Introduction: In vitro studies indicate that vaspin may act as a regulator of bone metabolism. The aim of the study was to evaluate the relationship between vaspin and bone metabolism in girls with anorexia nervosa (AN), as well as the potential involvement of OPG and RANKL in this relationship.

Material and methods: Serum vaspin, OC, CTx, OPG, and sRANKL were determined by ELISA in 50 girls with AN and in 30 healthy controls aged 13 to 17 years.

Results: Girls with AN exhibited significant reduction in body weight, BMI, and Cole index as well as a significant increase in serum level of vaspin compared to healthy participants. These changes were associated with a significant decrease in serum OC and CTx levels and a significant increase in OPG and sRANKL, while the OPG/sRANKL ratio was significantly decreased. BMI and Cole index correlated negatively and significantly with CTx levels in the control group (C), girls with AN, and all study participants (C+AN). Girls with AN showed a significant negative correlation between BMI, the Cole index, and OPG levels. The combination group (C+AN) showed a significant positive correlation between BMI, Cole index, and the OPG/sRANKL ratio. In this group of girls vaspin levels correlated positively and significantly with sRANKL and negatively with body weight, BMI, Cole index, and OPG/sRANKL ratio. Girls with AN showed a significant negative correlation between vaspin levels and the OPG/sRANKL ratio.

Conclusions: Undernourishment and associated deficit of adipose tissue may result in inadequate vaspin production and bone metabolism disorders in girls with AN. Vaspin acts as a coordinator of the dynamic balance between bone formation and resorption processes; its action is affected by the cytokines of the RANKL/RANK/OPG system. Changes in the relationships between vaspin, bone markers, OPG, and RANKL might contribute to the development of osteoporosis in girls with AN. (Endokrynol Pol 2016; 67 (6): 599–606)