Serum calcium, parathyroid hormone, and vitamin D status in children and young adults with sickle cell disease.

The concentrations of serum calcium, parathyroid hormone (PTH), 25 Hydroxyvitamin D (25OHD), and 1,25 Dihydroxyvitamin D (1,25(OH)2D) were determined in 99 Saudi patients with sickle cell disease and in 104 matching healthy controls. Serum calcium and 25OHD were significantly lower in the patients, with 14% and 12% of them had serum calcium and 25OHD concentrations, respectively, below the normal range. PTH was significantly higher in the patients, with 31% having values above the normal range. There was no significant difference between patients and controls in regard to 1,25(OH)2D. There was a significant inverse correlation of 25OHD with PTH and a direct correlation of PTH with 1,25(OH)2D. Dietary intake of calcium and vitamin D was adequate in both patients and controls. The results indicate that sickle cell patients have hypocalcaemic tendency associated with supranormal PTH, and imply impaired intestinal absorption of calcium and vitamin D leading to a disturbed calcium metabolism which might contribute to the skeletal changes seen in sickle cell disease.