Long-Term Vitamin D Supplementation Improves Bone Mineral Density (BMD) in Patients with Sickle Cell Disease.

Adewoye, Adeboye H.; Holick, Michael F.; McMahon, Lillian C.; Ma, Qanli; Steinberg, Martin H.

doi:10.1182/blood.V108.11.3800.3800

Abstract

Among the many complications of sickle cell disease (SCD) are osteopenia and osteoporosis. We and others have previously documented a high prevalence of low serum 25-OH vitamin D level with accompanying osteopenia and osteoporosis in patients with SCD; however the long-term effects of treatment on BMD have not been reported. We hypothesized that supplementation with oral vitamin D and calcium will result in an improvement in BMD and accordingly, treated 6 adult subjects with SCD for 12 months with oral supplementation with vitamin D and calcium and studied the effects of treatment on BMD. Subjects with serum 25-OH D levels <20 ng/ml were placed on 50,000 IU of oral vitamin D weekly for 8 weeks, followed by 50,000 IU every other week for 44 weeks; subjects also received 1000 mg of elemental calcium daily. We evaluated BMD at weeks 1 and 52. Subjects had a mean pre-treatment plasma 25-OH vitamin D of 9.1 ng/ml. BMD was abnormal in all subjects; 4 subjects had osteoporosis with a Z-score <-2.5, and 2 subjects had osteopenia with a Z-score −1.9 to −2.5 (in the lumbo-sacral vertebrae). All subjects had mildly elevated intact PTH levels which were within the reference range but declined further post-treatment. Following one year of treatment with vitamin D and calcium, we observed a mean post-treatment increase in BMD of 5.4% (p value <0.02) and a 176% increase in plasma 25-OH D level (from 9.1ng/ml to 28ng/ml; p value <0.009). All patients with SCD we have studied have hypovitaminosis D that in adults is associated with low BMD. In patients followed for one year who received supplementation with calcium and vitamin D, 25-OH D level increased in all and BMD improved in four of six subjects. These results suggest that this treatment regimen can be effective is restoring BMD. The reasons for apparent unresponsiveness in some patients must be further evaluated. Clinical trials to document the effectiveness of treatment for this ubiquitous problem should be instituted.