title: Assessment of vitamin A status with the relative-dose-response test in Peruvian children recovering from pneumonia.
abstract: BACKGROUND
  The relative-dose-response (RDR) test is used to identify subjects with marginal liver vitamin A stores, but its use has not been evaluated during episodes of infection.
  
  
  OBJECTIVE
  The objective was to assess, with the RDR test, the vitamin A status of children recovering from pneumonia.
  
  
  METHODS
  As part of a double-blind, placebo-controlled clinical trial of high-dose vitamin A supplements among children hospitalized with pneumonia in Lima, Peru, we examined the association of treatment group, nutritional status, severity of disease, and induction of the acute phase response [on the basis of serum C-reactive protein (CRP)] on serum retinol and the RDR test.
  
  
  RESULTS
  Serum retinol was low at admission and increased significantly in both the vitamin A and placebo groups during recovery. Serum CRP had a significant, inverse association with retinol at both admission and discharge. Serum retinol and CRP concentrations never differed significantly between the treatment groups. Among subjects with CRP > or =10 mg/L, 21% in the vitamin A group and 20% in the placebo groups (P = 0.83) had a positive RDR test result. Among subjects with CRP <10 mg/L, 56% in the placebo group but only 6% in the vitamin A group had positive RDR test results (P = 0.002).
  
  
  CONCLUSIONS
  The RDR test was useful in assessing the vitamin A status of children recovering from pneumonia when CRP concentrations were <10 mg/L but not when CRP concentrations were higher.
authors.affiliation: Department of Epidemiology and International Health, School of Public Health, University of Alabama at Birmingham, USA. cstephensen@ucdavis.udu
authors.forename: Charles B
authors.initials: CB
authors.lastname: Stephensen
authors.forename: Luis Miguel
authors.initials: LM
authors.lastname: Franchi
authors.forename: Herminio
authors.initials: H
authors.lastname: Hernandez
authors.forename: Miguel
authors.initials: M
authors.lastname: Campos
authors.forename: Ana
authors.initials: A
authors.lastname: Colarossi
authors.forename: Robert H
authors.initials: RH
authors.lastname: Gilman
authors.forename: Jose O
authors.initials: JO
authors.lastname: Alvarez
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D002097:C-Reactive Protein / Q000032:analysis; D002675:Child, Preschool; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009752:Nutritional Status; D010568:Peru; D010919:Placebos; D018410:Pneumonia, Bacterial / Q000097:blood / Q000628:therapy*; D011024:Pneumonia, Viral / Q000097:blood / Q000628:therapy*; D014801:Vitamin A / Q000008:administration & dosage* / Q000097:blood*; D014802:Vitamin A Deficiency / Q000175:diagnosis
chemical_list: D000900:Anti-Bacterial Agents; D010919:Placebos; D014801:Vitamin A; D002097:C-Reactive Protein