Objectives: An analysis was performed to determine the risks and benefits of a 10-year hormone replacement therapy regimen that had been applied to all women at 50 years of age in 8 countries.
Methods: Cumulative mortality with and without hormone replacement therapy over 20 years was estimated, with both current and predicted total and disease-specific secular mortality trends and the influence of a generational cohort effect taken into account.
Results: In countries with high ischemic heart disease frequency and predictable relative predominance of ischemic heart disease rates over breast cancer rates for the next 20 years, hormone replacement therapy could result in benefits with regard to overall mortality; this advantage decreases in younger-generation cohorts. In countries in which breast cancer mortality predominates over ischemic heart disease in early postmenopause and in which the predictable trends for both diseases reinforce this condition, a negative effect on overall mortality would be observed. In the United States, the effect of large-scale hormone replacement therapy would change over time.
Conclusions: The long-term effect of hormone replacement therapy on life expectancy of postmenopausal women may vary among countries.