[1] Univ Warwick, Warwick Clin Trials Unit, Div Hlth Sci, Coventry CV4 7AL, W Midlands, England
[2] Univ Aberdeen, Inst Appl Hlth Sci, Epidemiol Grp, Aberdeen, Scotland
[3] Univ Manchester, Sch Psychol Sci, Manchester, Lancs, England
[4] Univ Aberdeen, Inst Appl Hlth Sci, Aberdeen Hlth Psychol Grp, Aberdeen, Scotland
[5] Univ Stirling, Midwifery & Allied Hlth Profess Res Unit, Stirling FK9 4LA, Scotland
[6] Univ Aberdeen, Inst Med Sci, Div Appl Med, Aberdeen, Scotland
[7] Univ Dundee, Ninewells Hosp & Med Sch, Dundee Canc Ctr, Dundee DD1 9SY, Scotland
[8] Univ Aberdeen, Inst Appl Hlth Sci, Aberdeen, Scotland
[9] Aberdeen Royal Infirm, Aberdeen, Scotland
[10] Univ Aberdeen, Inst Appl Hlth Sci, Med Stat Team, Aberdeen, Scotland