Bone mineral content and bone mineral metabolism: Changes after growth hormone treatment in juvenile chronic arthritis

Objective. To determine whether growth, hormone (rhGH) affects bone mineral metabolism and bone mineral content (BMC, g/cm) in a therapeutic trial of recombinant growth hormone in growth retarded children with juvenile chroni c arthritis (JCA) treated with steroid. Methods. BMC was measured in 20 children (of whom 17 were treated with cort icosteroid) before and after one year of rhGH. Children were randomized to receive either low dose (12 IU/m(2)/week) or high dose (24 IU/m(2)/week) fo r one year. Three monthly assessments were made of disease activity and ant hropomorphic measurements. Blood and urine samples were also obtained to me asure indicators of disease activity, bone remodeling, and vitamin D and pa rathyroid hormone (PTH) status. Results. BMC increased during the treatment period and correlated with incr easing height. Osteocalcin levels, normally indicators of bone formation, i ncreased after rhGH treatment and correlated significantly with height velo city, particularly for the high dose treatment group. In contrast, osteocal cin levels were negatively correlated with C-reactive protein levels, both before and during treatment. Height velocity, vitamin D, PTH, and osteocalc in levels were significantly lower than age matched controls before treatme nt. Conclusion. Steroid treated children with both JCA and severe growth retard ation have reduced vitamin D, PTH, and osteocalcin levels. After treatment with rhGH, height velocity increased, as did BMC. Growth hormone might be a useful adjunct in the treatment of severe growth retardation and osteoporo sis in children with JCA. The longterm benefits of rhGH in the treatment of osteoporosis remain unclear.