COMPARATIVE EFFECTS ON BONE-MINERAL DENSITY OF TIBOLONE, TRANSDERMAL ESTROGEN AND ORAL ESTROGEN PROGESTOGEN THERAPY IN POSTMENOPAUSAL WOMEN/

The aim of the study was to assess the comparative effects on bone min eral density (BMD) in routine clinical practice of tibolone and estrog en (given either unopposed or combined with cyclical progestogen) in p ostmenopausal women who had not previously received estrogen or other menopausal therapy. BMD was measured in the spine and hip by dual ener gy X-ray absorptiometry (DEXA) at 12-month intervals over 3 years in 8 2 consecutive postmenopausal women referred for climacteric therapy. O f these, 35 women received tibolone, 24 transdermal estradiol alone an d 12 conjugated equine estrogens together with cyclical progestogen; 1 1 received no therapy other than calcium. BMD increased significantly in the spine in those taking tibolone over 3 years (p <0.0001 at 1 yea r; p <0.0001 at 2 years; and p=0.03 at 3 years). In those treated with conjugated equine estrogens and cyclical progestogen, BMD in the spin e also increased significantly over the first 2 years (p=0.03 at 1 yea r; p=0.004 at 2 years), but not at 3 years. However, although BMD in t he spine also rose over 3 years in the women, treated with transdermal estradiol alone the increase was not statistically significant. No si gnificant change in the BMD of either the spine or the hip was observe d in the control group. A significant difference in the increase of BM D in the spine between the different treatment groups was observed at 2 years (p=0.004) in favor of those taking tibolone or conjugated equi ne estrogens, compared to women who received transdermal estradiol. Th e highest proportion of individual responders to therapy after 2 years ' treatment was observed in those receiving tibolone or conjugated equ ine estrogens. There was no significant change in the BMD of the hip o ver 3 years, irrespective of the therapy taken, although there was a t endency towards a progressive increase in the women on tibolone. Neith er the age of the women, their body mass index or pretreatment BMD had a significant effect on changes in bone density. Since tibolone effec ted a greater increase in spine BMD than did either conjugated equine estrogen with progestogen or transdermal estradiol alone, it is partic ularly suitable for older women who often have more advanced osteoporo sis and who would not accept a return of cyclical bleeding.