Table 1 Characteristics of the subjects eligible at the ECRHS I and traced at the ECRHS II, divided into three groups according to the presence of airflow obstruction, as defined by the two criteria
Fixed cut-off (70%)Subjects without AO (n = 5664)Misidentified subjects (n = 318)Subjects with AO (n = 267)p Value (misidentified subjects vs those without AO)p Value (misidentified subjects vs those with AO)
Women (%)52.864.239.7<0.001<0.001
Age (years) (%)
Ever smokers56.558.465.90.5210.061
    Median (IQR) No of pack-years*9.5 (4.2–17.7)9.5 (5.0–18.0)15.0 (5.0–27.0)0.3030.004
FEV1% pred (mean (SD))107.1 (12.4)97.0 (11.2)84.7 (16.1)<0.001<0.001
FVC% pred (mean (SD))108.6 (13.0)113.8 (13.3)109.5 (17.3)<0.001<0.001
BHR slope† (mean (SD))7.84 (2.09)6.32 (2.46)5.57 (2.25)<0.0010.007
High total IgE (%)22.931.537.00.0010.178
IgE sensitisation (%)32.542.053.50.0010.008
Chronic cough or phlegm (%)12.117.423.40.0050.075
Physician diagnosed asthma (%)‡13.827.453.9<0.001<0.001
  • All variables were measured at the ECRHS I, unless stated otherwise.

  • *Among ever smokers.

  • †A low slope is indicative of a high BHR; p values were obtained after adjusting for baseline FEV1% predicted.

  • ‡Self-reported diagnosis of asthma during their lifetime at the ECRHS II.

  • AO, airflow obstruction; BHR, bronchial hyperresponsiveness; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; LLN, lower limit of normal.