title: Prevalence of allergy symptoms and total IgE in a New York City cohort and their association with birth order.
abstract: BACKGROUND
  An inverse association between birth order and allergic disease has been widely observed, but has not been examined in the high asthma prevalence, inner-city populations of the United States. As part of an ongoing prospective birth cohort study, the prevalence of early phenotypes of asthma and/or allergy was compared with those reported in other studies, and the association with birth order was evaluated.
  
  
  METHODS
  Children of Dominican and African-American mothers living in Northern Manhattan underwent detailed periodic questionnaires. Total IgE from the mothers (n = 321) and the children at birth (n = 291) and at ages 24 (n = 244) and 36 (n = 155) months was measured. The association between birth order and allergy symptoms was evaluated at 12 (n = 350), 24 (n = 290) and 36 (n = 247) months.
  
  
  RESULTS
  Total serum IgE was detectable (>0.5 IU/ml) in 35% of the children's cord blood and averaged 15 and 21 IU/ml at ages 24 and 36 months, respectively. They were not significantly different at any age between children with and without older siblings. Additionally, at these ages, there were no consistent associations between birth order and either wheeze, itchy eyes or eczema.
  
  
  CONCLUSIONS
  Despite a substantially higher prevalence of asthma in the Northern Manhattan community compared with other areas, total IgE levels at ages 24 and 36 months, but not cord blood, are similar to those reported in other areas of the world. In this community, results at this age do not support a protective effect of higher birth order.
authors.affiliation: Columbia's Children's Center for Environmental Health (CCCEH), Columbia University, New York, NY, USA. ifg2@columbia.edu
authors.forename: Inge F
authors.initials: IF
authors.lastname: Goldstein
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Perzanowski
authors.forename: Cynthia
authors.initials: C
authors.lastname: Lendor
authors.forename: Robin S
authors.initials: RS
authors.lastname: Garfinkel
authors.forename: Lori A
authors.initials: LA
authors.lastname: Hoepner
authors.forename: Ginger L
authors.initials: GL
authors.lastname: Chew
authors.forename: Frederica P
authors.initials: FP
authors.lastname: Perera
authors.forename: Rachel L
authors.initials: RL
authors.lastname: Miller
mesh_terms: D000293:Adolescent; D000328:Adult; D001741:Black or African American; D001249:Asthma / Q000453:epidemiology* / Q000276:immunology; D001722:Birth Order; D002675:Child, Preschool; D004293:Dominican Republic; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000175:diagnosis / Q000453:epidemiology*; D007073:Immunoglobulin E / Q000097:blood*; D007223:Infant; D008297:Male; D009519:New York City; D015995:Prevalence; D011795:Surveys and Questionnaires
chemical_list: D007073:Immunoglobulin E