P. Eiken, N. Kolthoff, S. Pors Nielsen
EFFECTS OF WITHDRAWAL OF HAT wITH TZBOLON~ON Bo~rR MINERAL DENSITY IN EARLY POBTMZNOPAUSJ~L WOMEN Berninu B(1), Kuyok van C(2), Kioovio PM(3), Coelingh Bennink HJT(3), Fauser BCJM(2). (1)Dept 0bs/Gyn; (2)Dept Radiol, DiJkzlgt University Hospital, Rotterdam, The Netherlands; (3) MRDU, NVOrganon, Oss, The Netherlands. PURPOSE= To quantify the loss of BDM after HRT with two doses of tibolone 1.25 mg/d(A) (nffi25) and 2.5 mg/d(B) (n=23) as compared to placebo(C) (nffil6). METHODS= 94 postmenopausal women, participated in a 2 year randomized, placebo controlled study to evaluate the effect of tibolone on trabecular and cortical BMD. 64 volunteered for an assessment of BMD one year after completing the study. Trabecular BMD of the spinewas measured with Quantitative Computed Tomography, cortical BMD was estimated by Quantitative Microdensitometry of the mid-phalanx. Change of BMDwas expressed as the mean percent change from baseline. RESULTS= During the study trabecular EMD changed in group A, B and C (3.2%, 9.3% and -6.7%, resp.). Loss of trabeeular BMD in the post-trial year for group A, B and c was -7.0%, -12.1% and -2.6%, resp. This loss was significantly different between all groups (p<0.001}. During the study cortical BMD changed in group A, B and C (4.6%, 5.5% and -1.4%, resp.). Loss of cortical END in the post-trial year for group A, B and C was 2.6%, ,2.4% and -2.4%, resp., which was not significantly different from each ether. 9ONCLUBION= In contrast to cortical BMD, there is an increased loss of trabecular BMD in the first year after HRTwith tibolone. These data suggest that long-term HRT with tibolone is needed for prevention of osteoporosis, similar to estrogens.