Cardiovascular disease and cancer risk following bilateral oophorectomy: A population-based study in Rochester, Minnesota

Objective. To evaluate mortality as well as the occurrence of coronary heart disease, stroke, and cancer following bilateral oophorectomy. Additionally, women who subsequently received estrogen replacement therapy (ERT) were compared to those who did not. Design. Retrospective (historical) cohort study of outcomes after bilateral oophorectomy among those exposed to ERT and those not exposed. Setting. Population-based study in Rochester, Minnesota. Patients. Rochester women (N = 457) aged 30-55 years at the time of bilateral oophorectomy for a benign condition during 1950-1979. Results. All cause mortality was decreased among these women and use of ERT did not reduce the risk of death further. In 7,425 person-years of follow-up, the number of women with cardiovascular disease and cancer was no different from expected. Although there was a trend toward less coronary heart disease and more breast cancer among women on ERT, the women prescribed ERT tended to be leaner, had less hypertension, and more often drank alcohol. Conclusion. There was no evidence of an increased risk of adverse cardiovascular disease or cancer outcomes following bilateral oophorectomy but, because of limited power and residual confounding, observational studies such as this may not be optimal for assessing the risks and benefits of ERT in this group of women.