Table 1.

The Operational Criteria for Early Chronic Obstructive Pulmonary Disease

Required	One or More of the Following
<50 yr of age	FEV1/FVC less than the lower limit of normal
≥10 pack-years smoking history	Compatible CT abnormalities (visual emphysema, air trapping, or bronchial thickening graded mild or worse)
	Evidence of accelerated FEV1 decline (≥60 ml/yr)

Definition of abbreviaton: CT = computed tomography.

Reproduced from Reference 5.