title: Secondhand smoke and traffic exhaust confer opposing risks for asthma in normal and overweight children.
abstract: OBJECTIVE
  Exposure to ultrafine particles (UFP) in secondhand smoke (SHS) and traffic-related air pollution (TRAP) may elicit chronic inflammation. It was hypothesized that the association between these exposures would be potentiated in overweight versus normal-weight children.
  
  
  METHODS
  Average lifetime exposure to TRAP and SHS and objective, physician-diagnosed asthma were determined for 575 children at age 7. Overweight was defined as having a body mass index (BMI) >85th percentile for age and gender. The association between TRAP and SHS exposure and asthma was examined by logistic regression stratified by BMI.
  
  
  RESULTS
  A total of 131 children were overweight; the prevalence of asthma was 24.4% and 14.2% among overweight and normal-weight children, respectively. Exposure to SHS was significantly associated with asthma among overweight (adjusted odds ratio [adjOR] = 3.0; 95% confidence interval [CI] = 1.2, 7.4) but not normal-weight children (adjOR = 1.1; 95% CI = 0.4, 2.7). In contrast, TRAP was significantly associated with asthma among normal-weight (adjOR = 1.8; 95% CI = 1.0, 3.4) but not overweight children (adjOR = 0.7; 95% CI = 0.4, 2.7).
  
  
  CONCLUSIONS
  The association between SHS and TRAP exposure and asthma is modified by children's weight. Children's time-activity patterns, including time spent indoors or outdoors, may vary by weight and play an important role in these UFP exposures.
authors.affiliation: Department of Environmental Health, University of Cincinnati, Cincinnati, Ohio, USA; Division of Asthma Research, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
authors.forename: Grace
authors.initials: G
authors.lastname: LeMasters
authors.forename: Linda
authors.initials: L
authors.lastname: Levin
authors.forename: David I
authors.initials: DI
authors.lastname: Bernstein
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Lockey
authors.forename: James E
authors.initials: JE
authors.lastname: Lockey
authors.forename: Jeff
authors.initials: J
authors.lastname: Burkle
authors.forename: Gurjit K
authors.initials: GK
authors.lastname: Khurana Hershey
authors.forename: Kelly
authors.initials: K
authors.lastname: Brunst
authors.forename: Patrick H
authors.initials: PH
authors.lastname: Ryan
mesh_terms: D001249:Asthma / Q000453:epidemiology / Q000209:etiology*; D015992:Body Mass Index; D002648:Child; D005260:Female; D006801:Humans; D056865:Ideal Body Weight / Q000502:physiology*; D019570:Inhalation Exposure / Q000009:adverse effects / Q000706:statistics & numerical data; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D050177:Overweight / Q000150:complications* / Q000453:epidemiology; D015995:Prevalence; D012307:Risk Factors; D014028:Tobacco Smoke Pollution / Q000009:adverse effects* / Q000706:statistics & numerical data; D001335:Vehicle Emissions / Q000633:toxicity*
chemical_list: D014028:Tobacco Smoke Pollution; D001335:Vehicle Emissions