WINSTON-SALEM, N.C., March 3 (UPI) -- Beginning hormone replacement therapy earlier rather than later in a woman's life might help slow down blood vessel deterioration, researchers reported Monday.
The researchers, at Wake Forest University Baptist Medical Center and Tufts-New England Medical Center in Boston, reviewed several HRT clinical trials conducted over the last 12 years on monkeys at Wake Forest.
They also reviewed results from the Women's Health Initiative -- an ongoing study of 167,000 women ages 50 to 79 -- that showed an increased risk of heart attack for postmenopausal women taking HRT. That conclusion led to recommendations issued last summer that women avoid the therapy to prevent heart disease.
The problem with the earlier assessments, the researchers pointed out, is they were based on data from older women. Administering HRT to younger postmenopausal women could result in a different outcome, they said.
Analyzing the data, the researchers found beginning HRT when a woman's estrogen levels start to decline, at the onset of menopause, protects the heart more than when the therapy is started later in life. The average age of the Women's Health Initiative participant is 63.
"That's a very different thing from taking a woman of 51 (the average age when menopause starts)," Dr. Richard H. Karas, the report's co-author and director of the preventive cardiology center at Tufts, told United Press International. A woman in the WHI on average had gone without estrogen for about 18 years.
"Her body has probably adapted to being in an estrogen-deficient state," Karas said. Starting on hormone therapy that late in life, he explained, probably represents "a shock to the system," and could explain why it might affect the heart and blood vessels adversely.
As the researchers reported in the Winter 2003 issue of Menopausal Medicine, when estrogen was given to monkeys at the beginning of estrogen deficiency or menopause, there was a 70 percent blocking of fatty build-up in the heart arteries. However, animals that received estrogen over a period comparable to six human years later showed no benefit to their cardiovascular system.
This is not to say women who do not begin hormone therapy until age 57 are at risk, Karas cautioned. Rather, the data provide clues to when the window of opportunity might close. He added it is unclear how long younger women need to take hormone therapy to reap the rewards.
"There are many, many unanswered questions about effects of hormone replacement therapy on the heart," Karas said. "There is conflicting information out there and nobody really knows, quote, what the answer is here."
Dr. Nieca Goldberg, a spokeswoman for the American Heart Association and a cardiologist at Lenox Hill Hospital in New York City, warned the report's conclusions should be considered premature because much of the data is based on animal research.
"The results from Wake Forest are interesting, but the research was done in monkeys not women," Goldberg told UPI. "Although we have shown that HRT benefits cholesterol and improves blood vessel flexibility, there is no proof that it prevents heart disease."
Goldberg added: "The Woman's Health Initiative has shown that early observations on HRT did not hold up in the randomized clinical trial."
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(Reported by Katrina Woznicki, UPI Science News, in Washington)
