Raw data behind the results of this study

The main data are provided for 900 subjects who completed the study (500 smokers, 200 ex-smokers, and 200 never-smokers). Missing data were not replaced. Subject ID (ID), study group, gender, age, ethnicity, education, cigarette consumption (expressed as a number of pack-year), regular secondary smoking in past 12 months (for ex- and never-smokers), airflow obstruction by spirometry (FEV1/FVC < 70%), Six minute walk test, CAT total score, CAT components: - cough; - phlegm; - tightness of chest; - shortness of breath (SOB); - limited doing activities at home; - not confident leaving home; - not sleeping soundly; - no energy, metabolic syndrome (1 – yes, 0 – no), central obesity (1 – yes, 0 – no), raised triglyceride (≥ 150 mg/dL: 1 – yes, 0 – no), reduced high-density lipoprotein (< 40 mg/dL for males and < 50 mg/dL for females: 1 – yes, 0 – no), raised blood pressure (≥130/85 mm Hg: 1 – yes, 0 – no), raised fasting plasma glucose (≥ 100 mg/dL: 1 – yes, 0 – no).