1. Specialist Trainee in Public Health,
2. Chadburn Clinical Lecturer in Primary Care Research,
3. Statistical Advisor, Catchon, The Barn, Farnham Road, Surrey GU10 5BB, UK;
4. Senior Clinical Lecturer in Primary Care, Department of Health Sciences, University of Leicester, Leicester General Hospital, Leicester LE5 4PW, UK;
5. Director of Research, Department of Family Medicine, Medical University of South Carolina, 295 Calhoun St, Charleston, SC 29425, USA
6. Professor of Primary Care, Department of Primary Care and Social Medicine, Imperial College, Reynolds Building, St Dunstan's Road, London W6 8RP, UK;