1. Cochrane Central Executive; Review Production and Quality Unit, Editorial & Methods Department; St Albans House, 57-59 Haymarket London England UK SW1Y 4QX
2. Lancaster University; Medical School; Lancaster UK
3. Lancashire Care NHS Foundation Trust; Sceptre Point, Sceptre Way Walton Summit Preston UK PR5 6AW
4. St George's University Hospitals NHS Foundation Trust; Chest Unit; London UK
5. Cardiff University; Department of Child Health, The Division of Population Medicine, The School of Medicine; Cardiff UK