1. Department of Primary Care and Public Health (C.J.C., C.D.P., C.Ll.M.), School of Medicine, Cardiff University
2. Department of Global Epidemiology (C.J.C., C.D.P., C.Ll.M.), Pharmatelligence, Cardiff CF14 4UJ, United Kingdom
3. Department of Medicine (M.E., J.R.P.), University Hospital of Wales, Cardiff CF14 4XW, United Kingdom