title: Overweight is associated with airflow obstruction and poor disease control but not with exhaled nitric oxide change in an asthmatic population.
abstract: BACKGROUND
  The role of an elevated body mass index (BMI) in asthma remains controversial.
  
  
  OBJECTIVE
  To investigate the relationship between overweight (BMI >25 and ≤30), lung function, disease control, and airway inflammation in an asthmatic population.
  
  
  METHODS
  We consecutively studied 348 patients (age 43 ± 16 years; 211 females). In all patients, BMI, spirometry, the Asthma Control Test (ACT), and fractional exhaled nitric oxide (FeNO; ppb) were measured.
  
  
  RESULTS
  One hundred forty-five patients were overweight and, as compared to those with normal BMI, had lower values of FVC, FEV(1), and FEV(1)/FVC and of FEF(25-75) even when normalized for FVC (p < 0.05 for each comparison). The ratio between the number of patients with well-controlled asthma (ACT ≥20) and that of patients with poorly controlled asthma (ACT < 20) was significantly lower in overweight patients (1.07 vs. 1.84; χ(2) = 6.030, p < 0.01). In overweight patients, the odds ratio of uncontrolled asthma expressed by logistic regression analysis was 1.632 (95% CI = 1.043-2.553), independently of gender, atopy, smoking habit, and inhaled steroid therapy. No difference was observed in FeNO values between overweight and normal weight patients (27.7 ± 2.3 vs. 27.9 ± 2.2 ppb).
  
  
  CONCLUSIONS
  Our results show that, in an asthmatic population, overweight is associated with airflow obstruction and poor disease control but not with FeNO change. The findings of the present study support the view that other factors besides airway inflammation alone may explain the relationship between asthma and an elevated BMI.
authors.affiliation: Clinical & Experimental Medicine Department, Respiratory Disease Unit, University Hospital of Parma, Parma, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Pisi
authors.forename: Marina
authors.initials: M
authors.lastname: Aiello
authors.forename: Panagiota
authors.initials: P
authors.lastname: Tzani
authors.forename: Emilio
authors.initials: E
authors.lastname: Marangio
authors.forename: Dario
authors.initials: D
authors.lastname: Olivieri
authors.forename: Giovanna
authors.initials: G
authors.lastname: Pisi
authors.forename: Alfredo
authors.initials: A
authors.lastname: Chetta
mesh_terms: D000328:Adult; D001249:Asthma / Q000453:epidemiology / Q000503:physiopathology; D015992:Body Mass Index; D001944:Breath Tests; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000032:analysis; D050177:Overweight / Q000453:epidemiology / Q000503:physiopathology; D012044:Regression Analysis; D013147:Spirometry
chemical_list: D009569:Nitric Oxide