Too Much of This Might Double Your Risk of Dementia

CorbisThe female hormone estrogen keeps a woman’s sex drive humming and her menstrual cycles regular, but women with naturally high levels — especially those who are diabetic — are at risk for dementia, according to a study of 5,644 post-menopausal women published January 29 in the journal Neurology. French researchers found that the risk for dementia more than doubled for women over the age of 65 who had high estrogen levels. For diabetic women, the risk of dementia increased 14-fold. Scientists measured the women's blood levels of estrogen and then checked them again four years later, comparing the estrogen levels they had observed in 543 women without dementia with those in 132 women who had been diagnosed with it.

Estrogen therapy (medicine to replace the female hormones that the body stops making after women reach menopause, usually around age 50) has long been hailed for soothing the symptoms of menopause, but there’s been debate in the science world in regard to its safety. In 2002, the National Institutes of Health released a 15-year study of post-menopausal women enrolled in clinical trials of hormone therapy and found that a combination of estrogen and progestin increased the risk of heart disease, breast cancer, stroke, and blood clots. As a result of the findings, women who underwent hysterectomies (a surgery that can often jumpstart the process of menopause) feared turning to estrogen therapy to relieve their symptoms, despite researchers' claims that the study results didn't apply to women who had had hysterectomies. "We don't have hard numbers on how many women take estrogen therapy; however, the National Institutes of Health study scared many from taking it," Jazmin Acosta, a neuroscientist at the Mayo Clinic, tells Yahoo Shine. "Although that's starting to change."

More on Yahoo Shine: 5 Health Habits That Reduce Your Risk of Dementia

According to a story published by Bloomberg News, scientists are now studying how estrogen affects cognitive function and some medical experts are discouraging patients from taking it as a supplement because of findings linking the hormone to cancer and blood clots.

More on Yahoo: Diet, Exercise Key for Improving Heart Health

Although Yahoo Shine could not reach the study authors for comment, lead study researcher Pierre-Yves Scarabin, director of research at the French Institute of Health and Medical Research in Villejuif, France, told in an email, “This study, together with other current data, challenge this dogma that the hormone is beneficial. Mechanisms underlying this association remain to be clarified.”

According to Acosta, the results aren't that clear-cut. "Estrogen is composed of both estradiol, which is good for cognition, and estron, which is harmful to cognition. So while the women in the study may have had high estrogen levels as a whole, the French researchers didn't look at specifics," she says. "The study found an association; however, it's tough to directly say that high estrogen levels cause dementia."

It's worth noting that the French researchers didn't study women undergoing hormone therapy but instead looked only at women with naturally high levels of estrogen. If you’re concerned about the effects of estrogen, of course your best bet is to talk to your doctor. "We do know that women benefit from taking estrogen replacement therapy the earlier they take it, says Acosta. "However, it's still an evolving field of science that we're learning about."

More on Yahoo Shine:
The Surprising Truth About Men and Depression
The 7 Worst Health Habits Ever
7 Surprising Ways You're Ruining Your Teeth