1 University of Exeter Medical School, University of Exeter, Exeter, United Kingdom.
2 Department of Medicine, University of California, San Francisco, San Francisco, California.
3 Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, Berkeley, California.
4 University of Michigan, Ann Arbor, Michigan.
5 University of Ferrara, Ferrara, Italy.
6 Weill Cornell Medical Center/New York-Presbyterian Hospital, New York, New York.
7 Hospital Universitario de Caracas Universidad Central de Venezuela Centro Médico de Caracas, Caracas, Venezuela.
8 College of Medicine, University of Lagos, Lagos, Nigeria.
9 Pulmocare Research and Education Foundation, Pune, India.
10 St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada.
11 National Clinical Research Center of Respiratory Disease, Guangzhou Institute of Respiratory Health, First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
12 Respiratory Health, University of Barcelona, Hospital Clinic, IDIBAPS, and CIBERES, Barcelona, Spain; and.