Table 1—

Characteristics of the study population

COPD casesControl subjects
Subjects n299164231200
 Age yrs65.2±9.462.6±9.055.7±9.554.1±8.9
 Current smokers46.853.737.747.5
  <10 cigarettes·day−110.412.27.816.5
  10–19 cigarettes·day−121.430.521.223.0
  ≥20 cigarettes·day−
 Pack-years30.6 (21–43)22.5 (16–32)18.0 (10–27)14.0 (8–23)
Height cm175.3±6.8163.0±5.9178.2±6.6166.0±5.8
Pre-BD FEV1 % pred49.5±17.449.9±16.491.9±9.193.0±8.9
Post-BD FEV1 % pred52.6±17.453.1±16.194.5±8.896.0±9.1
GOLD classification
 Stage II58.262.8
 Stage III28.128.1
 Stage IV13.79.2
  • Data are presented as mean±sd, per cent or median (25th–75th percentiles), unless otherwise stated. COPD: chronic obstructive pulmonary disease; BD: bronchodilator; FEV1: forced expiratory volume in 1 s; % pred: % predicted; GOLD: Global Initiative for Chronic Obstructive Lung Disease.