1. Genetic Epidemiology Group; Department of Epidemiology & Public Health; Division of Population Health; University College London; London WC1E 6BT UK
2. Department of Pharmacy; Royal National Orthopaedic Hospital; Middlesex HA7 4LP UK
3. Department of Pharmacy; University College London Hospital; London NW1 2BU UK
4. Centre for Clinical Pharmacology; University College London; London WC1E 6JF UK
5. Faculty of Epidemiology and Population Health; London School of Hygiene and Tropical Medicine; London WC1E 7HT UK
6. School of Pharmacy; University of Hertfordshire; Hatfield AL10 9AB UK
7. Health Economics Research Group; Brunel University; Middlesex UB8 3PH UK