoprotein cholesterol decrements for both parous women who did not lactate and parous women who lactated and weaned were 4.0 mg/dL greater than for nongravid women (P<.001). Among parous, lactated and weaned women, lactation for 3 months or longer was associated with a smaller decrement in high-density lipoprotein cholesterol (-1.3 mg/dL versus -7.3 mg/dL for less than 3 months; P<.01).

CONCLUSION

Lactation may attenuate unfavorable metabolic risk factor changes that occur with pregnancy, with effects apparent after weaning. As a modifiable behavior, lactation may affect women's future risk of cardiovascular and metabolic diseases.

LEVEL OF EVIDENCE

II.

Menstrual and reproductive factors and risk of non-fatal acute myocardial infarction in Italy

OBJECTIVE

We analyzed the relation between factors related to endogenous female hormones and the risk of acute myocardial infarction (AMI).

STUDY DESIGN

We used a combined dataset from three Italian case-control studies, including 609 women with non-fatal AMI and 1106 controls hospitalized for acute conditions.

RESULTS

The odds ratios (OR) of AMI were 1.36 (95% confidence intervals, CI 0.95-1.96) in women with an irregular menstrual pattern compared to a regular one, and 1.45 (95% CI 1.07-1.97) in parae compared to nulliparae, without linear trend in risk with number of children. No relation was found with menopausal status, age at menarche and menopause, abortion, and age at first and last birth. Compared to women without abortions the OR was 0.84 (95% CI 0.60-1.18) for >1 abortion; compared to women without spontaneous or induced abortion, the ORs were 0.92 (95% CI 0.62-1.38) for >1 spontaneous and 0.63 (95% CI 0.36-1.08) for >1 induced abortion. The association of parity and irregular menstrual cycles was stronger in pre-/peri-menopausal women and in current smokers. Compared to nonsmokers with regular menstrual cycle, the OR was 5.98 (95% CI 3.38-10.56) for smokers with irregular one, and compared to nonsmokers nulliparae the OR for smokers parae was 4.77 (95% CI 3.12-7.29).

CONCLUSIONS

Irregular menstrual cycles and parity were related to increased AMI risk, mainly among pre-/peri-menopausal women and among smokers.

Does parity affect mortality among parous women?

OBJECTIVE

To find out whether there is an association between parity and mortality.

DESIGN

Prospective cohort study.

SETTING

Northern Finland, 1966-2001.

PARTICIPANTS AND METHODS

12,055 women in the two northernmost provinces of Finland were followed up from pregnancy in 1966-2001, the coverage percentage being 96%. The data on age, smoking, body mass index, socioeconomic position, age at menarche and age at first birth were collected during pregnancy, and data on deaths were obtained from the National Cause of Death Statistics, maintained by Statistics Finland. The Cox proportional hazard model was used to estimate relative mortality between parity groups.

RESULTS

Total mortality was lowest among the women with 2-4 children (reference group). High parity was associated with an up to twofold risk of mortality from vascular complications, but after adjustment for all background factors, this significance disappeared. Mortality from haemorrhagic stroke was fourfold higher among the women with > or = 10 births compared with those of the reference group. No differences in cerebral infarction or total cancer mortality were seen between the groups. Primiparity was associated with increased mortality from accidental death (relative risk 2.6, 95% confidence interval 1.6 to 4.4).

CONCLUSIONS

High parity was associated with an increased risk of mortality from vascular complications, especially haemorrhagic stroke, and primiparity with an increased risk of accidental death.

Relation of Parity With Common Carotid Intima-Media Thickness Among Women of the Study of Health in Pomerania

Background and Purpose— Metabolic and hormonal changes associated with pregnancy and childbirth are assumed to contribute to the development of cardiovascular disease among women. We analyzed the association of parity with common carotid intima-media thickness (IMT), which has a predictive value of subsequent myocardial infarction and stroke.

Methods— The Study of Health in Pomerania (SHIP), an epidemiological study of the general population in the northeast of Germany, included 1195 women aged 45 to 79 years. Mean and maximum far-wall IMT of the common carotid arteries were assessed by high-resolution ultrasound. All women were comprehensively characterized as to their reproductive history as well as to socioeconomic, behavioral, and biological risk factors.

Results— There was a U-shaped association between the number of children (from 0 to ≥4) and mean and maximum IMT. Nulliparous women had the highest age-adjusted mean (0.81 mm [95% CI, 0.78 to 0.84]) and maximum IMT (1.04 mm [95% CI, 1.00 to 1.09]), and women with single parity the lowest (mean IMT, 0.73 [95% CI, 0.72 to 0.74]; maximum IMT, 0.91 mm [95% CI, 0.89 to 0.93]; P <0.001 versus nulliparity for both parameters). Stepwise multivariate adjustment for socioeconomic factors, lifestyle variables, and biological variables attenuated the magnitude of this association yet significance remained.

Conclusions— Nulliparity and higher number of children are associated with increased carotid IMT. These findings add support to the hypothesis of a link between the reproductive history of women and cardiovascular disease.

Estrogen protection against coronary heart disease: Are the relevant effects of estrogen mediated through its effects on uterus – such as the induction of menstruation, increased bleeding, and the facilitation of pregnancy?

Women in the age group of 20-50 are shown to have much less susceptibility to Coronary Heart Disease (CHD) and other atherosclerotic diseases as compared to men. Exact cause of which is not precisely known and estrogen is constantly shown to be associated with this phenomenon. Improvement of serum HDL concentration and improvement of endothelial functions are some of the proposed mechanisms through which estrogen is believed to mediate this effect. Estrogen therapy however has failed to protect women with bilateral oophorectomy and hysterectomy. Similarly inability of endogenous estrogen to protect women, who have undergone hysterectomy with functioning ovaries from CHD, questions the currently accepted mechanisms through which estrogen brings about these protective effects. Ineffectiveness of estrogen therapy as prophylaxis against CHD in men further questions the credibility of the currently accepted protective mechanisms of estrogen. Estrogen has variety of effects of on uterus, to induce menstruation, to induce bleeding, facilitative role in pregnancy, fetal growth and development. As these physiological effects either directly or indirectly result in loss of cholesterol from cardiovascular compartment, it is proposed that cholesterol-losing effects of estrogen are more important than its presently believed beneficial effects. The small amount that is lost causes movement of cholesterol from atheroma towards plasma and thereby retards the progress of atherosclerosis. These cholesterol-losing effects of estrogen enable women to enjoy freedom from CHD during their reproductive age, as compared to men of comparable age group. Statistical data obtained from blood donors indirectly support the proposed hypothesis.

Long-term plasma lipid changes associated with a first birth: the Coronary Artery Risk Development in Young Adults study

Previous studies have reported declines in high density lipoprotein (HDL) cholesterol 1-2 years after pregnancy. In 1986-1996, the authors prospectively examined the association between childbearing and changes in fasting plasma lipids (low density lipoprotein, HDL, and total cholesterol; triglycerides) among 1,952 US women (980 Black, 972 White) in the Coronary Artery Risk Development in Young Adults study. Repeated-measures multiple linear regression was used to examine lipid changes over three time intervals (baseline to years 5, 7, and 10) in time-dependent follow-up groups: P0 (0 pregnancies), P1 (>/=1 miscarriages/abortions), B1 (1 birth), and B2 (>/=2 births). Means stratified by race and baseline parity (nulliparous or parous) were fully adjusted for study center, time, height, baseline diet, and other baseline and time-dependent covariates (age, smoking, education, weight, waist circumference, alcohol intake, oral contraceptive use, physical activity, short pregnancies). For both races, fully adjusted HDL cholesterol declines of -3 to -4 mg/dl were associated with a first birth versus no pregnancies during follow-up (p < 0.001). Higher-order births were not associated with greater declines in HDL cholesterol (B2 similar to B1, no association among women parous at baseline). In Whites, total and low density lipoprotein cholesterol declines were associated with follow-up births. HDL cholesterol declines of -3 to -4 mg/dl after a first birth persisted during the 10 years of follow-up independent of weight, central adiposity, and selected behavior changes.

Is the association between parity and coronary heart disease due to biological effects of pregnancy or adverse lifestyle risk factors associated with child-rearing? Findings from the British Women's Heart and Health Study and the British Regional Heart Study

BACKGROUND

Parity is associated with coronary heart disease (CHD) risk. In the present study, we assessed the associations between number of children and CHD in both women and men.

METHODS AND RESULTS

A total of 4286 women and 4252 men aged 60 to 79 years from 24 British towns were studied. Number of children was positively associated with body mass index and waist-hip ratio in both sexes. In women but not in men, number of children was inversely associated with high-density lipoprotein cholesterol and was positively associated with triglycerides and diabetes. For both sexes, similar "J" shaped associations between number of children and CHD were observed, with the prevalence lowest among those with 2 children and increasing linearly with each additional child beyond 2. For those with at least 2 children, each additional child increased the age-adjusted odds of CHD by 30% (odds ratio, 1.30; 95% confidence interval, 1.17 to 1.44) for women and by 12% for men (odds ratio, 1.12; 95% confidence interval, 1.02 to 1.22). Adjustment for obesity and metabolic risk factors attenuated the associations between greater number of children and CHD in both sexes, although in women some association remained.

CONCLUSIONS

Lifestyle risk factors associated with child-rearing lead to obesity and result in increased CHD in both sexes; biological responses of pregnancy may have additional adverse effects in women.

Parity and carotid artery atherosclerosis in elderly women: The Rotterdam Study

BACKGROUND AND PURPOSE

It has been postulated that physiological changes in the cardiovascular system, lipids, and glucose metabolism during pregnancy may increase subsequent risk of cardiovascular disease. Examination of the association between parity and risk factors for atherosclerosis may contribute information regarding possible mechanisms.

METHODS

The relationship of parity with cardiovascular risk factors and the presence of carotid atherosclerosis was examined in the Rotterdam Study, a population-based study comprising 4878 women aged 55 years and older. Carotid atherosclerosis was assessed by ultrasonographic detection of plaques in the common carotid artery and bifurcation. Logistic regression models were used to compute odds ratios and 95% confidence intervals, adjusted for confounding factors.

RESULTS

Parity was inversely associated with high-density lipoprotein cholesterol, and alcohol intake. Parity was positively associated with body mass index, total/HDL cholesterol ratio, insulin resistance, age at menopause, and socioeconomic status. Relative to nulliparous women, parous women had 36% (9% to 71%) greater risk of carotid atherosclerosis, rising to 64% in women with >/=4 children (19% to 127%). Adjustment for known cardiovascular risk factors, including insulin resistance and current lipid levels, did not diminish the magnitude of this association.

CONCLUSIONS

Data demonstrated that there is a positive association between parity and risk of carotid artery plaques in elderly women and, further, that high parity is associated with lower HDL cholesterol levels and higher glucose/insulin ratios long after childbearing has ceased.

Reproductive history and cardiovascular disease risk in postmenopausal women: a review of the literature

OBJECTIVES

It is widely believed that oestrogen protects postmenopausal women from cardiovascular disease. It is unknown, however, whether reproductive history, which affects endogenous oestrogen levels during a woman's life, also influences cardiovascular disease risk in postmenopausal women. We present an overview of the studies which investigate the relationship between reproductive history and risk for cardiovascular disease in women.

METHODS

We conducted a Medline search of literature pertaining to age at menarche, age at menopause, parity and gravidity, breast-feeding, and length and regularity of the menstrual cycle in relation to cardiovascular diseases. Data extraction and synthesis were performed by comparing odds ratios and relative risks presented or calculated.

RESULTS

Age at menarche was not found to influence cardiovascular disease risk, while menstrual cycle irregularity was associated with this risk. The studies pertaining to parity presented conflicting results: protection against as well as an increase in the risk of cardiovascular disease were found in parous women. Pregnancy loss appeared to be related to cardiovascular disease risk. Age at menopause proved to be the reproductive factor most clearly related to cardiovascular disease risk.

CONCLUSIONS

Only menstrual cycle irregularity, pregnancy losses, and age at menopause are possibly related to cardiovascular disease risk in postmenopausal women. All reproductive factors need to be studied together in order to assess reproductive history in a proper manner. Research of this kind will be essential if we are to further increase our knowledge regarding the nature of the effects of endogenous oestrogen on cardiovascular disease.