Serum1,25dihydroxyvitamin D andosteocalcin concentrations inthalassaemia major

SUMMARY In view of the claim that low 25-hydroxyvitamin D(25-OHD) concentrations may contribute to the pathogenesis of bone disease in patients with 13 thalassaemia major and ironoverload, we have assessed the concentrations of 25-OHD, la,25 dihydroxyvitamin D(la,25(0H)2D), parathyroid hormone, and osteocalcin in such patients. 25-OHD concentra- tions were significantly lower in patients with thalassaemia major and iron overload than incontrols and in some patients were subnormal or undectectable. la,25(OH)2D concentrations were, however, normal in all patients and were similar to those in controls. Serumparathyroidhormone and plasma calcium concentrations were also normal and not significantly differentfrom those in controls. Although 25-OHD concentrations increased significantly betweenJanuary and June, there was no change in la,25(OH)2D concentrations. 25-OHD concentra- tionsremainedlowerthancontrolvalues, even in June. Parathyroidhormoneconcentrationsfell,but not significantly, between January and June, but calcium concentrations did