A new analysis of the Women's Health Initiative (WHI) trials show that women who had metabolic syndrome before they started hormone therapy had a greatly increased risk of heart attack or dying of heart disease. Women who didn't have metabolic syndrome beforehand showed no increased risk. The study was published this month online in Menopause, the journal of the North American Menopause Society.
"Our findings emphasize the importance of assessing cardiovascular disease risk status when hormone therapy is considered for relief of menopausal symptoms," wrote the WHI investigators who authored the study.
Metabolic syndrome is a group of risk factors that occur together and increase the risk of heart disease, stroke, and diabetes. They include a large waistline, high blood pressure, high blood glucose or diabetes, high triglycerides, or low HDL—the "good cholesterol." Obesity is the key feature, which predisposes women to the others.
In this analysis, a woman was considered to have metabolic syndrome if she had three of any of the five metabolic syndrome features; 269 women met the criteria when they started the trial and were compared with 695 women who did not have metabolic syndrome.
The women who did not have metabolic syndrome showed no increased risk of heart disease, whether they took hormones or not. But the risk of a heart attack or dying of heart disease was more than double for women who had metabolic syndrome and took hormones (either combined estrogen-progestogen or estrogen alone if they had undergone hysterectomy) compared with women who had metabolic syndrome and did not take hormones. Women with metabolic syndrome who took estrogen alone had a smaller increase in risk, but they were still at significantly higher risk than women with metabolic syndrome who did not take hormones.
In the WHI, women took oral formulations of hormone therapy, which were common at the time. Today, smaller doses and other forms, such skin patches or gels, are being used. In addition, women in the WHI were older (average age 66 in this analysis) than the age women usually start hormone therapy for menopause symptoms, such as hot flashes and night sweats. Newer formulations and earlier use of hormone therapy may be safer, but more study needs to be done to find out if having metabolic syndrome makes a difference with these types of hormone therapy.
The study will be published in the March 2013 print edition of Menopause.
Explore further: The Women's Health Initiative: An unforgettable decade