title: Cord blood vitamin D deficiency is associated with respiratory syncytial virus bronchiolitis.
abstract: BACKGROUND
  Respiratory syncytial virus (RSV) is the most important pathogen causing severe lower respiratory tract infection (LRTI) in infants. Epidemiologic and basic studies suggest that vitamin D may protect against RSV LRTI.
  
  
  OBJECTIVE
  To determine the association between plasma vitamin D concentrations at birth and the subsequent risk of RSV LRTI.
  
  
  METHODS
  A prospective birth cohort study was performed in healthy term neonates. Concentrations of 25-hydroxyvitamin D (25-OHD) in cord blood plasma were related to RSV LRTI in the first year of life, defined as parent-reported LRTI symptoms in a daily log and simultaneous presence of RSV RNA in a nose-throat specimen.
  
  
  RESULTS
  The study population included 156 neonates. Eighteen (12%) developed RSV LRTI. The mean plasma 25-OHD concentration was 82 nmol/L. Overall, 27% of neonates had 25-OHD concentrations < 50 nmol/L, 27% had 50-74 nmol/L and only 46% had 25-OHD 75 nmol/L. Cord blood 25-OHD concentrations were strongly associated with maternal vitamin D3 supplementation during pregnancy. Concentrations of 25-OHD were lower in neonates who subsequently developed RSV LRTI compared with those who did not (65 nmol/L versus 84 nmol/L, P = .009). Neonates born with 25-OHD concentrations <50 nmol/L had a sixfold (95% confidence interval: 1.6-24.9; P = .01) increased risk of RSV LRTI in the first year of life compared with those with 25-OHD concentrations ≥ 75 nmol/L.
  
  
  CONCLUSIONS
  Vitamin D deficiency in healthy neonates is associated with increased risk of RSV LRTI in the first year of life. Intensified routine vitamin D supplementation during pregnancy may be a useful strategy to prevent RSV LRTI during infancy.
authors.affiliation: Department of Pediatrics, University Medical Center Utrecht, Utrecht.
authors.forename: Mirjam E
authors.initials: ME
authors.lastname: Belderbos
authors.forename: Michiel L
authors.initials: ML
authors.lastname: Houben
authors.forename: Berry
authors.initials: B
authors.lastname: Wilbrink
authors.forename: Eef
authors.initials: E
authors.lastname: Lentjes
authors.forename: Eltje M
authors.initials: EM
authors.lastname: Bloemen
authors.forename: Jan L L
authors.initials: JL
authors.lastname: Kimpen
authors.forename: Maroeska
authors.initials: M
authors.lastname: Rovers
authors.forename: Louis
authors.initials: L
authors.lastname: Bont
mesh_terms: D001988:Bronchiolitis / Q000097:blood* / Q000150:complications / Q000821:virology; D005260:Female; D005312:Fetal Blood / Q000378:metabolism*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious; D011446:Prospective Studies; D012367:RNA, Viral / Q000032:analysis; D018357:Respiratory Syncytial Virus Infections / Q000097:blood* / Q000150:complications / Q000821:virology; D012136:Respiratory Syncytial Viruses / Q000235:genetics; D012307:Risk Factors; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood* / Q000150:complications
chemical_list: D012367:RNA, Viral; D014807:Vitamin D; C104450:25-hydroxyvitamin D