COPD	Chronic Obstructive Pulmonary Disease
COPD-S	Chronic Obstructive Pulmonary Disease related to tobacco smoking
COPD-BB	Chronic Obstructive Pulmonary Disease related to biomass burning smoke
SWOC	Smokers without COPD
BBES	Biomass burning exposed subjects
BEI	Biomass exposure index
GOLD	Global Initiative for Chronic Obstructive Lung Disease
SNP	Single Nucleotide Polymorphism
MAF	Minor allele frequency
SERPINA1	Serpin family A member 1
PiS	Protease inhibitor S
PiZ	Protease inhibitor Z
AAT	Alpha-1 antitrypsin
AATd	Alpha-1 antitrypsin deficiency
FE	Frequent exacerbators
NEX	Non-exacerbators
FEV1	Forced expiratory volume in the first second
FVC	Forced vital capacity