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

Abstract

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.

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

“…Adjustment variables were chosen primarily based on findings from previous studies as potential confounding variables. 8,16 They were age (continuous), body mass index (BMI; quintiles), sleep duration (<5, 6, 7, 8, and ≥9 hours=day), walking habit (almost never, 0.5, 0.5-0.9, and ≥1 hours=day), exercise (almost never, 1-2, 3-4, and ≥5 hours= week), smoking status (never, past, and current smoker), alcohol intake (never, past, and current drinker), education (primary school, junior high school, high school, and college), occupation (fulltime job, part-time job, self-employed, housewife, no job, and other), marital status (married, widowed, divorced, and never married), perceived mental stress (low, moderate, and high), history of hypertension (yes and no) and history of diabetes (yes and no). Furthermore, the number of delivery was also adjusted in the analysis for association between maternal age at first delivery and CVD mortality.…”

“…Our results were consistent with previous findings of U-shaped association between the number of deliveries and risk of CVD Reproductive History and Mortality From Cardiovascular Disease mortality. [4][5][6][7][8] Important findings were reported by the censusbased Israel Longitudinal Mortality Study II, which enrolled 62,822 women and showed that both nulliparity and higher number of deliveries were associated with increased risk of CVD mortality. The multivariable HRs of CVD mortality in women aged 45-64 years were 2.43 (95% CI, 1.49-3.96) for nulliparous and 1.64 (95% CI, 1.02-2.65) for eight deliveries.…”

“…The multivariable HRs of CVD mortality in women aged 45-64 years were 2.43 (95% CI, 1.49-3.96) for nulliparous and 1.64 (95% CI, 1.02-2.65) for eight deliveries. 5 In addition, a meta-analysis of 10 cohort studies reporting 16,601 deaths, including five North American studies, the aforementioned Israeli study, and four studies from other countries (Australia, China, Korea, and Finland; one study each), 8 indicated a U-shaped association between the number of deliveries and risk of CVD mortality, with 4 deliveries representing the nadir of risk.…”

“…Some prospective cohort studies have shown a U-shaped relationship between the number of deliveries and risks of CVD incidence 3 and CVD mortality. [4][5][6][7][8] However, other studies have found positive association with risks of CVD incidence 9,10 and CVD mortality, 11 inverse association with risk of CVD mortality, 12 and no association with risk of CVD mortality. 13,14 In addition to the association with the number of deliveries, a number of prospective cohort studies have shown that early maternal age at first delivery was a risk factor for risk of CVD mortality, 4,[14][15][16] but other studies showed no inverse association between maternal age at first delivery and risk of CVD mortality.…”

Multiparity improves outcomes after cerebral ischemia in female mice despite features of increased metabovascular risk

“…Epidemiological data suggest that increasing parity is associated with higher risk of cardiovascular disease (CVD) and stroke and late-life vascular comorbidities, including carotid atherosclerosis (3,4). However, recent reports suggest that parity has a significant protective effect against CVD mortality (5). The effect of parity on outcome following ischemic stroke is yet unresolved.…”