[1] Univ Cambridge, Dept Publ Hlth & Primary Care, Primary Care Unit, Cambridge, England
[2] Univ Cambridge, Sch Clin Med, Cambridge, England
[3] Univ Cambridge, Ctr Canc Genet Epidemiol, Dept Publ Hlth & Primary Care, Cambridge, England
[4] Univ Cambridge, PHG Fdn, Cambridge, England
[5] Univ Cambridge, Dept Surg, Cambridge, England
[6] Univ Cambridge, Dept Publ Hlth & Primary Care, Primary Care Unit, East Forvie Bldg, Cambridge CB2 0SR, England