Aim: Thyroid hormones play an important role in bone remodeling. The aim of the study was to evaluate the changes of bone markers and osteoprotegerin (OPG)/sRANK-L levels during follow-up in a group of patients with thyroid cancer.
Material and methods: Twenty euthyroid women with the diagnosis of differentiated thyroid cancer were enrolled to the study (39.25±13.46 years, 6 postmenopausal) before thyroidectomy. Samples were collected before the operation (euthyroid status) (EU), before radioactive iodine administration (hypothyroidism) (HYPO) and under thyroxine supressive therapy (subclinical hyperthyroidism) (SHYPER). In addition to OPG and sRANK-L, the markers of bone formation (BALP, osteocalcin and P1NP) and resorption (urinary DPD) were also evaluated. To determine the independent effect of bone formation markers and TSH on OPG, a multiple logistic regression model was used after pooling all the 3 visits data. Statistical analysis were performed on SPSS 15.0.
Results: The level of all bone formation markers except urinary DPD decreased in HYPO when compared to EU period (P=0.047 for BALP, P=0.003 for osteocalcin, P=0.024 for P1NP). However no significant change was observed in urinary DPD. In SHYPER period all of the bone formation markers increased and reached to the levels of EU period. OPG levels increased in HYPO period (P<0.001) and returned to comparable levels in SHYPER period. RANK-L levels did not change during the 3 different periods of the study. In multiple regression analysis, the only significant variable was TSH (r2=0.446, P=0.001).
Conclusion: In this study, we tried to investigate the relationship of thyroid dysfunction and skeletal system. The results indicate that there is a decrease in bone formation and an increase in OPG levels in HYPO but no change in SHYPER period. The increase in OPG level was related to increase in TSH but not to any of the bone formation markers.
25 - 29 Apr 2009
European Society of Endocrinology