Table A1 Screening criteria used to determine the respiratory status of subjects
Respiratory symptomsWheezing, dyspnoea, cough (⩾3 months/year) or an asthma attack or shortness of breath due to an allergic reaction (in the previous 12 months)
Lung function below the normal rangeFEV1/VC ⩽ lower limit of normal (predicted −1.64 SD)
ReversibilityFEV1 reversibility ⩾15% predicted
(at least two out of three) mild early signsFEV1/VC ⩽ predicted value minus 1 SD and/or
FEV1 reversibility ⩾10% predicted and/or
weather dependent (productive) cough or shortness of breath or the occurrence of more than one period of (productive) cough in the previous two years
  • FEV1, forced expiratory volume in 1 s; VC, vital capacity.