Women who take hormone replacement therapy (HRT) to ease menopause symptoms like hot flashes and night sweats may be no more likely to die prematurely than women who don't take hormones, a new study suggests.
Many women have been reluctant to use hormones for menopause symptoms since 2002, when the federally funded Women's Health Initiative (WHI) study linked the treatments containing man-made versions of the female hormones estrogen and progestin to an increased risk of breast cancer, heart attacks and strokes.
The current study, however, looked at longer-term data from the WHI study and found no increased risk of death from all causes, or from cancer or cardiovascular issues in particular, associated with hormone use.
"Women seeking treatment for distressing hot flashes, night sweats or other menopausal symptoms may find the mortality results reassuring," said lead study author Dr. JoAnn Manson of Brigham and Women's Hospital and Harvard Medical School in Boston.
Women go through menopause when they stop menstruating, typically between ages 45 and 55. As the ovaries curb production of the hormones estrogen and progesterone in the years leading up to menopause and afterward, women can experience symptoms ranging from irregular periods and vaginal dryness to mood swings and insomnia.
For the study, researchers looked at data on 27,347 women ages 50 to 79 who joined two WHI trials between 1993 and 1998 and were followed through 2014. One trial tested estrogen alone against a placebo, or dummy pill, while the other trial tested estrogen taken in combination with progestin.
Women were 63 years old on average when they joined the trials and had already gone through menopause. They took hormones or a placebo for five to seven years and were followed for a total of 18 years altogether.
During the study period, 7,489 women died.
Death rates were similar - at about 27 percent - among women who took hormones and women who didn't, researchers report in JAMA.
Younger women in the study appeared to have better survival odds with HRT. Over the initial five to seven years when women were randomly assigned to take hormones or a placebo, death rates were about 30 percent lower among women aged 50 to 59 when they took HRT than when they didn't.
For women who started hormones in their 60s or 70s, however, there wasn't a meaningful difference in death rates according to whether they got the treatment or a placebo during the initial years of the study.
After 18 years, including both the treatment period and a decade or more of follow-up, women's age when they joined the study no longer appeared to significantly influence death rates.
One limitation of the study is that the WHI didn't look at different dosages of hormone pills, and the findings may be different for other dosages or different types of therapy such as gels or creams or skin patches.
Still, the current study should ease concerns raised by earlier results from the WHI trials that an increased risk of breast cancer or heart attacks might translate into higher long-term mortality rates, said Dr. Melissa McNeil, author of an accompanying editorial and a women's health researcher at the University of Pittsburgh.
Taking a combination of estrogen and progestin is associated with an increased risk of breast cancer, but advances in screening and treatment since the WHI started now mean these tumors are unlikely to be fatal, McNeil said by email.
With additional years of follow-up, it also appears that the increased heart attack risk associated with HRT in the initial results from the WHI trials is limited to older women, McNeil added.
"Hormone therapy has been in and out of favor - first it was good for all menopausal women, then it was dangerous for all women," McNeil said. "The take-home message now is that for the right patient, hormone therapy is safe and effective."