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Clinical and Translational Medicine

Table 1 Study participant distribution according to the GOLD standards

From: Biomarkers of early chronic obstructive pulmonary disease (COPD) in smokers and former smokers. Protocol of a longitudinal study

Study groups by pack years and air flow limitation

Pack years 1 pack year = 20 cigarettes a day in 1 year

Airflow limitation FEV1/FVC < 70 %

Healthy never smokers n = 50

0

No

Healthy smokers/ex-smokers n = 25

<20

No

At risk smokers/ex-smokers n = 25

>20

No

GOLD stage 1 smokers/ex-smokers n = 75

>20

FEV1 ≥ 80 %

GOLD stage 2 smokers/ex-smokers n = 75

>20

50 % ≤ FEV1 < 80 %

GOLD stage 3 smokers/ex-smokers n = 25

>20

30 % ≤ FEV1 < 50 %

GOLD stage 4 smokers/ex-smokers n = 25

>20

FEV1 < 30 %

  1. The enrolled subjects will be divided in the following study groups. The total number of participants will be 300, including 50 healthy never smokers, 25 healthy smokers and ex-smokers, 25 at risk smokers and ex-smokers, 200 participants with GOLD stage 1–4 divided in 75 with GOLD stage 1 and 2 respectively (smokers and ex-smokers) and 25 with GOLD stage 3 and 4 respectively COPD participants (smokers and ex-smokers)
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