title: Disease activity, proteinuria, and vitamin D status in children with systemic lupus erythematosus and juvenile dermatomyositis.
abstract: OBJECTIVE
  To evaluate relationships among vitamin D, proteinuria, and disease activity in pediatric systemic lupus erythematosus (SLE) and juvenile dermatomyositis (JDM).
  
  
  METHODS
  Multiple linear regression was used to associate subject-reported race, sunscreen use, and vitamin D intake with physician-assessed disease activity and serum 25-hydroxyvitamin D (25[OH]D) in 58 subjects with pediatric SLE (n=37) or JDM (n=21). Serum 25(OH)D was correlated with urinary vitamin D binding protein/creatinine ratio (DBP/C) and other indicators of proteinuria.
  
  
  RESULTS
  Serum 25(OH)D levels in subjects with SLE were inversely associated with the natural log of urinary DBP/C (r=-0.63, P<.001) and urine protein to creatinine ratio (r=-0.60, P<.001), with an adjusted mean 10.9-ng/mL (95% CI, 5.1-16.8) decrease in 25(OH)D for those with proteinuria. Excluding subjects with proteinuria, serum 25(OH)D levels were inversely associated with disease activity in JDM, but not in SLE. Overall, 66% of all subjects were taking concurrent corticosteroids, but this was not associated with 25(OH)D levels.
  
  
  CONCLUSIONS
  Low serum 25(OH)D in patients with SLE is associated with proteinuria and urinary DBP. Vitamin D deficiency is associated with disease activity in patients with JDM and SLE; this relationship in SLE may be confounded by proteinuria.
authors.affiliation: Division of Pediatric Rheumatology, Rainbow Babies and Children's Hospital, Cleveland, OH 44106, USA.
authors.forename: Angela Byun
authors.initials: AB
authors.lastname: Robinson
authors.forename: Myrtle
authors.initials: M
authors.lastname: Thierry-Palmer
authors.forename: Keisha L
authors.initials: KL
authors.lastname: Gibson
authors.forename: Consuelo Egla
authors.initials: CE
authors.lastname: Rabinovich
mesh_terms: D000293:Adolescent; D002648:Child; D003404:Creatinine / Q000652:urine; D003882:Dermatomyositis / Q000097:blood / Q000503:physiopathology* / Q000652:urine; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood / Q000503:physiopathology* / Q000652:urine; D008297:Male; D011446:Prospective Studies; D011507:Proteinuria / Q000652:urine*; D012307:Risk Factors; D012720:Severity of Illness Index; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications / Q000503:physiopathology* / Q000652:urine
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D; D003404:Creatinine