Effects of growth hormone treatment in juvenile idiopathic arthritis: bone and body composition.

Background: Inflammation and glucocorticoid therapy are major factors influencing growth and bone maturation in patients with juvenile idiopathic arthritis (JIA). In addition to alterations in total bone mineral density and bone geometry, longitudinal data confirm that the main contributors to errant bone maturation in patients with JIA are reductions in muscle mass and force. Growth hormone (GH) therapy, which has shown efficacy in controlling disease, may also positively influence body composition. For several years, GH therapy has been used to treat growth retardation in patients with JIA receiving glucocorticoids. GH therapy normalizes growth velocity, increases height, bone mineral density and bone mass and changes bone geometry. Despite ongoing glucocorticoid therapy, muscle mass and bone size substantially increase with GH therapy. Increased bone size suggests improved bone stability, which may reduce fracture risk. Along with the increase in muscle mass, patients experience stabilized or slightly decreased fat mass during GH therapy.

Conclusions: All these effects suggest an anabolic effect of GH therapy on bone and body composition.