Vitamin D supplementation for sickle cell disease

Area of Science:

• Hematology
• Nutritional Science
• Clinical Trials

Background:

• Sickle cell disease (SCD) is a chronic, pro-inflammatory disorder associated with nutritional deficiencies, including vitamin D.
• Individuals with SCD often experience increased nutrient catabolism and reduced intake, exacerbating these deficiencies.

Purpose of the Study:

• To evaluate the effects of vitamin D supplementation in children and adults with SCD.
• To compare different vitamin D dosage regimens and assess impacts on general health, musculoskeletal and respiratory health, and safety.

Main Methods:

• Searched multiple databases and trial registries for randomized controlled trials (RCTs) and quasi-RCTs.
• Included studies comparing any oral vitamin D supplementation to placebo or no supplementation in individuals with SCD.
• Two authors independently extracted data and assessed study bias using GRADE guidelines.

Main Results:

• One RCT showed vitamin D supplementation likely increased serum 25(OH)D levels and possibly reduced pain days, but may have negatively impacted quality of life.
• Comparing different vitamin D doses, higher doses may increase serum 25(OH)D levels but could be associated with more acute chest syndrome episodes and reduced forced vital capacity.
• Evidence quality across studies was generally low to moderate, with significant risk of bias noted in several areas.

Conclusions:

• The current evidence on vitamin D supplementation in SCD is of insufficient quality to guide clinical practice.
• Existing guidelines for vitamin D and calcium intake should be considered.
• Well-designed RCTs are needed to clarify the effects, safety, and optimal dosing of vitamin D supplementation in SCD.