Elevated soluble receptor activator of nuclear factor-kappaB ligand and reduced bone mineral density in patients with adolescent idiopathic scoliosis.

Generalized low bone mass and osteopenia in both axial and peripheral skeleton in adolescent idiopathic scoliosis (AIS) have been reported in literature. However, the exact mechanisms and causes of the bone loss in AIS are not identified yet. Therefore, this study examined the relationship between serum concentration of soluble receptor activator of nuclear factor-kappaB ligand (RANKL), serum level of osteoprotegerin (OPG) and bone mass in 72 patients with AIS and compared to those of 64 age- and gender-matched healthy controls. The mean lumbar spinal bone mineral density (LSBMD) and femoral neck BMD (FNBMD) in patients with AIS were decreased compared with that in control individuals, respectively (P = 0.0029 and P = 0.0192, respectively). The mean RANKL and RANKL to OPG ratio in patients with AIS were increased compared with that in control subjects, respectively (P = 0.0004 and P = 0.0032, respectively). The RANKL and RANKL to OPG ratios were negatively correlated to the LSBMD and serum OPG levels in both groups. Serum OPG levels were positively correlated to the LSBMD and FNBMD in both groups. These findings mean that the imbalance and the disturbed interaction of RANKL and OPG may be an important cause and pathogenesis in reduced BMD in AIS.