title: Effect modification by race-ethnicity of environmental tobacco smoke exposure on airway inflammation in US children.
abstract: BACKGROUND
  Asthma mortality and morbidity are higher in black than in white children. Fractional exhaled nitric oxide (FeNO) is a noninvasive biomarker of eosinophilic airway inflammation. Identification of differences in the effect of environmental tobacco smoke (ETS) on airway inflammation by race and ethnicity from a large sample is needed.
  
  
  OBJECTIVE
  To estimate a racial difference in association with ETS and FeNO.
  
  
  METHODS
  Data from the 2007 to 2012 National Health and Nutrition Examination Survey were analyzed to compare associations of ETS and FeNO levels in US black and other children. No ETS exposure was defined as a serum cotinine level lower than 0.05 ng/mL and ETS exposure was defined as a serum cotinine level of at least 0.05 ng/mL. FeNO was measured using a device that relies on an electrochemical sensor. Analyses took the complex survey design into account.
  
  
  RESULTS
  The analytic sample was formed by 5,473 participants (6-11 years old, n = 2,385; 12-19 years old, n = 3,088) with complete data on demographics, serum cotinine levels, and 2 reproducible FeNO measurements. In weighted linear regression analyses at 6 to 11 years, the interaction term for ETS and black race was not significant (P = .15). At 12 to 19 years, the interaction term was significant (P = .03) in an analysis of all racial groups. In race-specific models, the coefficient for ETS exposure in blacks was -0.033 and that in others was -0.175, ie, ETS exposure was associated with a greater decrease in FeNO in non-blacks than in blacks.
  
  
  CONCLUSIONS
  There was no evidence at 6 to 11 years of age for an effect modification by race of the association between ETS and FeNO. At 12 to 19 years, the data suggested an effect modification.
authors.affiliation: Department of Internal Medicine, Howard University College of Medicine, Washington, DC; Division of Pulmonary Diseases, Howard University College of Medicine, Washington, DC. Electronic address: alem.mehari@howard.edu.
authors.forename: Alem
authors.initials: A
authors.lastname: Mehari
authors.affiliation: Department of Internal Medicine, Howard University College of Medicine, Washington, DC.
authors.forename: Ngozi
authors.initials: N
authors.lastname: Enwerem
authors.affiliation: Department of Internal Medicine, Howard University College of Medicine, Washington, DC; Division of Pulmonary Diseases, Howard University College of Medicine, Washington, DC.
authors.forename: Yewande
authors.initials: Y
authors.lastname: Odeyemi
authors.affiliation: Department of Internal Medicine, Howard University College of Medicine, Washington, DC.
authors.forename: Richard F
authors.initials: RF
authors.lastname: Gillum
mesh_terms: D000293:Adolescent; D015415:Biomarkers / Q000378:metabolism; D002648:Child; D005006:Ethnicity; D005260:Female; D006801:Humans; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D009749:Nutrition Surveys; D011657:Pulmonary Eosinophilia / Q000175:diagnosis / Q000453:epidemiology* / Q000378:metabolism; D044469:Racial Groups; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*; D014481:United States; D055815:Young Adult
chemical_list: D015415:Biomarkers; D014028:Tobacco Smoke Pollution; D009569:Nitric Oxide