Serum calcium and vitamin D status of patients with sickle cell disease in Curacao: comparison with Saudi Arabia

ABSTRACT

Data from Saudi Arabia suggest that low vitamin D status is involved in skeletal abnormalities of patients with homozygous sickle-cell disease (HbSS). We measured parameters of calcium homeostasis and vitamin D status in HbSS patients (median age 8 years, range 3-19; 8 females, 10 males) and matched HbAA controls living in the tropical island of Curacao. Serum calcium of HbSS patients (2.32 ñ 0.07 mmol/l) was lower (ANCOVA, p = 0.002) than that of HbAA controls (2.44 ñ 0.14). None of the subjects had hypocalcaemia. There were no differences in phosphate, total protein, albumin, intact parathyroid hormone (PTH), 25-hydroxyvitamin D [25(OH)D; HbSS 87 ñ 27, HbAA 86 ñ 15 nmol/l] and 1,25-dihydroxyvitamin D. There were no significant relationships between serum calcium and albumin, calcium and total protein, and PTH and 25 (OH)D. Our data suggest that hypocalcaemia and hyperparathyroidic tendencies in Saudi Arabian HbSS patients are likely to be caused by the locally poor vitamin D status, attributable to insufficient exposure to direct sunlight (AU)