Joint association of cigarette smoking and PM2.5 with COPD among urban and rural adults in regional China

Cigarette smoking and PM2.5 are important risk factors of Chronic Obstructive Pulmonary Disease (COPD). However, the joint association of cigarette smoking and PM2.5 with COPD is unknown. Methods: A community-based study was conducted among urban and rural adults aged 40+years between May and December of 2015 in Jiangsu Province, China.