title: Decreased fraction of exhaled nitric oxide in obese subjects with asthma symptoms: data from the population study INTERGENE/ADONIX.
abstract: BACKGROUND
  Several studies have demonstrated an association between obesity and asthma. However, it is uncertain if fraction of exhaled nitric oxide (Feno), which is used as a marker of airway inflammation, and atopy are associated with BMI. The aim of this study was to examine if obese subjects with asthma symptoms have a different phenotype of asthma than nonobese subjects as indicated by Feno.
  
  
  METHODS
  The subjects (N = 2,187) consisted of women and men, aged 25 to 74, living in Gothenburg, Sweden, who participated in the randomly selected INTERGENE study cohort. Measurements included anthropometric measures, bioelectric impedance, Feno, pulmonary function, and blood samples for IgE; questionnaires included items on respiratory symptoms. Obesity was defined as BMI ≥ 30 kg/m(2). In this cross-sectional analysis, general linear models were used to analyze how Feno was associated with anthropometry, body composition, wheezing, and atopy.
  
  
  RESULTS
  In nonobese subjects, wheezing was associated with raised Feno and atopy, whereas in contrast, obese subjects who reported wheezing had lower Feno than obese subjects without wheezing (16.1 vs 19.1 parts per billion, P < .01). The prevalence of atopy was similar in both of those subgroups (25.0% vs 20.7%, P = .4). Similarly, in 395 subjects (19%) who reported wheezing, Feno was negatively associated with BMI, waist-to-hip ratio, and percentage of body fat, whereas no significant relationships were observed in those without respiratory symptoms.
  
  
  CONCLUSIONS
  Wheezing was significantly associated with reduced Feno in obese subjects, whereas there was a positive association between wheezing and Feno among the nonobese subjects, indicating a possible difference in asthma phenotype, based on body weight.
authors.affiliation: Department of Food and Nutrition, and Sport Science, University of Gothenburg, Gothenburg, Sweden. Electronic address: christina.berg@ped.gu.se.
authors.forename: Christina M
authors.initials: CM
authors.lastname: Berg
authors.affiliation: Department of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy, Gothenburg, Sweden; Department of Biostatistics, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
authors.forename: Dag S
authors.initials: DS
authors.lastname: Thelle
authors.affiliation: Department of Emergency and Cardiovascular Medicine, Institute of Medicine, Sahlgrenska Academy, Gothenburg, Sweden.
authors.forename: Annika
authors.initials: A
authors.lastname: Rosengren
authors.affiliation: Department of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy, Gothenburg, Sweden.
authors.forename: Lauren
authors.initials: L
authors.lastname: Lissner
authors.affiliation: Department of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy, Gothenburg, Sweden.
authors.forename: Kjell
authors.initials: K
authors.lastname: Torén
authors.affiliation: Department of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy, Gothenburg, Sweden.
authors.forename: Anna-Carin
authors.initials: AC
authors.lastname: Olin
mesh_terms: D000328:Adult; D000368:Aged; D001249:Asthma / Q000150:complications* / Q000378:metabolism*; D015331:Cohort Studies; D045853:Exhalation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism*; D009765:Obesity / Q000150:complications* / Q000378:metabolism*
chemical_list: D009569:Nitric Oxide