Osteoporosis is the direct effect of the loss of bone density.
Bone mineral density in the hip increased by 1.7 percent in the treatment groups compared to a 1.7 percent decline in the control group. PEPI compared the effect of oral estrogen alone and combinations of estrogen and one of three progestin regimens with an inert placebo. PEPI is the largest and longest clinical trial to examine this issue. PEPI confirmed that estrogen protects against bone loss, but did not study the rate of fractures. Combined with PEPI's earlier findings on heart disease risk factors a nd on endometrial changes, this study is one of the best current sources of information on the risks and benefits of hormone replacement therapy.