[1] Russells Hall Hosp, Dudley Grp Hosp, NHS Fdn Trust Teaching, Dept Rheumatol,Clin Res Unit, Dudley DY1 2HQ, W Midlands, England
[2] UCL, Sch Med, Dept Clin Biochem, Vasc Prevent Clin,Royal Free Hosp, London W1N 8AA, England
[3] Univ Manchester, Arthrit Res Campaign Epidemiol Unit, Manchester, Lancs, England