However, oral hormone therapy was linked to mood benefits, the research found.
“Hormone therapy is not a panacea, as it was once portrayed to be,” said study researcher Carey Gleason, an associate professor at the University of Wisconsin School of Medicine and Public Health. “On the other hand, it is not a poison.”
Previously, the Women’s Health Initiative (WHI) Memory Study ”suggested that hormone therapy was associated with cognitive harm for women age 65 and older,” Gleason said. That study also found increased risk of heart attack, strokes and blood clots in postmenopausal women, according to the U.S. National Heart, Lung, and Blood Institute (NHLBI).
Today, experts generally recommend that hormone therapy be used for the shortest time possible at the start of menopause, at the lowest dose, just long enough to manage hot flashes and other symptoms, according to the NHLBI.
Gleason’s team wanted to look at hormone therapy’s effects on thinking and memory in younger women who recently started menopause.
The researchers randomly assigned almost 700 women who had recently started menopause to receive either estrogen pills and progesterone, transdermal (skin) estradiol patches and progesterone, or placebo pills and patches. They followed the women for up to four years, tracking their memory, thinking skills and moods. On average, the women were age 53 when they started the study. Their last menstrual period averaged slightly more than one year earlier.
Compared to women on the placebo, women on hormone therapy didn’t score much differently on tests of thinking and memory, the researchers found. But women on oral hormones did see improvements in depression and anxiety symptoms, according to the study. Women on hormone patches didn’t see the same benefit, the study noted.
These findings only apply to women who recently started menopause and have a low heart disease risk, the study authors wrote.
The study results don’t offer any information about the effects of hormone therapy taken for longer than four years, the researchers said. Additionally, most of the women in the study were white and well-educated, so the results may not apply to the U.S. population as a whole.
However, the study results do provide reassurance for the group studied, said Pauline Maki, professor of psychiatry and psychology at the University of Illinois at Chicago.
“This study tells a woman who is on hormone therapy that there is no harm to her memory,” said Maki, who wasn’t involved in the study. However, “there is lingering doubt [overall] about the safety of hormone therapy for the brain from the Women’s Health Initiative.” The new study “can bring comfort to women because both showed that hormone therapy is neutral for cognition,” she said.
Teasing out the effects of hormone therapy gets complicated, she added, because hot flashes can also disrupt sleep and affect the brain and thinking skills.
Gleason said the take-away message from her research: “If a woman chooses to manage her menopausal symptoms with hormone therapy, she can be reassured that she is not harming her cognition. Moreover, she may also experience some mood benefits.”
The study, which was funded by the U.S. National Institutes of Health, was published June 2 in PLOS Medicine.