Prepregnancy body mass index and cardiovascular disease mortality: The child health and development studies

Objective Overweight early in life may contribute to cardiovascular disease mortality through progression to later life obesity or through a cumulative effect of excess weight. Few studies have investigated the relationship between body mass index (BMI) before middle age and cardiovascular disease mortality in women. Using the Child Health and Development Studies cohort of 11,006 pregnant women recruited between 1959 and 1967, the hypothesis that higher self-reported prepregnancy BMI is associated with increased stroke and coronary heart disease mortality was tested. Methods Cause of death was assessed annually from enrollment through 2007 by linking with California Vital Status Records. Cox proportional hazards ratios for cause-specific mortality for each BMI category were calculated. Results Median follow-up was 37 years with 1839 participant deaths at a mean age of 64.1 years. At higher levels of BMI, participants were older, had higher prevalence of co-morbid conditions, higher parity, and lower family income. In adjusted models, women with higher prepregnancy BMI had increased coronary heart disease mortality compared to those with normal BMI. Women who were underweight, overweight, or obese had higher all-cause mortality. Sensitivity analyses confirmed these results. Conclusions Prepregnancy BMI has a monotonic association with coronary heart disease mortality and a j-shaped association with noncardiovascular mortality.