Table S1.

List of definitions

Definitions
Airway obstruction	FEV1/FVC ratio <0.70
BD reversibility test	ERS/ATS recommendations: ”Significant” BD response was defined as an increase in FEV1 of minimum 0.200 L and 12% of pre-BD FEV1 after administration of a short-acting β2 agonist30
Corticosteroid reversibility test	Six weeks of treatment with inhaled corticosteroid or 14 days of oral steroid followed by repeat spirometry. An increase in FEV1 of >0.200 L was considered a positive test
COPD	Spirometric defined according to GOLD recommendations 2014: Post-BD FEV1/FVC ratio <0.7016
GOLD severity of airway obstruction	FEV1 % predicted:
GOLD 1: mild	≥80%
GOLD 2: moderate	50%≤ FEV1 <80%
GOLD 3: severe	30%≤ FEV1 <50%
GOLD 4: very severe	<30%
Asthma	Increase in FEV1 >0.500 L at the BD reversibility test or >0.200–0.500 L with additional 0.200 L increase on the corticosteroid reversibility test

Abbreviations: ATS, American Thoracic Society; BD, bronchodilator; COPD, chronic obstructive pulmonary disease; ERS, European Respiratory Society; FEV₁, forced expiratory volume in one second; FVC, forced vital capacity; GOLD, Global Initiative for Chronic Obstructive Lung Disease.