Hot flashes at younger ages may signal higher heart risk

Women who start having hot flashes in their 40s and early 50s had signs of poorer blood vessel health in a recent study and may be at a higher risk of cardiovascular disease later on, researchers say.

“Hot flashes were considered solely quality of life issues. Few investigators have considered their links with women’s heart health,” lead author Rebecca Thurston of the Women's Biobehavioral Health Laboratory at the University of Pittsburgh told Reuters Health by email.

In their study of 272 postmenopausal women, ages 40 to 60, Thurston and her team found a connection between hot flashes at younger ages and impaired function of the lining of the women’s blood vessels.

The health of the lining, known as the endothelium, is commonly assessed by measuring how well the endothelial cells respond to signals that would ordinarily cause the blood vessel to expand.

In women who were having hot flashes at ages 40 to 53, the endothelial cells lining the artery showed poorer responsiveness to those signals, which is typically an indication of increased risk for cardiovascular disease later in life.

This was not true for women of the same age who were not having hot flashes, nor was the link between hot flashes and endothelial dysfunction seen among older women, ages 54 to 60 years.

None of the women were smokers, and none of them had been diagnosed with any cardiovascular diseases.

Cardiovascular disease is the leading cause of women's death, and hot flashes affect 70 percent of women, Thurston said.

Each hot flash can last about a minute or so, and they occur over the course of a decade for many women. The participants in the study showed an average of six recorded hot flashes per 24-hour period.

For reasons yet unknown, waking hot flashes may indicate a higher risk than hot flashes during sleep, the researchers found.

Whereas previous studies regarding hot flashes and cardiovascular risk were observational and based on reports by the women themselves, this new study involved real-time hot flash monitoring, blood tests and ultrasound measurement of blood flow in the arm. For this reason, the investigators say, their results are superior to previous studies.

The researchers also took into account women’s other cardiovascular risk factors and the lower levels of estrogen found in older women, which itself can cause poorer blood vessel function.

Dr. JoAnn Manson of Brigham and Women’s Hospital and Harvard Medical School in Boston was one of the lead investigators on a 2011 study of participants in the large-scale Women’s Health Initiative which found a similar connection between hot flashes and impaired blood vessel dilation – but in women ages 54 to 60.

“The relationship between menopausal hot flashes and cardiovascular risk remains controversial, and this paper does not provide a definitive answer,” Manson told Reuters Health by email.

“In the present study, an association between hot flashes and impaired blood vessel dilation was found in the youngest women, but not in women aged 54-60 (who were in early-to-middle stages of menopause),” said Manson. “In the Women’s Health Initiative, the largest study to date, the opposite was found: hot flashes in late, but not early menopause, were linked to increased cardiovascular risk. Thus, the hot flashes-cardiovascular disease puzzle continues to be incomplete, with many missing pieces.”

In the meantime, the American Heart Association points out on its website that preventing cardiovascular diseases requires “smart choices.”

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