Hot Flashes and Your Heart: What's the Connection?

Most women describe hot flashes as annoying, embarrassing and uncomfortable, while doctors have always viewed them as relatively benign. However, new research published this week in the Journal of the American Medical Association (JAMA) indicates that women who have lots of bothersome hot flashes or night sweats after menopause may be at increased risk for heart disease. The study also found that older women who still have severe hot flashes turned out to be the hormone-therapy users who were at greatest risk for heart attacks. While there was a correlation between women who had significant hot flashes and those with risk factors like high blood pressure or high cholesterol, this didn't completely explain their increased risk of having a heart attack while on hormone therapy.

The new study also included some relatively good news for younger women. It seemed to confirm earlier research findings that using hormone therapy for a few years right after menopause to deal with moderate to severe hot flashes and night sweats does not increase these women's risk of heart attacks. Researchers say that, generally, the longer it's been since a woman reached menopause, the more likely it is that using hormone therapy to treat hot flashes will increase her risk of having a heart attack. However, the study also confirmed that all postmenopausal hormone users face an increased risk of stroke, and all those using a combination of estrogen and progesterone have an increased risk of breast cancer.

The JAMA study includes the latest refinements on the mammoth federal Women's Health Initiative (WHI) studies. It was the WHI that first alerted women in 2002 that hormone therapy did not prevent heart attacks after menopause as commonly believed, but actually increased the risk of heart problems, stroke, blood clots and breast cancer in many women. To achieve the statistical power required to conduct this latest, detailed analysis, researchers combined data from the estrogen-only as well as the combined hormone therapy arms of the WHI study, which included more than 27,000 women in their 50s, 60s and 70s. While the study had some technical problems, researchers said its implications were still worth serious consideration.

To better understand the new research, NEWSWEEK's Pat Wingert talked to lead author, Dr. Jacques Rossouw, chief of the WHI Branch at the National Heart, Lung and Blood Institute. Excerpts:

NEWSWEEK: This latest analysis seems to add further evidence that using hormone therapy does not prevent heart disease in postmenopausal women.
Dr. Jacques Rossouw: That's right. Overall, it's very important to say upfront that this study does not change any of our previous major findings. For the overall study population, taking hormone therapy does not reduce your risk of heart attacks and it does increase your risk of stroke. We saw in the original clinical trials, indications that the risk of coronary heart disease and stroke varied by age group and the length of time since they had reached menopause, but the numbers were too small for us to be sure. Recognizing that, we thought we could get a firmer estimate if we combined the data of both original studies.

The results of this new combined analysis still indicate that you should not take hormone therapy for the prevention of heart disease. But it also indicates that there is not much increased risk of heart attack if you start it when you're younger, or start it within 10 years of reaching menopause, as long as you stop within four or five years. This means that if a woman wants to start hormone therapy to relieve really bad symptoms for a few years, immediately or shortly after she reaches menopause, that's a reasonable option. So in a sense, that's good news. But because we found an association between hot flashes and the greater likelihood of having various risk factors, she will need to closely monitor her blood pressure, her cholesterol, her glucose levels and body weight.