Long-Term Effects of Oral Progesterone (Medroxyprogesterone Acetate) on the Level of Bone Mineral Density During Estrogen Replacement Therapy in Postmenopausal Women

Kim, Su Ryun; Park, Gyo Man; Jung, Eul Young; Min, Chang Soo; Shin, Yong Duk; Jin, Keon; Kim, Dong Jin

Abstract

Estrogen replacement therapy is known to reduce the incidence of cardiovascular disease and osteoporosis in postmenopausal women. Estrogen has beneficial effect on bone density and adding progesterone to estrogen is known to have synergistic effect. However, the effect of progesterone on bone mineral density had not been precisely evaluated in Korean postmenopausal women. To evaluate the impacts of progesterone on bone mineral density during estrogen replacement therapy, we conducted the randomized 2-year trials of conjugated equine estrogen (Premarin(R) 0.625 mg/day) with or without cyclic progesterone(medroxyprogesterone acetate : MPA 10 mg/day for 12 days) in 105 postmenopausal women. Bone mineral density was measured in the lumbar vertebrae(L2-L4) using dual energy X-ray absorptiometry(DEXA) at the beginning of the treatment, 6 onths, 12 months and 24 months later, respectively. In Premarin only group, bone mineral density at 6 months and 12 months after treatment did not show significant difference from baseline value. But bone mineral density on 24 months after treatment showed significantly increased value(p value<0.05) than that of initial. In Premarin plus MPA group, bone mineral density at 12 months and 24 months after treatment showed significantly increased than baseline(p value<0.05). And compared with Premarin only group, Premarin plus MPA group showed significant increase in spinal bone density after 2 years treatment(p value<0.05). These results suggest that the addition of MPA in estrogen replacement therapy appears to increase in bone mineral density more than unopposed estrogen. Thus combination of estrogen and progesterone appeared to be effective long-term prophylactic treatment regimen upon postmenopausal bone loss.