CYP27A1 and anorexia nervosa: Moreover, Gołąbek et al. and Guo et al. found significant negative correlations between serum omentin-1 and BMD at the LS and TH as well as bone formation (BAP, osteocalcin (OC), the OC/C-terminal telopeptide fragments of type I collagen (CTX), and osteoprotegerin (OPG)/soluble receptor activator of nuclear factor-κB ligand (sRANKL) ratios) and resorption markers (CTX and NTX) in girls with anorexia nervosa [11, 14, 26].