title: Association between vitamin D levels and allergy-related outcomes vary by race and other factors.
abstract: BACKGROUND
  Allergy-related studies that include biological measurements of vitamin D preceding well-measured outcomes are needed.
  
  
  OBJECTIVE
  We sought to examine the associations between early-life vitamin D levels and the development of allergy-related outcomes in the racially diverse Wayne County Health, Environment, Allergy, and Asthma Longitudinal Study birth cohort.
  
  
  METHODS
  25-Hydroxyvitamin D (25[OH]D) levels were measured in stored blood samples from pregnancy, cord blood, and age 2 years. Logistic regression models were used to calculate odds ratios (ORs) with 95% CIs for a 5 ng/mL increase in 25(OH)D levels for the following outcomes at age 2 years: eczema, skin prick tests (SPTs), increased allergen-specific IgE level (≥ 0.35 IU/mL), and doctor's diagnosis of asthma (3-6 years).
  
  
  RESULTS
  Prenatal 25(OH)D levels were inversely associated with eczema (OR, 0.85; 95% CI, 0.75-0.96). The association was stronger in white children (white children: OR, 0.79; 95% CI, 0.57-1.09; black children: OR, 0.96; 95% CI, 0.82-1.12), although this was not statistically significant. Cord blood 25(OH)D levels were inversely associated with having 1 or more positive SPT responses and aeroallergen sensitization. Both associations were statistically significant in white children (positive SPT response: OR, 0.50; 95% CI, 0.32-0.80; ≥ 1 aeroallergen sensitization: OR, 0.50; 95% CI, 0.28-0.92) in contrast with black children (positive SPT response: OR, 0.88; 95% CI, 0.68-1.14; ≥ 1 aeroallergen sensitization: OR, 0.85; 95% CI, 0.65-1.11). 25(OH)D levels measured concurrently with outcome assessment were inversely associated with aeroallergen sensitization (OR, 0.79; 95% CI, 0.66-0.96) only among black children (white children: OR, 1.21; 95% CI, 0.87-1.69).
  
  
  CONCLUSIONS
  Prenatal and cord blood 25(OH)D levels were associated with some allergy-related outcomes, with a general pattern indicating that children with higher 25(OH)D levels tend to have fewer allergy-related outcomes.
authors.affiliation: Department of Public Health Sciences, Henry Ford Hospital, Detroit, Mich. Electronic address: gwegien1@hfhs.org.
authors.forename: Ganesa
authors.initials: G
authors.lastname: Wegienka
authors.affiliation: Department of Public Health Sciences, Henry Ford Hospital, Detroit, Mich.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Havstad
authors.affiliation: Department of Internal Medicine, Division of Allergy, Henry Ford Hospital, Detroit, Mich.
authors.forename: Edward M
authors.initials: EM
authors.lastname: Zoratti
authors.affiliation: Department of Internal Medicine, Division of Allergy, Henry Ford Hospital, Detroit, Mich.
authors.forename: Haejin
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Georgia Regents University, Augusta, Ga.
authors.forename: Dennis R
authors.initials: DR
authors.lastname: Ownby
authors.affiliation: Department of Public Health Sciences, Henry Ford Hospital, Detroit, Mich.
authors.forename: Christine Cole
authors.initials: CC
authors.lastname: Johnson
mesh_terms: D002675:Child, Preschool; D015331:Cohort Studies; D004485:Eczema / Q000453:epidemiology / Q000276:immunology*; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology* / Q000276:immunology; D007114:Immunization; D007073:Immunoglobulin E / Q000097:blood; D008297:Male; D011247:Pregnancy; D044469:Racial Groups; D012307:Risk Factors; D014807:Vitamin D / Q000097:blood*
chemical_list: D014807:Vitamin D; D007073:Immunoglobulin E
keywords: IgE; Vitamin D; allergy; asthma; eczema; racial differences