title: Boys with high body masses have an increased risk of developing asthma: findings from the National Longitudinal Survey of Youth (NLSY).
abstract: OBJECTIVE
  To determine the relation between body mass index and the development of asthma in children.
  
  
  METHODS
  Prospective study of 4393 asthma-free children followed for up to 14 years.
  
  
  METHODS
  Children of participants in the National Longitudinal Survey of Youth.
  
  
  METHODS
  Analysis was limited to children who were followed from birth and were asthma-free during the first 24 months of life. The outcome was the development of asthma during follow-up (incident asthma). Body mass index (BMI) was our main predictor of interest. Survival analyses, using time to development of asthma as the main endpoint, were stratified by sex and controlled for race/ethnicity, poverty status, and prenatal maternal smoking.
  
  
  RESULTS
  Asthma developed in 218 (5.0 %) children during the follow-up period. The relation between BMI and incident asthma varied by sex. A BMI > or =85th percentile at age 2-3 years was a risk factor for subsequent asthma development in boys (hazard ratio (HR) 1.6 95% confidence interval (CI) 1.1, 2.4) but not girls (HR 0.8, 95% CI 0.5, 1.4). Similarly, boys with BMIs always > or =85th percentile were at increased risk for subsequent asthma development (HR 2.4, 95% CI 1.4, 4.4) but not girls (HR 1.5, 95% CI 0.7, 2.9).
  
  
  CONCLUSIONS
  Boys with high body masses may be at an increased risk for developing asthma.
authors.affiliation: Division of Pulmonary, Critical Care and Sleep Medicine, University of Kentucky Medical Center, Lexington, 40536, USA. dmannino@uky.edu
authors.forename: D M
authors.initials: DM
authors.lastname: Mannino
authors.forename: J
authors.initials: J
authors.lastname: Mott
authors.forename: J M
authors.initials: JM
authors.lastname: Ferdinands
authors.forename: C A
authors.initials: CA
authors.lastname: Camargo
authors.forename: M
authors.initials: M
authors.lastname: Friedman
authors.forename: H M
authors.initials: HM
authors.lastname: Greves
authors.forename: S C
authors.initials: SC
authors.lastname: Redd
mesh_terms: D001249:Asthma / Q000453:epidemiology / Q000209:etiology*; D001724:Birth Weight; D015992:Body Mass Index; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D009035:Mothers / Q000523:psychology; D009765:Obesity / Q000150:complications* / Q000453:epidemiology; D011203:Poverty / Q000706:statistics & numerical data; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012737:Sex Factors; D012907:Smoking; D014481:United States / Q000453:epidemiology