Hormone drugs may pose fewer risks for Chinese women

Hormone therapy originally taken to ward off chronic diseases may be linked to an increased risk of breast cancer in older Chinese women, but it does not seem to raise their risk of heart attacks or heart-related deaths, a new study suggests.

The findings expand upon the landmark Women's Health Initiative study of 2002, which found that a common estrogen-plus-progestin treatment increased a woman's risk for heart attacks, breast cancer and strokes.

"In our study, we found the same increased risk of breast cancer, but we didn't find an increased risk of heart disease," said Dr. Irene Su, an assistant professor of reproductive medicine at the University of California, San Diego, and the study's lead author.

The research suggests that the WHI findings on hormone therapy - derived largely from Caucasian women - may not apply across all racial and ethnic groups.

"Those risks and benefits may not be the same in Asian women as in white women," Su told Reuters Health. "You really can't assume it is going to be the same."

Some women take hormone pills containing estrogen and progestin or estrogen alone - marketed as Prempro or Premarin, respectively - to treat hot flashes and other symptoms of menopause.

Risks and benefits of menopausal hormone therapy in postmenopausal Chinese women

Objective: The aim of this study was to assess risks and benefits of conjugated equine estrogens (CEE) and medroxyprogesterone acetate (MPA) in postmenopausal Chinese women.

Methods: A retrospective cohort study was undertaken using the Taiwan National Health Insurance Research Database, a population-based healthcare claims dataset. Eligible women aged 50 to 79 years were classified as exposed to CEE 0.625 mg/day with MPA 5.0 mg/day (estrogen [E] + progestin [P], n = 4,712) or CEE 0.625 mg/day only (E-only, n = 1,208) and were age-matched to unexposed women (n = 10,125). Follow-up was complete in 96% of the participants. The primary outcomes were coronary heart disease (CHD) and invasive breast cancer. The global index summarized risks of primary outcomes, stroke, pulmonary embolism, colon and endometrial cancers, hip fractures, and death. Time-to-event analyses were performed.

Results: Median durations of exposure in the E + P and E-only groups were 6.9 and 9 months, respectively. Median follow-up was 110 months. Hazard ratios (95% CI) for E + P exposure were as follows: myocardial infarction, 0.78 (0.51-1.19); CHD death, 1.21 (0.53-2.70); breast cancer, 1.48 (1.20-1.83); global index, 0.79 (0.72-0.87). Hazard ratios for E-only exposure were as follows: myocardial infarction, 0.76 (0.35-1.68); CHD death, 0.57 (0.11-2.80); breast cancer, 1.44 (0.99-2.10); global index, 1.09 (0.92-1.28). Per 10,000 person-years, there were 12 excess breast cancer cases with E + P exposure; there were 39 fewer global index events with E + P exposure. Adjusting for age, statin and aspirin use, hypercholesterolemia, diabetes, and hypertension did not significantly change estimates.