Table 1—

Characteristics of the study population

Subjects n311386
Age yrs65.5±8.160.4±8.0<0.001#
Smoking status n (%)<0.001
 Current171 (55.0)205 (53.1)
 Former129 (41.5)128 (33.2)
 Never11 (3.5)53 (13.7)
Smoking pack-yrs+42.6±20.030.8±16.9<0.001
FEV1 % pred63.4±26.3104.9±16.8<0.001
FEV1/FVC %49.7±13.180.7±7.4<0.001
  • Data are presented as mean±sd, unless otherwise stated. All cases and controls were male ethnic Koreans. COPD: chronic obstructive pulmonary disease; FEV1: forced expiratory volume in one second; % pred: % predicted; FVC: forced vital capacity. #: t-test; : Chi-squared test; +: in current and former smokers.