BOSTON, Jan. 24 - Whether postmenopausal hormone therapy, if taken to relieve symptoms, affects a woman's risk for coronary heart disease may depend on the timing of therapy, an analysis of the Nurses' Health Study suggested.
Indeed, women who began therapy within four years of menopause had about 30% lower risk of heart disease than did women who never used hormones, said Francine Grodstein, Sc.D., and colleagues at Brigham and Women's Hospital here.
However, when therapy was initiated 10 or more years after menopause there was no significant association with coronary heart disease, the researchers reported in the January issue of the Journal of Women's Health.
The study authors cautioned that their results do not support hormone therapy for prevention of coronary heart disease. "The clear risks of postmenopausal hormones (e.g., increases in stroke, pulmonary embolism, and possibly breast cancer) in both randomized trials and observational studies rule out a general indication for their long-term use in chronic disease prevention," they concluded.
Previous studies of postmenopausal HRT have yielded conflicting results, with some studies suggesting an increased risk of heart disease associated with hormone therapy, the researchers said. The current study explored the effects of initiating therapy at varying intervals since menopause and at different ages.
The researchers analyzed data from the Nurses' Health Study. Started in 1976, this study included more than 121,000 female nurses age 30 to 55. The current study followed this cohort through June 1, 2000. Key findings include the following:
* Women beginning therapy within four years of menopause had a significantly reduced risk of coronary heart disease (relative risk=0.66; 95% confidence interval=0.54-0.80 for estrogen alone; RR =0.72; 95% CI=0.56-0.92 for estrogen with progestin).
* Among women who initiated therapy at least 10 years after menopause, the study found no significant association (RR=0.87; 95% CI=0.69-1.10 for estrogen alone; RR =0.90; 95% CI=0.62-1.29 for estrogen with progestin).
* Among women who began taking hormones at age 60 or older, the study found no relation between estrogen alone and coronary heart disease (RR=1.07; 95% CI=0.65-1.78), although there was a non-significant suggestion of possible reduced risk for estrogen with progestin (RR =0.65, 95% CI=0.31-1.38).
The investigators examined the medical records of postmenopausal nurses who experienced a non-fatal myocardial infarction or who died from coronary disease during the study period to see if and when they underwent hormone therapy.
"This study helps to untangle some of the confusion about the heart-protective effects of hormone therapy by indicating that the timing of starting hormones relative to a woman's age and onset of menopause plays a key role," said Joann E. Manson, M.D., Dr.P.H., also of Brigham and Women's Hospital, a co-author.