Pulmonary Disease, Chronic Obstructive

• Georgia Prevention Institute — Augusta, Georgia, United States

• University of Colorado Hospital — Aurora, Colorado, United States

• Landspitali National University Hospital — Reykjavik, Ísland, Iceland

• Kindai University Faculty of Medicine — Ōsaka-sayama, Osaka, Japan

• Respiratory and Allergy Research Unit, Department of Respiratory Medicine L, Bispebjerg Hospital — Copenhagen, Denmark

• Columbia University — New York, United States

• University of Southampton — Southampton, United Kingdom

Not specified

• Research Site — Llanelli, United Kingdom
• Research Site — Merthyr Tydfil, United Kingdom

• Research Site — Erpent, Belgium
• Research Site — Eindhoven, Netherlands
• Research Site — Groningen, Netherlands
• Research Site — Zutphen, Netherlands