MAGNITUDE AND PATTERN OF SKELETAL RESPONSE TO LONG-TERM CONTINUOUS AND CYCLIC SEQUENTIAL OESTROGEN PROGESTIN TREATMENT/

Objective To investigate the magnitude and pattern of the changes in b one mass during five years of continuous and cyclic sequential oestrog en/progestin treatment. Design Prospective study of normal, early post menopausal women, initially a double-blind, placebo controlled trial, subsequently an open, controlled investigation. Setting Clinical physi ology unit of a general hospital. Subjects Sixty-eight normal, early p ostmenopausal women. Results 1. Continuous treatment resulted in signi ficantly higher lumbar spine bone density than did sequential treatmen t (P < 0.001). Lumbar spine bone density was 19% and 15%, respectively , above that of untreated women after three years and onwards, and 10% and 6%, respectively, above the initial value; 2. Both regimens induc ed a more pronounced rise in lumbar spine bone density than in forearm bone mineral content (P < 0.001); 3. The spontaneous decline (without treatment) in lumbar spine bone density and forearm bone mineral cont ent averaged 1.86% and 1.90% per year, respectively. 4. There was a si gnificant bone loss from the lumbar spine during the last year of acti ve treatment (P < 0.001). This would suggest that lumbar spine bone de nsity rises to a certain level and subsequently declines. However, nei ther data pooled before computation nor data processed individually fo r each patient over five years allowed for any definite conclusions re garding the pattern of the long term skeletal response to combined oes trogen/progestin treatment. Conclusion Five years treatment with oestr adiol/norethisterone resulted in a substantial gain in bone mass. The highest values were found in the axial skeleton with daily administrat ion of 2 mg oestradiol and 1 mg norethisterone. It is likely that bone mass after an absolute rise begins to decline after about four years of treatment.