[1] Univ Leicester, Dept Hlth Sci, Ctr Biostat & Genet Epidemiol, Leicester LE1 6TP, Leics, England
[2] Univ Leicester, Dept Cardiovasc Sci, Cardiol Grp, Glenfield Hosp, Leicester, Leics, England
[3] F Hoffmann La Roche & Co Ltd, Roche Genet, Div Pharmaceut, CH-4070 Basel, Switzerland