LAS VEGAS — A systematic review of the medical literature yielded mixed results concerning the effects of bilateral oophorectomy on the risk of coronary heart disease.
“There's been a concern that bilateral oophorectomy may increase the risk of coronary heart disease because estrogen deprivation might accelerate the rate of atherosclerosis,” Dr. Vanessa Jacoby said at the annual meeting of the AAGL.
Dr. Jacoby and her associates sought to identify all of the available related literature on PubMed and Embase between 1966 and 2007, all related abstracts that were presented at the annual clinical meeting of the American College of Obstetricians and Gynecologists between 1996 and 2006, and reference lists from the retrieved articles. Studies were included if they compared women who had bilateral oophorectomy with a hysterectomy to women who had a hysterectomy and ovarian conservation, naturally menopausal women, premenopausal women, or premenopausal women with no history of hysterectomy or bilateral oophorectomy but unreported or unknown menopausal status. The primary outcome was fatal or nonfatal coronary heart disease.
Nearly 2,000 abstracts were reviewed, said Dr. Jacoby of the department of obstetrics, gynecology, and reproductive sciences at the University of California, San Francisco. From these, 16 observational studies were reviewed in full and 7 were used in the final analysis. No randomized trials were located.
Two studies involving women with a hysterectomy and ovarian conservation showed no significant increased risk of coronary heart disease following bilateral oophorectomy.
One of three studies involving naturally menopausal women did show a slight increased risk of CHD, with a hazard ratio of 1.16 (Circulation 2005;111:1462–70). “But in a subsequent analysis that accounted for the effect of all demographic and cardiovascular risk factors like hypertension, diabetes, and smoking, there was no statistically significant increased risk of coronary heart disease,” Dr. Jacoby said.
One of two studies involving premenopausal women, the Nurse's Health Study, reported an increased risk of CHD, with a relative risk of 2.2 (N. Engl. J. Med. 1987;316:1105–10). “That was only in women who never took estrogen following bilateral oophorectomy, and only in an analysis that accounted for age and smoking,” she said. “But in a subsequent analysis that accounted for other cardiovascular risk factors such as obesity, hypertension, and diabetes, there was no increased risk.”
The other study involving premenopausal women found a significantly increased risk of CHD in women aged 40–44 years who had undergone hysterectomy and bilateral oophorectomy, but not in women aged 45 years and older (Ann. Intern. Med. 1978;89:157–61). One of two studies involving women with no history of hysterectomy or bilateral oophorectomy but unreported or unknown menopausal status showed a significantly increased risk of CHD, but only in women younger than age 60 years (Acta. Obstet. Gynecol. Scand. 1981;106 [Suppl.]:11–5).
A limitation of the analysis, she said, is that the observational studies used “are inherently limited by the potential effect of confounding on the outcome. To that end, our goal is to implement a randomized trial of bilateral oophorectomy so we can have the highest-quality evidence to guide our clinical practice for this very common clinical question.”