The design of the hormone therapy trial (HT) was approached with the hypothesis that estrogen therapy would result in a decrease in coronary heart disease and osteoporosis-related fractures. As such, the primary outcome of interest was coronary heart disease, as this is a major cause of morbidity and mortality among women, particularly those over age 65, and because, at the time, no clinical trial had been undertaken to prove the cardioprotective effects of HT. Due to the concern over the relationship between HT and elevated breast cancer risk, breast cancer was selected as the primary adverse outcome. Additional outcomes monitored included stroke, pulmonary embolism (PE), endometrial cancer, colorectal cancer, hip fracture, and death due to other causes.