25-hydroxy vitamin D deficiency following pediatric hematopoietic stem cell transplant.

Children may be at increased risk for vitamin D deficiency following HSCT because of lack of sun exposure, the recommended use of sunscreen, dietary insufficiency, malabsorption, and the use of certain medications. We prospectively assessed the prevalence of and risk factors for 25-hydroxy (25-OH) vitamin D deficiency in 67 patients transplanted at our institution. 25-OH vitamin D levels were checked during 3 separate 4-week periods in the spring, autumn, and winter. Subjects were <2 years following transplant and/or being treated for chronic graft-versus-host disease (cGVHD). Levels less than 20 ng/mL were considered deficient, and those less than 30 ng/mL were considered insufficient. The mean 25-OH vitamin D level was 22.8 ng/mL (range: 7-46.2). A total of 80.6% (confidence interval [CI] 69.1%-89.3%) of patients had a level less than the lower limit of the institutional normal range. The deficiency rate was 37.3% (CI 25.8%-50%). The mean parathyroid hormone (PTH) level was 77.5 (SD = 80.5). There was no correlation between 25-OH vitamin D and PTH levels. We evaluated potential risk factors for 25-OH vitamin D deficiency including age, season of testing, sun exposure, sunscreen use, use of steroid or calcineurin inhibitor, race, and dairy intake. In multivariate logistic regression, only older age was found to be a risk factor for deficiency (P = .004). Patients with deficient levels were treated with 50,000 IU of ergocalciferol once weekly for 6 weeks. A postrepletion 25-OH level was available for 22 patients. The majority of repleted patients had a normal posttreatment level (63.6%). The postsupplementation level corrected into the insufficient range for 31.8% of patients and 4.6% remained deficient. Vitamin D insufficiency and deficiency are common following HSCT. Further investigation into potential risk factors and the appropriate supplementation for these patients is warranted.