Number of Children and Risk of Cardiovascular Disease in Japanese Women: Findings from the Tohoku Medical Megabank

Aim: Cardiovascular disease (CVD) is the second largest cause of death in Japanese women. Pregnancy and childbirth are events that put a strain on the cardiovascular system. When postpartum weight retention is insufficient, weight gain due to fat deposition during pregnancy might lead to obesity. Thus, we examined the effects of body mass index (BMI) in middle and older ages and the number of children on CVD and metabolic disorders. Methods: From the Tohoku Medical Megabank database, we used data from 32,000 women aged ≥ 50 years. This database contains obstetrical history, medical history, and laboratory data obtained once from 2013 to 2015. Results: The mean age of participants was 64.2 years, and 47.7% of women had two children. Compared with nulliparous women, those who had a higher number of children had higher BMI and systolic blood pressure. The prevalence of CVD was highest in obese class I (30 kg/m(2) ≤ BMI) women with three or more children and the prevalence of hypertension was high in pre-obese (25 kg/m(2) ≤ BMI ＜30 kg/m(2)) and obese class I women with children. Conversely, the prevalence of diabetes and proportion of women whose HbA1c values were ＞6.5% was highest in obese class I women with no children. Conclusion: In this study, we found that not only BMI but also the number of children influenced the health status of middle- and older-aged women, suggesting the importance of childbirth history in the health management of women.