Table 3—

Prevalence of chronic obstructive pulmonary disease(COPD) computed using FEV1/FEV6 in place of FEV1/FVC

Subjects nCOPD criterionp-value#
LLN (FEV1/FEV6) and FEV1 <80% predLLN (FEV1/FVC) and FEV1 <80% pred
Age yrs
Smoking history
 0–10 pack-yrs17775.04.80.66
 10–20 pack-yrs12709.69.61.0
 ≥20 pack-yrs265416.317.10.01
 Guangzhou, China4736.85.50.03
 Adana, Turkey8068.39.30.04
 Salzburg, Austria12587.27.50.34
 Cape Town, South Africa84717.116.30.25
 Reykjavik, Iceland7575.96.50.29
 Hanover, Germany6835.15.01.0
 Krakow, Poland5267.67.41.0
 Bergen, Norway6585.96.80.11
 Vancouver, BC, Canada8275.76.40.07
 Lexington, KY, USA50811.212.40.15
 Manila, Philippines8939.28.40.09
 Sydney, Australia5418.17.60.38
 London, UK6779.210.20.02
 Uppsala, Sweden5474.95.70.12
  • Data are presented as %, unless otherwise stated. Prevalence data are univariate classifications and not adjusted for other terms in the table. FEV1: forced expiratory volume in 1 s; FEV6: forced expiratory volume in 6 s; FVC: forced vital capacity; LLN: lower limit of normal; % pred: % predicted. #: two-tailed exact p-values based on McNemar's test for comparing prevalences within each subgroup.