Frequencies of overall airflow limitation, and moderate to very severe airflow limitation in men and women.

Definition of abbreviations: FEV1  =  forced expiratory volume in 1 second; % pFEV1  =  FEV1/predicted FEV1×100%; FVC  =  forced vital capacity; CS  =  current smoker; Ex S  =  ex-smoker; NS  =  never-smoker; *, significantly different from CS (p<0.01); †, significantly different from Ex S (p<0.01).