title: An evaluation of the use of bronchoconstriction induced by deep inspiration as a new epidemiological measure for asthma.
abstract: BACKGROUND
  Bronchoconstriction after deep inhalation is associated with increased severity of asthma and is also a predictor of length of hospital stay in individuals admitted with asthma exacerbations. We hypothesized that this effect may represent a new non-invasive method to assess bronchial reactivity and other measures of asthma control.
  
  
  METHODS
  We used a cross-sectional study design recruiting participants 18 to 65 years of age with a physician diagnosis of asthma. All participants were asked to provide three serial peak expiratory flow rate (PEFR) measurements in the morning, and bronchial reactivity was measured up to a maximum inhaled dose of 24.5 micromoL methacholine on the same day. Participants also recorded their asthma symptoms score and bronchodilator use during the 7 days before measuring bronchial reactivity.
  
  
  RESULTS
  A total of 127 people provided data for analysis. There was no significant relationship between bronchoconstriction after deep inhalation (as measured by three serial PEFR measurements) and either bronchial reactivity to methacholine, asthma symptoms, or bronchodilator use.
  
  
  CONCLUSIONS
  Bronchoconstriction induced by deep inspiration does not appear to be a valid marker of airway hyperresponsiveness or asthma severity in adults with mild to moderate asthma.
authors.affiliation: Division of Epidemiology and Public Health, University of Nottingham, Clinical Sciences Building, City Hospital, Nottingham, UK. Zara.Hoare@nottingham.ac.uk
authors.forename: Zara E K
authors.initials: ZE
authors.lastname: Pogson
authors.forename: Tricia M
authors.initials: TM
authors.lastname: McKeever
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Lewis
authors.forename: John R
authors.initials: JR
authors.lastname: Britton
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Fogarty
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001249:Asthma / Q000175:diagnosis* / Q000453:epidemiology*; D015415:Biomarkers; D016535:Bronchial Hyperreactivity / Q000139:chemically induced / Q000453:epidemiology*; D001985:Bronchial Provocation Tests; D016084:Bronchoconstriction / Q000187:drug effects* / Q000502:physiology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015994:Incidence; D001239:Inhalation / Q000187:drug effects; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D016210:Methacholine Chloride; D008875:Middle Aged; D010366:Peak Expiratory Flow Rate / Q000187:drug effects; D011336:Probability; D012042:Registries; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D015415:Biomarkers; D016210:Methacholine Chloride