Lung Diseases, Obstructive

• Research Site — Loma Linda, California, United States
• Research Site — Long Beach, California, United States
• Research Site — Roseville, California, United States
• Research Site — Aurora, Colorado, United States

• Alsadd Pediatric Emergency Center — Doha, Qatar

• ACES Entre Douro e Vouga II- Aveiro Norte — Oliveira de Azeméis, Aveiro District, Portugal

• Soroka University Medical Center — Beersheba, South, Israel

• Odense University Hospital — Odense, Denmark

• Research Site — Baotou, China
• Research Site — Beijing, China
• Research Site — Beijing, China
• Research Site — Beijing, China

Not specified

• Hasan Kalyoncu University — Gaziantep, Turkey (Türkiye)

• University of North Carolina at Chapel Hill — Chapel Hill, North Carolina, United States
• Wake Forest University Baptist Medical Center — Winston-Salem, North Carolina, United States

• National Heart & Lung Institue Clinical Studies Unit, Imperial College London — London, United Kingdom