Cobalamin Deficiency in Children and Adolescents with Sickle Cell Disease

Area of Science:

• Pediatric Hematology
• Nutritional Science
• Clinical Diagnostics

Background:

• Cobalamin (Vitamin B12) deficiency is more prevalent in adults with sickle cell disease (SCD) than the general population.
• Limited data exist on Vitamin B12 deficiency in children with SCD, particularly concerning diagnosis and potential impacts of treatments like nitrous oxide (N2O).
• Nitrous oxide (N2O) is used for SCD pain management in some regions and can interfere with Vitamin B12 metabolism.

Purpose of the Study:

• To evaluate the prevalence of Vitamin B12 deficiency in children hospitalized with SCD pain.
• To investigate potential diagnostic challenges and biomarkers for Vitamin B12 deficiency in this pediatric population.

Main Methods:

• A secondary analysis was performed on prospective blood and urine samples from children aged 3-21 with SCD pain.
• Vitamin B12 deficiency was defined using plasma methylmalonic acid (MMA) levels (> 592 nmol/L) or urine MMA/creatinine ratio (≥ 2.2 mmol/mol).
• Data were analyzed to determine the prevalence of deficiency by various diagnostic criteria and to assess correlations with clinical parameters.

Main Results:

• Of 94 children assessed (mean age 13 years, 54% female, 68% hemoglobin-SS), 53% (50/94) showed evidence of Vitamin B12 deficiency.
• Deficiency was diagnosed in 27% by urine MMA/creatinine, 39% by plasma MMA, and 13% by both methods.
• Plasma MMA and urine MMA/creatinine did not correlate with hemoglobin levels or mean corpuscular volume.

Conclusions:

• Vitamin B12 deficiency is a common finding in children with SCD.
• The lack of a gold standard diagnostic test and variability in testing modalities complicate accurate prevalence determination.
• Further research is needed to understand Vitamin B12 metabolism dynamics in SCD during acute and steady states.