1. The Chinese University of Hong Kong; Division of Epidemiology, The Jockey Club School of Public Health and Primary Care; Hong Kong SAR China
2. The Chinese University of Hong Kong; Division of Epidemiology, School of Public Health and Primary Care; Prince of Wales Hospital, Shatin Hong Kong China
3. Chronic Airways Diseases Laboratory, Nanfang Hospital, Southern Medical University; Department of Respiratory Medicine; No. 1838, North Guangzhou Avenue Guangzhou Guangdong China 510515