A more nuanced picture may emerge as researchers re-examine data from massive postmenopausal hormone trials.
Hormone therapy has long been the standard treatment for relieving menopausal symptoms: hot flashes, night sweats, and vaginal dryness.
Until 2002, many clinicians were also recommending it long term to prevent chronic health problems, including heart disease, stroke, and osteoporosis.
There was some evidence that oestrogen might contribute to breast cancer, but except for women at especially high risk for that disease, cardiovascular disease was a more serious concern - a far greater cause of death and disability.
For that reason, most health organisations recommended that postmenopausal women consider taking hormone therapy.
Then, in 2002, the hormonal approach to averting women's later-life ills screeched to a halt. Researchers had to stop the Women's Health Initiative (WHI) randomised trial of oestrogen and progestin (in the form of Prempro) because the hormone combination was actually causing more heart attacks and strokes than a placebo, as well as more blood clots and breast cancer.
Two years later, the WHI's trial of oestrogen alone (Premarin), also ended early, after it became apparent that oestrogen increased the rate of strokes and blood clots without conferring any benefits on the heart.
Although there were some benefits - fewer fractures in both trials and a reduced risk for colon cancer in the combined-hormone trial - they didn't outweigh the risks.
That left hormone therapy back where it started, as a short-term treatment for menopausal symptoms.
Impact and critique of the WHI
Hormone therapy is still the most effective treatment for hot flashes and night sweats. But the WHI results - and the associated media firestorm - left women worried and confused about even such short-term use.
They were told to use hormones only for short periods and at low doses, and hormone therapy prescriptions plummeted. (One study reported a 75% drop between 2002 and 2006.) Yet menopausal women looking for symptom relief shouldn't misinterpret the WHI findings.
These studies were not about short-term management of menopausal symptoms. Moreover, the results aren't above criticism.
New questions have arisen as scientists try to reconcile the findings of earlier observational studies with those of the WHI - a randomised, placebo-controlled trial, considered the "gold standard" type of clinical investigation.
Some critics argue that the WHI results may not apply to the typical woman considering hormone therapy because most of the 27,347 participants were in their 60s and 70s - well past the perimenopausal transition and early menopause (the usual time for starting hormone therapy).
Others say that the risks were overstated. Each year, for example, the women taking Prempro had only six more heart attacks per 10,000 than the women taking a placebo; among younger women, the difference was even less.
Because of these and other concerns, scientists have been re-examining the WHI data and undertaking new trials.
Researchers are also reappraising earlier studies that suggested hormone therapy could prevent cardiovascular disease.
Some scientists now suggest that the cardiac risk and benefit of hormone therapy may depend on a woman's age, particularly the age at which she starts taking hormones.
This new hypothesis doesn't change current recommendations (see chart), but it may reassure perimenopausal and newly menopausal women who are considering short-term hormone treatment for symptom relief.
Heart risk: a matter of timing?
The lack of heart benefits in the WHI contradicts findings from observational studies, such as the Nurses' Health Study, in which participants are followed for years but are not asked to take medications or do anything differently.
In those studies, women have tended to start taking hormones closer to the onset of menopause.
Researchers have observed that these women suffer fewer of the heart problems caused by atherosclerosis (for example, angina and heart attacks) than women who don't take hormones.
The idea that hormone therapy might help protect women from atherosclerosis was biologically plausible.
It's long been recognised that women develop atherosclerosis-related heart problems at an older age than men - after menopause and the decline in oestrogen.
In animal studies, oestrogen has been shown to slow development of atherosclerosis.
So why might oestrogen then increase the risk of heart disease in women who start taking it at an older age? Evidence indicates that oestrogen can destabilise atherosclerotic plaques, the artery-clogging accumulations of cholesterol and debris that are a major source of heart disease.
Oestrogen appears to make plaques more vulnerable to rupture, which can result in a heart attack. Older women are more likely to have developed plaques.
So for them, oestrogen might do more harm than good. It may be that hormone therapy is good for the heart only during a fairly narrow window, when plaques are starting to form but are not fully developed.
Nurses' Health Study researchers found some support for this hypothesis in 2006 in a study undertaken to shed light on the discrepancies between the WHI results and earlier research.
They found a 30% reduction in risk for heart disease among women who began hormone therapy within about four years of menopause, but little or no cardiac benefit for women who started hormones either after age 60 or 10 or more years after menopause.
A reanalysis of the WHI data turned up similar evidence that timing may be a factor.
Investigators reporting in the Journal of the American Medical Association (April 4, 2007) found no increased risk for heart disease among hormone users ages 50 to 59 and a suggestion of reduced risk among women who started hormone therapy within 10 years after menopause.
Thereafter, the greater the gap between onset of menopause and start of hormone therapy, the greater the risk for heart disease, especially in those with a history of hot flashes and night sweats.
| 14 stories | 14 stories
The US slowdown has hurt the drugs industry and Hikma believes the market can't get much worse.
SURVEYS & REPORTS
Print this page
Email this to a friend
Discuss this article (0 Comments)
zoom
Mobile
