This apparent benefit comes without a heightened risk of cancer or blood clots, the Danish researchers said. These health risks have long been a concern of menopausal women and their doctors when considering hormone therapy.
The study, published in the BMJ, even found evidence of a trend toward a lower risk of breast cancer, although this was not statistically significant, said study author Dr Louise Lind Schierbeck.
However, two doctors not associated with the study said the findings weren't enough to convince them to recommend hormone replacement therapy (HRT) to head off heart problems. But they - and many doctors - would prescribe low doses of the therapy for short durations to treat menopausal symptoms such as poor sleep or hot flashes.
New study on HRT
The new study comes on the heels of two other studies, one finding that HRT was safe for the heart and the other concluding that it did not worsen memory in younger women taking it.
Women have shied away from hormone therapy since the landmark Women's Health Initiative study found elevated risks of breast cancer, heart disease and other health problems among women taking oestrogen plus progestin, a synthetic form of progesterone. That study was halted early because of the results, published in 2002.
For this latest study, about 1 000 women aged 45 to 58 who were recently menopausal or had perimenopausal symptoms, such as hot flashes and irregular periods, were randomly selected to receive either HRT or an inactive placebo.
Participants took the therapy for an average of a decade, at which point they had a 50 percent decreased risk of a cardiovascular event or death, said Schierbeck, who is with Bispebjerg Hospital in Copenhagen. Six years after women had stopped taking HRT, the risk was still reduced 40%, she added.
Schierbeck conducted the study while at Hvidovre Hospital, also in Copenhagen. She said that longer follow-up research is needed to verify the breast cancer results.
This study differs from the Women's Health Initiative (WHI) in several important ways. The women in this study were much younger than in the WHI (an average age of 50 versus 64) and were given a differently formulated oestrogen.
The difference in age and time since menopause were probably the main reasons for the differences in the studies, Schierbeck said.
What the study found
But one analysis from the WHI, which only looked at women younger than 60, also found a reduction in heart disease and death, albeit one that was not statistically significant.
HRT has been shown to lower cholesterol levels, improve blood vessel function and keep body weight down, all of which might contribute to a reduction in heart disease.
Dr Suzanne Steinbaum, director of women and heart disease at Lenox Hill Hospital in New York City, said the new study can offer a "little bit of peace of mind" to women who are "recently postmenopausal who are really symptomatic with mood swings, hot flashes and difficulty sleeping and concentrating."
But, she would not prescribe HRT to prevent heart disease based on these results.
Dr Mary Ann McLaughlin, director of the cardiac health program at Mount Sinai Medical Center in New York City, agreed. "I don't think this is enough to change recommendations," she said.
"I wouldn't recommend HRT to postmenopausal women to reduce heart attacks," McLaughlin added. "These results make me feel more confident that some women may benefit from oestrogen therapy, but until I figure out which particular women those are, I would not recommend a carte blanche giving oestrogen again to prevent heart attacks.
"In the next five years, we'll be able to better define which women would benefit and which would be harmed by oestrogen," McLaughlin said. "We're not there yet."
Schierbeck said that international societies are currently weighing the risks and benefits of hormone replacement therapy, to be able to issue future recommendations.
The menopause dictionary
The U.S. National Library of Medicine has more on hormone replacement therapy.
(Copyright © 2012 HealthDay. All rights reserved.)