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.