1. 1Department of Preventive Medicine and Environmental Health, University of Kentucky College of Public Health,
Lexington, Ky, USA
2. 2Department of Pulmonary, Critical Care, and Sleep Medicine, University of Kentucky College of Medicine,
Lexington, Ky, USA
3. 3GlaxoSmithKline Research and Development, Worldwide Epidemiology,
Middlesex, UK
4. 4GlaxoSmithKline Research and Development, Respiratory Therapy Area Unit,
King of Prussia, PA, USA