OPAL – Osteoporosis Prevention and Arterial Effects of Tibolone Study
Principal contacts
Michiel L. Bots - University Medical Center Utrecht, Utrecht, the Netherlands
Frans A. Helmond - Merck Research Laboratories, Kenilworth, NJ, USA
Study design
The Osteoporosis Prevention and Arterial Effects of Tibolone Study (OPAL) is a three-arm clinical trial based in six US centres (Minneapolis, San Diego [2x], Portland, Chicago, Charlotte), and five European centres (United Kingdom, Germany, the Netherlands [2×], Sweden). The principal aim of the trial was to investigate the effect of Tibolone (2.5mg/day) versus Estrogens (0,625mg/day) and Progesterone (2.5mg/day) versus placebo on the progression of carotid intima-media thickness and bone mineral density of the lumbar vertebrae and proximal femur in postmenopausal women. Healthy postmenopausal women were eligible for inclusion if they were aged between 45 and 79. Approval was obtained from the institutional review boards of the participating clinics and written informed consent was obtained from all study participants.
Key publications
The Osteoporosis Prevention and Arterial effects of tiboLone (OPAL) study: design and baseline characteristics. Control Clin Trials. 2003 Dec;24(6):752-75
The effect of tibolone and continuous combined conjugated equine oestrogens plus medroxyprogesterone acetate on progression of carotid intima–media thickness: the Osteoporosis Prevention and Arterial effects of tiboLone (OPAL) study. Eur Heart J. 2006 Mar;27(6):746-55
Ultrasound protocols to measure carotid intima–media thickness: a post-hoc analysis of the OPAL study. Curr Med Res Opin. 2009 Jan;25(1):109-22