The effect of tibolone on fat mass, fat-free mass, and total body water in postmenopausal women.

Changes in body composition occur around the menopausal transition. The major characteristics are a decline in fat-free mass and an increase in body fat as a percentage of body weight. These alterations might be affected by age only or by menopause-related changes in hormone concentration. In this study the effects of tibolone, a tissue-specific compound with favorable effects on bone, vagina, and climacteric symptoms, were determined on body composition using bioelectrical impedance analysis. The focus was especially on fat mass, fat-free mass, and total body water in a group of 85 healthy women (mean +/- SD age, 54.2 +/- 4.7 yr), between 1-15 yr postmenopausal. Participants were randomly assigned to either tibolone (2.5 mg; n = 42) or identically appearing placebo tablets (n = 43) daily for 12 months. All analyses were based on the intent to treat group and last visit. Compared with placebo, tibolone significantly increased fat-free mass by 0.85 kg (P = 0.003) and total body water by 0.78 liter (P = 0.001). No significant difference was observed on the fat mass parameter (P = 0.16). From these results it can be concluded that tibolone may counteract the postmenopausal changes in body composition.