vitamin d supplementation in children with sickle cell disease

Conditions: Sickle Cell Disease

Summary: sickle cell disease (scd) is a genetic disease characterized by abnormal hemoglobin, the main constituent of red blood cells. people with scd have nutritional deficiencies, and vitamin d deficiency is one of the most common. symptoms of vitamin d deficiency are similar to those of scd and include chronic pain and bone complications. correcting vitamin d nutrition of children with scd represents a treatment that will improve their health. a single oral high-dose of vitamin d3 will be given to scd children during one of their follow-up visits at the scd clinic of chu sainte-justine, montreal, canada. this mode of administration was chosen to ensure a better adherence to the treatment. the investigators will determine whether this dose is safe and its administration feasible in clinic. the impact of this dose on blood vitamin d and calcium, urinary calcium, growth, inflammation, bone health, pain and quality of life will also be assessed. this study intends to propose a new intervention to improve the nutrition of children with this disease.

vitamin d deficiency is one of the most common nutritional conditions among patients with sickle cell disease (scd). since vitamin d deficiency and scd share common manifestations including chronic pain, poor bone health and chronic systemic inflammation, it is reasonable to postulate that vitamin d deficiency may contribute to these complications. thus, optimizing vitamin d nutrition represents an inexpensive strategy that may improve vitamin d status and health outcomes in scd children. the working hypothesis is that administration of a single oral bolus of 300,000 iu of vitamin d3 to scd children will result in the attainment of vitamin d sufficiency (25ohd levels \>75 nmol/l) in 80% of participants after 3 months. the primary objectives are to assess feasibility, acceptability, and safety of the vitamin d3 bolus while secondary objectives are related to the mean change in serum 25ohd from baseline to 3 months post-bolus and its clinical impact. seventy-two scd children (5-17 years, ss and sc genotypes) will be randomized to one bolus of 300,000 iu of vitamin d3 or identical placebo. blood will be collected at baseline and 3-month post-bolus to measure serum 25ohd and calculate the change from baseline at 3 months (efficacy outcomes). other outcomes include urinary calcium/creatinine ratio and serum calcium (safety), questionnaires (acceptability and musculoskeletal pain) and parameters related to growth, haematology, inflammation and bone health (exploratory outcomes).

Eligibility criteria:
inclusion criteria: * children aged between 5 and 17 years old who are followed up at the scd clinic, chu sainte-justine, montreal, canada. exclusion criteria: * conditions or use of medications known to interfere with calcium or vitamin d absorption or metabolism * known hypercalcemia * conditions characterized by a hypersensitivity to vitamin d (e.g. granulomatous disorders) * patients clinically diagnosed with rickets or other conditions requiring vitamin d therapy * history or presence of urolithiasis * anticipated difficult follow up * patients already enrolled in other investigational studies * patients who have recently been hospitalized for severe pain crisis or acute sickle complication in the past 2 weeks * patients with unresolved pain issues

Keywords: bolus supplementation pilot randomised controlled trial vitamin d