title: Influence of early-life exposures on food sensitization and food allergy in an inner-city birth cohort.
abstract: OBJECTIVE
  Previous data suggest that food allergy (FA) might be more common in inner-city children; however, these studies have not collected data on both sensitization and clinical reactivity or early-life exposures.
  
  
  METHODS
  Children in the Urban Environment and Childhood Asthma birth cohort were followed through age 5 years. Household exposures, diet, clinical history, and physical examinations were assessed yearly; levels of specific IgE to milk, egg, and peanut were measured at 1, 2, 3, and 5 years of age. On the basis of sensitization (IgE ≥0.35 kU/L) and clinical history over the 5-year period, children were classified as having FA or being possibly allergic, sensitized but tolerant, or not allergic/not sensitized.
  
  
  RESULTS
  Five hundred sixteen children were included. Overall, 55.4% were sensitized (milk, 46.7%; egg, 31.0%; and peanut, 20.9%), whereas 9.9% were categorized as having FA (peanut, 6.0%; egg, 4.3%; and milk, 2.7%; 2.5% to >1 food). The remaining children were categorized as possibly allergic (17.0%), sensitized but tolerant (28.5%), and not sensitized (44.6%). Eighteen (3.5%) reported reactions to foods for which IgE levels were not measured. Food-specific IgE levels were similar in children with FA versus sensitized but tolerant children, except for egg, levels of which were higher in patients with FA at ages 1 and 2 years. FA was associated with recurrent wheeze, eczema, aeroallergen sensitization, male sex, breast-feeding, and lower endotoxin exposure in year 1 but not with race/ethnicity, income, tobacco exposure, maternal stress, or early introduction of solid foods.
  
  
  CONCLUSIONS
  Even given that this was designed to be a high-risk cohort, the cumulative incidence of FA is extremely high, especially considering the strict definition of FA that was applied and that only 3 common allergens were included.
authors.affiliation: Department of Medicine, Division of Allergy and Clinical Immunology, Johns Hopkins University School of Medicine, and the Johns Hopkins Bloomberg School of Public Health, Baltimore, Md.
authors.forename: Emily C
authors.initials: EC
authors.lastname: McGowan
authors.affiliation: Division of Allergy, Immunology, and Pulmonary Medicine, Washington University School of Medicine, St Louis, Mo.
authors.forename: Gordon R
authors.initials: GR
authors.lastname: Bloomberg
authors.affiliation: National Institutes of Health, National Institute of Allergy and Infectious Diseases, Bethesda, Md.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Gergen
authors.affiliation: Rho, Inc, Chapel Hill, NC.
authors.forename: Cynthia M
authors.initials: CM
authors.lastname: Visness
authors.affiliation: Rho, Inc, Chapel Hill, NC.
authors.forename: Katy F
authors.initials: KF
authors.lastname: Jaffee
authors.affiliation: Department of Medicine, Division of Pediatric Primary Care, Boston University School of Medicine, Boston, Mass.
authors.forename: Megan
authors.initials: M
authors.lastname: Sandel
authors.affiliation: Department of Medicine, Division of Pulmonary, Allergy, Sleep, and Critical Care Medicine, Boston University School of Medicine, Boston, Mass.
authors.forename: George
authors.initials: G
authors.lastname: O'Connor
authors.affiliation: Department of Pediatrics, Division of Pediatric Pulmonology, New York Presbyterian/Columbia University Medical Center, New York, NY.
authors.forename: Meyer
authors.initials: M
authors.lastname: Kattan
authors.affiliation: Department of Pediatrics, Division of Allergy and Immunology, University of Wisconsin School of Medicine, Madison, Wis.
authors.forename: James
authors.initials: J
authors.lastname: Gern
authors.affiliation: Division of Allergy and Immunology, Johns Hopkins University School of Medicine, Department of Pediatrics, Baltimore, Md. Electronic address: rwood@jhmi.edu.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Wood
mesh_terms: D000485:Allergens / Q000032:analysis*; D002675:Child, Preschool; D002947:Cities / Q000453:epidemiology; D015331:Cohort Studies; D016207:Cytokines / Q000276:immunology; D004391:Dust / Q000032:analysis; D021181:Egg Hypersensitivity / Q000097:blood / Q000453:epidemiology*; D004781:Environmental Exposure / Q000009:adverse effects / Q000032:analysis*; D005260:Female; D054624:Health Status Disparities; D006798:Housing; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D008297:Male; D016269:Milk Hypersensitivity / Q000097:blood / Q000453:epidemiology*; D021183:Peanut Hypersensitivity / Q000097:blood / Q000453:epidemiology*; D015995:Prevalence; D014481:United States / Q000453:epidemiology; D014505:Urban Population / Q000706:statistics & numerical data*
chemical_list: D000485:Allergens; D016207:Cytokines; D004391:Dust; D007074:Immunoglobulin G; D007073:Immunoglobulin E
keywords: Food allergy; Urban Environment and Childhood Asthma cohort; inner city; specific IgE