Endometriosis is associated with a significantly increased risk of coronary heart disease, at least in part because of one of its principal treatments – hysterectomy/oophorectomy, according to a new analysis of the Nurses’ Health Study II.
In what the researchers described as the first large prospective study to examine this possible association, the link between endometriosis and coronary heart disease (CHD) was mediated by patient age.
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Women with endometriosis had a higher incidence of CHD than those without the gynecologic disorder until they reached their late 50s; after that, the two populations had similar CHD rates, wrote Fan Mu, Sc.D., of the department of epidemiology, Harvard T. H. Chan School of Public Health in Boston, and her associates (Circ Cardiovasc Qual Outcomes. 2016 Mar 29. doi: 10.1161/circoutcomes.115.002224).
“This association may have important clinical and public health implications among women in their early 40s to early 50s,” the researchers wrote. “It is possible that the observed increased risk associated with surgical menopause from hysterectomy/oophorectomy among women with endometriosis started to diminish with age partially because nearly every woman had reached menopause by the age of 55 years.”
The researchers chose to study this topic because endometriosis has been linked to chronic systemic inflammation, oxidative stress, and adverse lipid profiles, factors that also play key roles in the pathogenesis of atherosclerotic CHD. They assessed the incidence of myocardial infarction, angina, and the combined outcome of coronary artery bypass graft (CABG)/angioplasty/stenting using data from the Nurses’ Health Study II, a prospective cohort study involving 116,430 women, aged 25-42 years at baseline in 1989, who were followed for approximately 20 years.
A total of 5,296 of the study participants had laparoscopically confirmed endometriosis at baseline, and another 6,607 developed the disorder during follow-up. There were 1,438 incident cases of CHD during follow-up.
Compared with women who didn’t have endometriosis, those who did showed increased relative risks for myocardial infarction (1.63), angiographically confirmed angina (2.07), CABG/angioplasty/stent (1.49), and combined CHD (1.73). The results remained statistically significant after the researchers adjusted for potential confounders.
About 42% of this association was statistically accounted for by the greater frequency of hysterectomy/oophorectomy among women who had endometriosis and the earlier age of these surgeries among women with endometriosis. Women who underwent the surgery had an absolute incidence of CHD of 139 per 100,000 person-years, compared with an incidence of 60 per 100,000 person-years among the women who didn’t have hysterectomy/oophorectomy.
“Physicians need to consider the potential long-term impact that the surgeries may cause and weigh the risks and benefits of the treatment in dialogue with patients, particularly with respect to endometriosis where pain recurrence risk remains,” the researchers wrote. “Although oophorectomy confers obvious prevention for ovarian cancer, with which endometriosis has been associated, CHD is the leading cause of mortality and morbidity in women in the United States and United Kingdom.”
The study was supported by the National Institutes of Health. The researchers reported having no relevant financial disclosures.