Endocrine Abstracts

Objectives: To characterize the possible role of the osteoprotegerin (OPG) and receptor activator of NF-κB ligand (RANKL) system in thalassemia-related bone loss.

Background: Osteoporosis represents an important cause of morbidity in patients with β-thalassemia major and its aetiology is multifactorial.

Methods: Serum concentrations of OPG, RANKL, markers of bone turnover and lumbar spine bone mineral density (BMD) were measured in random samples of males (n=31, mean age 24.4 years, range 13–41) and females (n=35, mean age 24.3 years, range 12–35) with β-thalassemia major.

Results: There was a significant difference between males and females concerning ferritin levels (1873±214 ng/ml vs. 3384±346 ng/ml, respectively, P< 0.05) and RANKL levels (0.5±0.077 pmol/l vs 0.21±0.042 pmol/l, P<0.05). Age correlated positively with OPG/RANKL ratio (r=0.38, P<0.05) and negatively with RANKL (r=−0.3, P<0.05). Moreover, osteoprotegerin positively correlated with the duration of the interval between the onset of transfusions and chelation therapy (r=0.26, P<0.05). Regarding markers of bone metabolism, plasma values ofosteocalcin (OC) correlated positively with RANKL (r=0.43, P>0.05) and negatively with OPG/RANKL ratio (r=−0.47, P<0.05). RANKL correlated negatively with age (r=−0.68, P<0.001) and ferritin (r=−0.60, P<0.001) while OPG correlated positively with ferritin (r=0.36, P<0.05).

Conclusions: Although OPG/RANKL system may have some clinical usefulness as a marker of bone turnover in β-thalassemia, only NTX significantly accounted for BMD in multiple regression analysis.