title: Influence of serum 25-hydroxyvitamin D on the rate of pain episodes in Nigerian children with sickle cell anaemia.
abstract: BACKGROUND
  In sickle cell disease (SCD), symptoms of vitamin D deficiency (VDD) and chronic pain can overlap.
  
  
  OBJECTIVE
  To examine the relationship between serum vitamin D levels and the frequency of acute pain episodes.
  
  
  METHODS
  In this cross-sectional study, serum 25-hydroxyvitamin D (25-OHD) was assayed by high-performance liquid chromatography, and its influence on the number of significant pain episodes was examined by bivariate and logistic regression analyses.
  
  
  RESULTS
  The mean (SD) serum 25-OHD level in 123 children with SCD (HbSS) was 105.8 (24.1) nmol/L (range 37.5-155.8). Fourteen patients (11.4%) either had a deficient (1.6%) or insufficient (9.8%) level. None had severe VDD. All the children with sub-optimal vitamin D experienced pain, as did 69.7% of those with normal vitamin D [14 (100%) vs 76 (69.7%), 95% CI 0.7-0.9, p = 0.04]. The mean serum vitamin D level in the 90 patients with at least one pain episode [103.1 (25.2) nmol/L] was significantly lower than the 113.1 (19.3) nmol/L in the 33 without a pain episode (95% CI 1.3-7.8, p = 0.04). The frequency of pain correlated inversely with the serum 25-OHD level. Serum levels of vitamin D (OR 1.2, 95% CI 1.3-1.7, p = 0.04) and fetal haemoglobin concentration (OR 1.6, 95% CI 1.1-1.4, p = 0.02) predicted significant pain episodes.
  
  
  CONCLUSIONS
  In children with SCD, there is a possible association between depressed serum vitamin D levels and increased frequency of acute pain episodes. Vitamin D supplements should be considered in patients with low levels and frequent episodes of pain.
authors.affiliation: a Haematology and Blood Transfusion Division , Escola Paulista de Medicina, Universidade Federal de São Paulo , São Paulo , Brazil.|b Department of Pediatrics and Child Health , Obafemi Awolowo University , Ile-Ife , Nigeria.
authors.forename: Samuel Ademola
authors.initials: SA
authors.lastname: Adegoke
authors.affiliation: b Department of Pediatrics and Child Health , Obafemi Awolowo University , Ile-Ife , Nigeria.
authors.forename: Oyeku Akibu
authors.initials: OA
authors.lastname: Oyelami
authors.affiliation: c Faculty of Medicine, Department of Paediatrics , Kuwait University , Kuwait City , Kuwait.
authors.forename: Adekunle
authors.initials: A
authors.lastname: Adekile
authors.affiliation: a Haematology and Blood Transfusion Division , Escola Paulista de Medicina, Universidade Federal de São Paulo , São Paulo , Brazil.
authors.forename: Maria Stella
authors.initials: MS
authors.lastname: Figueiredo
mesh_terms: D000293:Adolescent; D000755:Anemia, Sickle Cell / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009549:Nigeria; D010146:Pain / Q000453:epidemiology*; D044967:Serum / Q000737:chemistry*; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: 25-hydroxyvitamin D; Children; sickle cell disease; vaso-occlusive crisis