Increased loss of trabecular but not cortical bone density, 1 year after discontinuation of 2 years hormone replacement therapy with Tibolone

Objective: Assessment of loss of bone density (BD) 1 year after a 2-year pe riod of hormone replacement therapy (HRT) with two doses of Tibolone as com pared to placebo in early post-menopausal women. Methods: Sixty-four out of 84 women (1-3 years following spontaneous menopause) who completed a 2-yea r randomised, placebo controlled study to evaluate effects of Tibolone part icipated in this follow-up study. Quantitative computed tomography was used to exclusively measure trabecular BD, microdensitometry of the mid-phalang eal shaft was used for estimation of cortical ED and biochemical markers of bone metabolism were assessed, 1 year after discontinuation of Tibolone. T he study group received either placebo (n = 16), 1.25 mg/day Tibolone (n = 25) or 2.5 mg/day Tibolone (n = 23). Results: Observations revealed a signi ficantly greater decrease in trabecular ED during the post-trial year in bo th treatment groups compared to the placebo group (for 1.25 mg/day Tibolone , -6.0%, 95% CI -8.4 to -3.5; for 2.5 mg/day Tibolone, -10.0%, 95% CI -12.9 to -6.9). In contrast, there was no significant difference in loss of phal angeal ED in both treatment groups compared to placebo. Biochemical markers (serum alkaline phosphatase, urinary excretion of hydroxyproline and calci um) do not suggest an increased bone turnover comparing Tibolone groups to placebo, 1 year after cessation of Tibolone. Conclusion: The present study suggests an increased loss of trabecular but not cortical ED as compared to the placebo group in the first year after cessation of HRT with Tibolone i n early post-menopausal women. (C) 1999 Elsevier Science Ireland Ltd. All r ights reserved.