Association of Body Mass Index with Reinfarction and Survival After First Myocardial Infarction in Women

Few studies have reported the association between adiposity and prognosis after myocardial infarction (MI) or the gender differences in these associations for women and men. The purpose of this study was to examine the association between body mass index (BMI) and reinfarction and long-term survival after the first MI in women. We conducted a retrospective cohort study of 691 women (mean age 66.2 years) who survived the first MI to hospital discharge between January 1, 1980, and December 31, 1991, while enrolled at the Group Health Cooperative of Puget Sound. Reinfarctions (n = 127) and deaths (n = 166) through December 31, 1993, were then identified. Weight and height were ascertained from medical records, and BMI (weight in kilograms divided by square of height in meters) was calculated. Relative risks were determined using proportional hazards regression. For each 1-unit increase in BMI, the relative risk of reinfarction increased by 5% (relative risk 1.05, 95% confidence interval 1.02 to 1.08). This association was unaffected by smoking and was attenuated, but not eliminated, after adjustment for diabetes and hypertension (relative risk 1.03, 95% confidence interval 1.00 to 1.07). The association between risk of all-cause mortality and BMI had a U-shaped distribution. When the analysis was limited to women with no history of cancer or pulmonary disease who had survived for 1 year, there was no association between BMI and all-cause mortality. This study provides evidence that, in women, higher BMI scores are associated with increased risk of reinfarction after a first MI.