Objectives: To observe the effectiveness and safety of menopause-related hormone therapy (MHT) to prevent bone loss in Chinese women during the menopausal transition and early menopause, as well as to evaluate the effects of 5-year MHT on overall health to add Level I evidence for the prevention of osteoporosis using MHT.Design: This clinical study was a prospective, double-blind, randomized, parallel placebo-controlled study. Chinese women in the menopausal transition and early menopause were randomly allocated to the MHT group or the placebo group. All subjects received a 5-year intervention. The effectiveness of MHT for bone mineral density (BMD) and bone metabolism and the safety of MHT in relation to glycolipid metabolism, breast cancer, and cardiovascular disease were studied.Results: In the MHT group, women in both transition and early menopause showed a significant increase in lumbar and femoral neck BMD after the 1st year of therapy; BMD tended to decrease in the 3rd year but ultimately was sustained at stable levels that were near the baseline levels. In the placebo group, BMD decreased at both sites. Metabolism indexes and breast ultrasound examination findings did not differ significantly between the MHT and placebo groups. Three cases of breast cancer and three cases of cardiovascular disease were diagnosed during follow-up. One breast cancer case and two cardiovascular disease cases occurred in the MHT group.Conclusions: Five-year sequential therapy with estrogen and progesterone can increase or maintain the BMD of women in their menopausal transition and early menopause. This regimen had no negative effect on glycolipid metabolism and did not increase the risk of breast cancer or cardiovascular events.