Figure 1
From: Genetic susceptibility for chronic bronchitis in chronic obstructive pulmonary disease
Genome-wide association study design for chronic bronchitis. Definition of abbreviations: CB = chronic bronchitis; COPD = chronic obstructive pulmonary disease; GOLD = Global initiative for chronic Obstructive Lung Disease. GOLD 2-4 was defined as having a post-bronchodilator FEV1/FVC < 0.7 and FEV1 < 80% predicted. Normal spirometry was defined as having a post-bronchodilator FEV1/FVC ≥ 0.7 and FEV1 ≥ 80% predicted.