TABLE 3.
Prevalence of chronic obstructive pulmonary disease (COPD) computed using FEV1/FEV6 in place of FEV1/FVC
| Subjects n | COPD criterion |
p-value# | ||
|---|---|---|---|---|
| LLN (FEV1/FEV6) and FEV1 <80% pred |
LLN (FEV1/FVC) and FEV1 <80% pred |
|||
| Overall | 10001 | 8.1 | 8.3 | 0.10 |
| Age yrs | ||||
| 40–49 | 3381 | 4.1 | 4.1 | 0.84 |
| 50–59 | 2968 | 6.5 | 7.2 | <0.01 |
| 60–69 | 2172 | 11.2 | 11.5 | 0.57 |
| ≥70 | 1480 | 15.9 | 15.7 | 0.73 |
| Smoking history | ||||
| Never-smoker | 4291 | 4.0 | 4.0 | 1.0 |
| 0–10 pack-yrs | 1777 | 5.0 | 4.8 | 0.66 |
| 10–20 pack-yrs | 1270 | 9.6 | 9.6 | 1.0 |
| ≥20 pack-yrs | 2654 | 16.3 | 17.1 | 0.01 |
| Sex | ||||
| Male | 4766 | 9.1 | 9.1 | 0.90 |
| Female | 5235 | 7.2 | 7.6 | 0.01 |
| Site | ||||
| Guangzhou, China | 473 | 6.8 | 5.5 | 0.03 |
| Adana, Turkey | 806 | 8.3 | 9.3 | 0.04 |
| Salzburg, Austria | 1258 | 7.2 | 7.5 | 0.34 |
| Cape Town, South Africa | 847 | 17.1 | 16.3 | 0.25 |
| Reykjavik, Iceland | 757 | 5.9 | 6.5 | 0.29 |
| Hanover, Germany | 683 | 5.1 | 5.0 | 1.0 |
| Krakow, Poland | 526 | 7.6 | 7.4 | 1.0 |
| Bergen, Norway | 658 | 5.9 | 6.8 | 0.11 |
| Vancouver, BC, Canada | 827 | 5.7 | 6.4 | 0.07 |
| Lexington, KY, USA | 508 | 11.2 | 12.4 | 0.15 |
| Manila, Philippines | 893 | 9.2 | 8.4 | 0.09 |
| Sydney, Australia | 541 | 8.1 | 7.6 | 0.38 |
| London, UK | 677 | 9.2 | 10.2 | 0.02 |
| Uppsala, Sweden | 547 | 4.9 | 5.7 | 0.12 |
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.