The role of serum osteoprotegerin and receptor–activator of nuclear factor-κB ligand in metabolic bone disease of women after obesity surgery

Metabolic bone disease may appear as a complication of obesity surgery. Because an imbalance in the osteoprotegerin and receptor–activator of nuclear factor-κB ligand system may underlie osteoporosis, we aimed to study this system in humans in the metabolic bone disease occurring after obesity surgery. In this study we included s ixty women with a mean age of 47 ± 10 years studied 7 ± 2 years after bariatric surgery. The variables studied were bone mineral density, β-isomer of C-terminal telopeptide of type I collagen cross-links (a bone resorption marker), the bone formation markers osteocalcin and N-terminal propeptide of procollagen 1, serum osteoprotegerin and receptor–activator of nuclear factor-κB ligand. Serum osteoprotegerin inversely correlated with the bone remodeling markers osteocalcin, β-isomer of C-terminal telopeptide of type I collagen cross-links and N-terminal propeptide of procollagen 1. The osteoprotegerin and receptor–activator of nuclear factor-κB ligand ratio also correlated inversely with serum parathormone and osteocalcin. Bone mineral density at the lumbar spine was associated with age ( β = −0.235, P = 0.046), percentage of weight loss ( β = 0.421, P = 0.001) and osteoprotegerin and receptor–activator of nuclear factor-κB ligand ratio ( β = 0.259, P = 0.029) in stepwise multivariate analysis ( R 2 = 0.29, F = 7.49, P