1. Cancer Epidemiology Unit, Nuffield Department of Population Health; University of Oxford; Headington Oxford United Kingdom
2. Department of Epidemiology and Evaluation; Hospital del Mar; Barcelona Spain
3. IMIM (Hospital del Mar Medical Research Institute); Barcelona Spain
4. REDISSEC; Health Services Research on Chronic Patients Network; Madrid Spain
5. Prince of Wales Clinical School; UNSW Australia; Sydney NSW Australia