Biochemical versus radiological studies for early detection of steroid-induced bone depletion in children

ABSTRACT

To examine the early effects of the usual dose of prednisone treatment [1-2mg/kg / day] for about one month on bone depletion in different pediatric diseases. Bone mineral density [BMD] was measured using quantitative computed tomography [QCT]. Bone formation was quantified by measurement of serum osteocalcin, alkaline phosphatase, calcium and phosphorus. Bone resorption was measured by urinary excretion of calcium, phosphorus and hydroxyproline. BMD was significantly reduced in the steroid treated group [P < 0.05]. As regards bone formation parameters, only osteocalcin was significantly reduced [P < 0.05] while other parameters were not different. Urinary hydroxyproline and phosphorus as parameters of bone resorption were significantly elevated [P < 0.01 and < 0.05 respectively] with no change in urinary calcium excretion. No correlation has been found between BMD and any of the laboratory markers. One month treatment with prednisone in the usual dose is associated with some degree of bone depletion and although osteocalcin and hydroxyproline values were significantly different in the steroid treated group, yet they are weak substitutes for radiological studies [bone densitometry] in monitoring bone density in these patients