Age | n | FEV1/FVC <0.70 | FEV1/FVC <LLN | FEV1/FVC <LLN and FEV1 <80%pred | ||||
GOLD | NHANES III | HSE | NL | NHANES III | HSE | NL | ||
Dutch | ||||||||
<50 | 2965 | 12.2 | 17.2 | 20.7 | 11.1 | 4.6 | 5.2 | 4.4 |
⩾50 | 1592 | 36.1 | 26.6 | 29.3 | 14.6 | 15.5 | 14.9 | 9.9 |
All | 4557 | 20.5 | 20.4 | 23.7 | 12.3 | 8.4 | 8.6 | 6.3 |
English | ||||||||
<50 | 14 506 | 6.0 | 9.2 | 11.8 | 6.7 | 2.4 | 2.4 | 2.6 |
⩾50 | 10 098 | 24.0 | 15.7 | 17.3 | 9.1 | 14.2 | 13.5 | 6.7 |
All | 24 604 | 13.4 | 11.9 | 14.1 | 7.7 | 7.2 | 6.9 | 4.3 |
American | ||||||||
<50 | 3196 | 6.3 | 10.2 | 12.4 | 6.9 | 2.7 | 2.8 | 4.4 |
⩾50 | 3633 | 35.5 | 20.2 | 21.4 | 10.2 | 16.8 | 15.1 | 7.8 |
All | 6829 | 21.8 | 15.5 | 17.2 | 8.7 | 10.2 | 9.4 | 5.8 |
Different definitions of airway obstruction include: the GOLD criterion; FEV1/FVC below the LLN for three reference equations; and the last three columns apply the FEV1% pred <80% (BTS and NICE) criteria together with the FEV1/FVC <LLN criteria for each reference equation.
The most appropriate reference equations are internal to the study (indicated by the bold numbers). Analysis in Americans was limited to Caucasian subjects. Reference equation sources: NHANES III26 and HSE.20 NL is the Dutch reference equations (see appendix in the online data supplement).
BTS, British Thoracic Society; FEV1/FVC, forced expiratory volume in 1 s/forced vital capacity; GOLD, Global Initiative for Chronic Obstructive Lung Disease; HSE, Health Survey for England; LLN, lower limit of normal; NICE, National Institute for Health and Clinical Excellence; NHANES III, National Health and Nutrition Examination Survey III.