Estrogen replacement therapy 1: a 10-year prospective study in the relationship to osteoporosis.

Osteoporosis is the most common chronic skeletal disorder in which the total skeletal mass is decreased but the shape composition and morphology of the bones are normal; it increases bone fragility which leads to fractures. Albright (1941) and other recent reports indicated an etiological association between menopause and osteoporosis. Since estrogen is one of the many agents involved in bone physiology a 10-year study was conducted to investigate the relationship between estrogen replacement therapy (ERT) and osteoporosis using 84 matched pairs of women (according to age < 45 years and disease). Daily doses of 2.5 mg. conjugated estrogen tablets plus 10 mg. daily of medroxyprogesterone acetate tablets for 7 days of each month were given to the treatment group while the control group received placebo physically similar to the active medication. All patients showed a high incidence of osteoporosis (40%) compared to the normal population (25-35%). The number of years since the last menstrual period (LMP) significantly influenced response to treatment with the active medication (p=.001). The placebo-treated group lost bone mass during the study period while the estrogen treated groups either gained mass (when treatment was begun within 3 years of LMP) or had minimal bone loss. 7 fractures were observed in the control group and none in the treated group. At the end of 10 years there were no new cases of osteoporosis among the treated patients while 6 new cases were observed among the controls. These findings suggest that ERT could effectively reduce loss of bone mass associated with the postmenopausal state especially when administered within 3 years of LMP; it also confirmed David et. al.s report concerning estrogen and aging.