In 1995 researchers at the Harvard Medical School reported that
hormone replacement therapy (HRT) increased the risk of breast cancer in postmenopausal
women. The fact that unopposed estrogen therapy increases the risk of breast cancer had been reported in
1992. Shortly thereafter a large clinical trial was begun to see if estrogen/progestin therapy (HRT) would be
of benefit to postmenopausal women with heart disease. This trial, the Heart and Estrogen/Progestin
Replacement Study (HERS), involved 2763 postmenopausal women with documented coronary heart
disease. Half the participants (1380 women) were assigned to receive 0.625 mg of conjugated estrogens
plus 2.5 mg of medroxyprogesterone acetate daily; the other half (1382 women) received a placebo. After
4.1 years of follow-up there was no indication that HRT was of any overall benefit in preventing non-fatal
heart attacks or death from heart disease. It did appear that HRT users had more cardiac events than the
placebo users in the first year, but this was compensated for by fewer events in years three to five.
The HERS study was continued in a slightly modified form (HERS II) for another 2.7 years. At the end of the
total 6.8 years of follow-up the conclusions were:
- HRT does not reduce the risk of cardiovascular events in postmenopausal women with heart disease;
- HRT doubles the risk of blood clots (venous thromboembolism);
- HRT increases the risk of gallstones and subsequent gallbladder (biliary tract) surgery by 50 per cent.
There was a slight, but statistically non-significant increase in cancer incidence among HRT users. Breast
cancer rates were 27 per cent higher in the HRT group and lung cancer incidence was 39 per cent higher.
Women who used HRT also tended to have more hip fractures. The researchers conclude that HRT does
not reduce cardiovascular events in women with heart disease and increases the risk of blood clots,
gallstones, and hip fractures.
A larger trial involving 27,348 healthy women on HRT has just concluded that HRT increases the risk of
blood clots, stroke and heart attacks in these women and may increase the risk of breast cancer. NOTE:
This study was funded by Wyeth-Ayerst Research, a pharmaceutical company.
Grady, Deborah, et al. Cardiovascular disease outcomes during 6.8 years of hormone therapy. Journal of
the American Medical Association, Vol. 288, July 3, 2002, pp. 49-57
Hulley, Stephen, et al. Noncardiovascular disease outcomes during 6.8 years of hormone therapy. Journal
of the American Medical Association, Vol. 288, July 3, 2002, pp. 58-66
Petitti, Diana B. Hormone replacement therapy for prevention. Journal of the American Medical
Association, Vol. 288, July 3, 2002, pp. 99-101
Tanne, Janice Hopkins. Hormone trial for disease prevention stopped early. British Medical Journal, Vol.
325, July 13, 2002, p. 61
Editor's comment: There has been some hope that HRT may help prevent Alzheimer's disease. A
recent study, however, demolished this notion. It is now clear that HRT has no health benefits – quite the
contrary – and that there is no medical justification for prescribing it.