Vitamin D in children and adolescents with sickle cell disease: an integrative review

OBJECTIVE To review the literature about the prevalence of vitamin D deficiency and its consequences in children and adolescents with sickle-cell disease. DATA SOURCES The literature survey was performed through the bibliographic databases Medline; U.S. National Library of Medicine and National Institutes of Health (PubMed); Literatura Latino-Americana e do Caribe em Ciências da Saúde (Lilacs), and the Cochrane Library. The keywords were selected using Medical Heading Terms (MeSH): "Vitamin D" OR "Vitamin D deficiency" AND "Anemia, Sickle Cell" AND "Child" AND "Adolescent". The search was limited to articles in English, Spanish and Portuguese, published until April 2014. DATA SYNTHESIS Eleven articles were selected among the 18 found. In 6 of the 11 studies, serum levels of vitamin D in children and/or adolescents with sickle-cell anemia were low. The prevalence of vitamin D deficiency in patients with sickle-cell anemia exceeded that of the comparison group. The low intake of vitamin D, seasonality, exposure to sun, increased metabolism associated with the hemoglobinopathy, and age increase were factors associated with the deficiency. There was an association between a significant vitamin D deficiency and bone weakness and painful crises. There was a positive correlation between increased levels of vitamin D by supplementation and functional, physical capacity. CONCLUSIONS The vitamin D deficiency in children and adolescents with sickle-cell disease is prevalent and requires further studies to demonstrate its association with comorbidities and possible benefits of vitamin D supplementation.