[1] Univ Liverpool, Liverpool, Merseyside, England
[2] Newcastle Univ, Newcastle Upon Tyne, Tyne & Wear, England
[3] Univ Edinburgh, Edinburgh, Midlothian, Scotland
[4] Univ Oxford, Oxford, England
[5] MRC Clin Trials Unit UCL, London, England
[6] Univ Nottingham, Nottingham, England
[7] Queens Univ, Belfast, Antrim, North Ireland