For Linnea Duvall, a marriage and family therapist who lives and works in Santa Monica, Calif., the symptoms of menopause started when she turned 50. She felt more irritable and a smidge heavier, and she started waking up two to three times a night.

And then she had a hot flash.

"It felt like a nuclear bomb went off right behind my belly button," she says. "The radiation went out to my fingertips, the tops of my toes, the top of my head and the ends of my hair."

But Duvall would not consider hormone therapy to control the flashes. She was terrified. She says she can sum up her fear in two words: "breast cancer."

To understand why she feels this way, we have to look back a few decades to a time when many postmenopausal women were taking hormones to treat symptoms. At the time, hormones were thought of as something of an elixir of youth that could also prevent chronic disease. So women took hormones indefinitely. But a huge study in 2002 changed everything.

Known as the Women's Health Initiative, it found that taking estrogen plus progestin hormone replacement therapy actually increased a woman's risk of heart disease and breast cancer. The study had a huge effect. Within months the number of women taking hormones in the U.S. dropped by almost half. Today, only about 10 percent of women ages 50 and over are on hormone therapy.

That was a huge overreaction, according to Dr. Wulf Utian, director of the North American Menopause Society, particularly in light of more recent findings. A more detailed analysis of the Women's Health Initiative data found that age really made a difference in heart disease risk. For women who started hormone therapy between the ages of 50 and 59, there was a protective benefit, says Dr. JoAnn Manson, one of the lead investigators of the study and a professor of medicine at the Harvard T.H. Chan School of Public Health.

Women who take hormones earlier after the onset of menopause may experience less plaque, blood vessel blockage and atherosclerosis, Manson says, and possibly even a reduced risk of heart attack. But for women over the age of 60, the benefit seems to disappear. This is probably because older women already have plaque buildup, Manson says.

Researchers in Denmark also found that age makes a difference. They looked at 1,000 healthy women between the ages of 45 and 58. The women who took hormones experienced significantly reduced risk of mortality, heart failure and heart attack.

Today, menopausal women are young in the scale of things, says Dr. Utian, noting that menopause typically starts between age 45 and 60. If women start hormones within a few years of menopause or even a few years before, he says, there are numerous benefits beyond controlling hot flashes. These benefits include reduced risk of bone fractures, reduced risk of diabetes and, for many women, an overall boost in their quality of life — meaning better sleep, maintenance of libido and more comfortable sex.

"In my opinion, the best recommendation would be for some form of hormone therapy," says Utian.

But here's the worry. Studies do confirm an increased risk of breast cancer among women taking hormones, regardless of age. Manson says any risk is worrisome, but it's important to put this risk in perspective and understand that it is actually small.

"For every 1,000 women per year not using hormone therapy, about three would develop breast cancer," Manson says. "And among every 1,000 women using hormone therapy, about four of them would develop breast cancer, so that's about one extra case of breast cancer per 1,000 women per year on hormone therapy."

This is where things get tricky. There is no consensus in the medical community on whether the symptom relief is worth the extra risk. Different doctors interpret risk differently. And if you're a breast oncologist like Dr. Rowan Chlebowski at Harbor UCLA Medical Center, any risk is too much.

"It's a disease that I see every day," Chlebowsi says. "So I think that's something to be avoided."

Chlebowski adds that hormone therapy also makes it more difficult to read mammograms, since hormones make the breast denser. If mammograms are more difficult to read, it's harder to diagnose breast cancer in its earliest stage when it's most treatable.

So bottom line — this really is an individual decision between a woman and her doctor, a decision based on how much risk a woman can tolerate in favor of symptom control and other potential benefits. Researcher Joann Manson says if a woman chooses hormone therapy, then the lowest possible dose for the shortest amount of time is probably safe for most women.

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