Table 1—

Characteristics of the general population weighted sample

Patients n862533329
Age yrs
 High school or University42.548.865.3
 Primary school or no education56.751.234.7
Social class (occupations)#
 I–II (professional/intermediate)
 III (skilled nonmanual)32.030.733.2
IV–V (manual)49.840.153.7
Smoking behaviour
 Never smoker52.725.478.3
 Former Smoker24.141.57.8
 Smoker>20 pack-yrs13.124.12.9
 Smoker⩽20 pack-yrs10.09.010.9
Respiratory diseases
Spirometric results
 FVC mL3454.5±877.74024.7±795.52916.9±552.2
 FEV1 mL2578.6±726.42959.5±762.82219.5±459.7
 % FVC over pred90.3±13.887.0±13.893.5±13.1
 % FEV1 over pred89.5±16.584.9±17.893.7±13.8
 FEV1/FVC %99.2±11.196.6±12.0101.6±9.4
  • Data are presented as % or mean±sd unless otherwise stated

  • M: male

  • F: female

  • COPD: chronic obstructive pulmonary disease

  • FVC: forced vital capacity

  • FEV1: forced expiratory volume in one second

  • #: social class based on an adaptation of the British General's Classification 26