When a woman who is near or has reached the menopause and undergoes a hysterectomy, the ovaries are usually removed. The basis for this is that the ovaries are—or soon will be––nonfunctional and their removal can prevent the development of ovarian cancer. However, a new study has found that removal of the ovaries (oophorectomy) accelerates bone loss and thickening of the carotid artery, which supplies blood to the brain. The study was conducted by researchers at the University of Southern California’s (USC) Keck School of Medicine. The findings were published on February 14 by the American Society for Reproductive medicine (ASRM) and are slated for publication in an upcoming edition of the journal Fertility and Sterility.
As women age, they commonly develop osteoporosis and cardiovascular disease, particularly after menopause. Decreasing levels of hormones affects the severity of both conditions is affected by decreasing levels of hormones. This drop in hormonal level usually occurs naturally as a women enters menopause; however, it can also occur abruptly if the ovaries are surgically removed. The researchers conducted a study to assess the effect of a premenopausal oophorectomy on the rate of loss of bone mineral density and the rate of thickening of the carotid artery in healthy postmenopausal women. Bone mineral density measures osteoporosis and carotid artery thickening is a measurement of cardiovascular health. The investigators theorized that women who retained their ovaries would have a degree of protection against bone loss and vascular thickening, compared to women who had undergone an oophorectomy.
The study group comprised 222 healthy postmenopausal women who lived in the greater Los Angeles area. The woman were at least five years beyond the menopause; they were enrolled in the WISH (Women’s Isoflavone Soy Health) clinical trial, which was conducted from April 2004 through March 2009. The participants underwent scans for bone mineral density at the start of the trial and every year thereafter; in addition, they underwent an ultrasound evaluation of carotid artery intima-media thickness (CIMT) every six months. The WISH trial found no treatment group differences in bone mineral density or CIMT between women who had soy protein supplementation and women who received a placebo. However, data from both the soy protein group and the placebo group were evaluated for the USC study. The data were evaluated from women who did not and those that did undergo an oophorectomy. Data from women who were taking hormone replacement therapy (HRT) or osteoporosis medication were excluded.
The investigators found that the rate of subclinical (symptomless) atherosclerosis progressed faster in women who had undergone an oophorectomy, compared to those who retained their ovaries. Loss of bone mineral density and CIMT progression and BMD loss were greater in women more than 10 years post-menopause who had undergone an oophorectomy.
Take home message:
This study suggests that, despite their lack of estrogen production, postmenopausal ovaries still exert a degree of protection from cardiovascular disease and osteoporosis. Women with a family history of ovarian cancer and/or carry the BRCA1 or BRCA2 mutation will have a benefit from an oophorectomy that outweighs the risks. Women with these gene mutations are also at increased risk for breast cancer, and HRT has been reported to increase the risk of breast cancer. HRT, particularly if it is begun at the time of menopause (or immediately following an oophorectomy in a premenopausal woman) has been reported to reduce bone loss and improve cardiovascular health. For most premenopausal women who have their ovaries removed, the benefits outweigh the risks. Non-hormonal medication is available to decrease and even reverse osteoporosis; however, long-term use is subject to debate. Individual circumstances should be discussed with a board-certified gynecologist or endocrinologist.