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
Overall100018.18.30.10
Age yrs
 40–4933814.14.10.84
 50–5929686.57.2<0.01
 60–69217211.211.50.57
 ≥70148015.915.70.73
Smoking history
 Never-smoker42914.04.01.0
 0–10 pack-yrs17775.04.80.66
 10–20 pack-yrs12709.69.61.0
 ≥20 pack-yrs265416.317.10.01
Sex
 Male47669.19.10.90
 Female52357.27.60.01
Site
 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.