Endocrine Abstracts

The aim of this study was to evaluate quantitative changes in OPG and RANKL proteins after tibolone and hormonal replacement therapy (HRT) administered to patients with oestrogen deficiency symptoms and osteopenia or postmenopausal osteoporosis.

Material and methods: A total of 74 women after menopause, aged 45–71 years, patients of the Outpatient Clinic of Osteoporosis of the Military Teaching Hospital in Lodz, were enrolled into the study. The patients were randomly assigned to different medical therapies: HRT and tibolone. Patients of the control group received only calcium and vitamin D₃ supplements. Measurements of β-CTX (C-terminal Telopeptide of type 1 Collagene), osteocalcin, RANKL, OPG, alkaline phosphatase concentrations in serum (sALP), as well as total, 24 h calcium and phosphate levels in serum and urine were carried out in material collected at every visit (at baseline and after 3, 6 and 12 months of therapy). Densitometry of the left hip and the lumbar spine (LS) was done twice (at baseline visit and after 12 months).

Results: The observed changes in bone mineral density (BMD) between the groups, as well as within each group, were statistically insignificant. In none of the three groups were any significant differences in serum levels of the bone turnover markers, OPG and RANKL during the whole study period. A significant negative correlations were demonstrated between the differences in osteocalcin concentrations and BMD changes of LS, femoral neck and total tip in the tibolone receiving patients. Additionally, in the same group of patients, negative, statistically significant relationship was found between the alterations of β-CTX concentrations and the differences in LS BMD.

Conclusions: Both tibolone and HRT do not seem to cause any significant changes in OPG and RANKL protein serum levels during the first 12 months of treatment.