Number of parity/live birth(s) and cardiovascular disease among Iranian women and men: Results of over 15 years of follow-up.

Abstract

Background: Most previous studies, conducted in non-Middle Eastern populations, have suggested that 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, included 3929 women and 2571 men aged ≥ 30 years, Data for number of parity/live birth(s) were obtained by standard questionnaire. Participants were then annually followed for CVD events. Multivariate 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 2 live births. Among women in multivariate 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, multivariate 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 of this issue in the Middle East and North Africa region, a region with 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.

Live birth/parity number and the risk of incident hypertension among parous women during over 13 years of follow‐up

“…We considered live birth/parity number of two as the reference group, given that this number was associated with the lowest risk for CVD event among Iranian women. 13 In the current study, the selection of confounders was derived from our recent study among the Iranian female population. 3 It should be noted that we used the baseline data of the covariates.…”

“…7 Moreover, physiologic cardiometabolic changes (weight gain, insulin resistance, increased plasma glucose, and dyslipidemia) and complications that women might experience during pregnancy exert potential short-and long-term effects on postpartum outcomes, especially cardiovascular ones. [8][9][10][11][12][13] Most of the previous findings of the effect of live birth and parity on BP level or hypertension were limited to cross-sectional studies with inconsistent results. Although some previous studies suggested that parity can have lowering effects on BP level, 14,15 many more have reported that as the live birth or parity number increased, the prevalence of hypertension became higher.…”