title: Systematic review and meta-analysis: Prevalence and possible causes of vitamin D deficiency and insufficiency in pediatric cancer patients.
abstract: OBJECTIVE
  Vitamin D inadequacy is now an internationally recognized health problem and pediatric cancer patients may be at even higher risk than healthy children. We aimed to evaluate primary research to establish the prevalence of vitamin D inadequacy and to explore its possible causes in pediatric cancer patients.
  
  
  METHODS
  Electronic databases were searched (no restriction-Aug 2013) with no language restrictions and keywords related to cancer and vitamin D. We included studies of patients aged <18 years, diagnosed with and treated for cancer and reporting plasma vitamin D status. Evidence was critically appraised employing the CASP tool. Meta-analysis was performed when appropriate.
  
  
  RESULTS
  We included 19 studies, which were mainly of moderate-quality and heterogeneous in the definitions of vitamin D deficiency and insufficiency. The median (range) prevalence of vitamin D deficiency was 14% (0-61.5%) and insufficiency 23% (0-83%). Finally, a significant effect of younger age with vitamin D inadequacy was shown (effect size: -0.132; 95%CI -0.203, -0.060).
  
  
  CONCLUSIONS
  There is a possibility of a high prevalence of vitamin D inadequacy in pediatric cancer patients, especially older children, urging the need for high-quality population-based longitudinal studies using standard definitions.
authors: Dietetics, Nutrition and Biological Health Sciences, Queen Margaret University, Edinburgh, UK; Department of Child Life and Health, University of Edinburgh, Edinburgh, UK. Electronic address: rrevueltainiesta@qmu.ac.uk.
authors: R
authors: R
authors: Revuelta Iniesta
authors: Dietetics, Nutrition and Biological Health Sciences, Queen Margaret University, Edinburgh, UK.
authors: R
authors: R
authors: Rush
authors: Dietetics, Nutrition and Biological Health Sciences, Queen Margaret University, Edinburgh, UK; Department of Child Life and Health, University of Edinburgh, Edinburgh, UK.
authors: I
authors: I
authors: Paciarotti
authors: Department of Paediatrics, Victoria Hospital, Kirkcaldy, Fife, UK.
authors: E B
authors: EB
authors: Rhatigan
authors: Department of Haematology and Oncology, Royal Hospital for Sick Children, Edinburgh, UK.
authors: F H M
authors: FHM
authors: Brougham
authors: Dietetics, Nutrition and Biological Health Sciences, Queen Margaret University, Edinburgh, UK.
authors: J M
authors: JM
authors: McKenzie
authors: Department of Child Life and Health, University of Edinburgh, Edinburgh, UK.
authors: D C
authors: DC
authors: Wilson
mesh_terms: D000293:Adolescent; D002648:Child; D016208:Databases, Factual; D019587:Dietary Supplements; D006801:Humans; D009369:Neoplasms / Q000097:blood*; D010281:Parathyroid Hormone / Q000097:blood; D015995:Prevalence; D014807:Vitamin D / Q000008:administration & dosage / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood* / Q000453:epidemiology*
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D
keywords: 25(OH)D status,1,25(OH)D; Pediatric cancer; Prevalence; Vitamin D; Vitamin D deficiency