PLoS ONE (Jan 2012)

Bronchial responsiveness is related to increased exhaled NO (FE(NO)) in non-smokers and decreased FE(NO) in smokers.

  • Andrei Malinovschi,
  • Christer Janson,
  • Marieann Högman,
  • Giovanni Rolla,
  • Kjell Torén,
  • Dan Norbäck,
  • Anna-Carin Olin

DOI
https://doi.org/10.1371/journal.pone.0035725
Journal volume & issue
Vol. 7, no. 4
p. e35725

Abstract

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RationaleBoth atopy and smoking are known to be associated with increased bronchial responsiveness. Fraction of nitric oxide (NO) in the exhaled air (FE(NO)), a marker of airways inflammation, is decreased by smoking and increased by atopy. NO has also a physiological bronchodilating and bronchoprotective role.ObjectivesTo investigate how the relation between FE(NO) and bronchial responsiveness is modulated by atopy and smoking habits.MethodsExhaled NO measurements and methacholine challenge were performed in 468 subjects from the random sample of three European Community Respiratory Health Survey II centers: Turin (Italy), Gothenburg and Uppsala (both Sweden). Atopy status was defined by using specific IgE measurements while smoking status was questionnaire-assessed.Main resultsIncreased bronchial responsiveness was associated with increased FE(NO) levels in non-smokers (p = 0.02) and decreased FE(NO) levels in current smokers (p = 0.03). The negative association between bronchial responsiveness and FE(NO) was seen only in the group smoking less ConclusionsThe present study highlights the interactions of the relationship between FE(NO) and bronchial responsiveness with smoking and atopy, suggesting different mechanisms behind atopy- and smoking-related increases of bronchial responsiveness.