title: Cord-blood 25-hydroxyvitamin D levels and risk of respiratory infection, wheezing, and asthma.
abstract: OBJECTIVE
  Higher maternal intake of vitamin D during pregnancy is associated with a lower risk of wheezing in offspring. The relationship between cord-blood levels of 25-hydroxyvitamin D (25[OH]D) and childhood wheezing is unknown. We hypothesized that cord-blood levels would be inversely associated with risk of respiratory infection, wheezing, and asthma.
  
  
  METHODS
  Cord blood from 922 newborns was tested for 25(OH)D. Parents were asked if their child had a history of respiratory infection at 3 months of age or a history of wheezing at 15 months of age and then annually thereafter. Incident asthma was defined as doctor-diagnosed asthma by the time the child was 5 years old and reported inhaler use or wheezing since the age of 4 years.
  
  
  RESULTS
  The median cord-blood level of 25(OH)D was 44 nmol/L (interquartile range: 29-78). Follow-up was 89% at the age of 5 years. Adjusting for the season of birth, 25(OH)D had an inverse association with risk of respiratory infection by 3 months of age (odds ratio: 1.00 [reference] for ≥75 nmol/L, 1.39 for 25-74 nmol/L, and 2.16 [95% confidence interval: 1.35-3.46] for <25 nmol/L). Likewise, cord-blood 25(OH)D levels were inversely associated with risk of wheezing by 15 months, 3 years, and 5 years of age (all P < .05). Additional adjustment for more than 12 potential confounders did not materially change these results. In contrast, we found no association between 25(OH)D levels and incident asthma by the age of 5 years.
  
  
  CONCLUSIONS
  Cord-blood levels of 25(OH)D had inverse associations with risk of respiratory infection and childhood wheezing but no association with incident asthma.
authors.affiliation: Center for D-receptor Activation Research, Massachusetts General Hospital, 326 Cambridge St, Suite 410, Boston, MA 02114, USA. ccamargo@partners.org
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Camargo
authors.forename: Tristram
authors.initials: T
authors.lastname: Ingham
authors.forename: Kristin
authors.initials: K
authors.lastname: Wickens
authors.forename: Ravi
authors.initials: R
authors.lastname: Thadhani
authors.forename: Karen M
authors.initials: KM
authors.lastname: Silvers
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Epton
authors.forename: G Ian
authors.initials: GI
authors.lastname: Town
authors.forename: Philip K
authors.initials: PK
authors.lastname: Pattemore
authors.forename: Janice A
authors.initials: JA
authors.lastname: Espinola
authors.forename: Julian
authors.initials: J
authors.lastname: Crane
mesh_terms: D001249:Asthma / Q000097:blood* / Q000453:epidemiology*; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011446:Prospective Studies; D012135:Respiratory Sounds; D012141:Respiratory Tract Infections / Q000097:blood* / Q000453:epidemiology*; D012307:Risk Factors; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D