Association of reproductive history with hypertension and prehypertension in Chinese postmenopausal women: a population-based cross-sectional study.

Hypertension and prehypertension may have important roles in the etiology of cardiovascular disease. However, the risk factors of hypertension and prehypertension have not been thoroughly elucidated to date. This study intended to explore the relative effects between reproductive history and the prevalence of hypertension and prehypertension. A population-based cross-sectional survey of postmenopausal women (n=6252), aged 41-93 years, was conducted from August 2013 to August 2015. All subjects, selected by the multistage random sampling method in Henan province, were categorized as normotension, prehypertension and hypertension according to blood pressure (BP) levels. Ordinal logistic regression models were used to estimate the risks of prehypertension and hypertension with three categories of BP as dependent variables. Hypertension was associated with a positive history of induced abortion (adjusted odds ratio (OR)=1.190, 95% confidence interval (CI): 1.020, 1.388), but there was no association between hypertension and a positive history of spontaneous abortion (adjusted OR=1.126, 95% CI: 0.973, 1.303) after adjusting for age, alcohol consumption, education status, smoking, body mass index, physical activity and occupation. Compared with women with one or no children, those with two or three children were at a lower risk of hypertension (adjusted OR=0.605, 95% CI: 0.434, 0.845). In addition, individuals with an age of menopause between 46 and 51 years may have a decreased risk of both prehypertension and hypertension, especially in terms of systolic BP. In conclusion, a positive history of induced abortion may be a predictive risk factor for hypertension and prehypertension. However, a menopausal age of 46-51 years or having two children may be protective factors against hypertension and prehypertension.