Sickle cell bone disease: Response to vitamin D and calcium

Abstract

Bone disease with osteoporosis and osteomalacia are common in sickle cell disease (SCD). Some patients have vitamin D deficiency and low bone mineral density (BMD). The role of vitamin D and calcium supplementation to restore bone health in SCD has not been well studied. In 14 adults with SCD, we measured 25(OH)D (25-hydroxyvitamin D) and BMD at the femoral neck, lumbar spine, and distal third of the ulna plus radius, along with markers of bone resorption (CTx; C-terminal component of pro-collagen type I) and bone formation (osteocalcin) before and after 12 months of vitamin D2 and calcium carbonate treatment. Pretreatment, all patients were vitamin D deficient with a mean 25(OH)D level of 10.7 ± 4.7 ng/ml, had low BMD at the lumbar spine (L-spine), 0.87 ± 0.11 g/cm2 (mean Z-score of -2.6 3 ± 0.71 SD and T score of -2.31 ± 0.75 SD), femoral neck, 0.8 ± 0.18 g/cm2 (mean Z-score -1.36 ± 0.84, T-score -1.14 ± 0.75), and the distal radius and ulna, 0.6 ± 0.17 g/cm2 (mean Z-score -1.18 ± 0.79, T-score -1.01 ± 0.74) and had elevated CTx (0.87 ± 0.5 ng/ml) and osteocalcin levels (12.3 ± 3.7 ng/μL). After treatment, all patients corrected their 25(OH)D level (38.8 ± 13.9 ng/ml) (P < 0.001) with a 3.6% ± 3.9% increase in BMD at the L-spine (P = 0.009), 4.6% ± 8.5% increase at the femoral neck (P = 0.05) and 6.5% ± 12.6% increase at the distal radius plus ulna (P = 0.09). CTx, osteocalcin, and PTH(i) levels were unchanged. Treatment of adult SCD with vitamin D and calcium can restore 25(OH)D levels to normal and improve BMD, but, markers of bone resorption remained unchanged. Screening for vitamin D deficiency and BMD in SCD patients seems warranted. © 2007 Wiley-Liss, Inc.