[1] Univ Cambridge, Dept Med, Cambridge CB2 2QQ, England
[2] Univ Cambridge, Dept Clin Biochem, Cambridge CB2 2QQ, England
[3] Univ Cambridge, Dept Publ Hlth & Primary Care, Cambridge CB2 2QQ, England
[4] AstraZeneca Pharmaceut, CVGI Discovery, Macclesfield, Cheshire, England