[1] Univ Tromso, Dept Clin Med, Hematol Res Grp, N-9037 Tromso, Norway
[2] Univ Hosp N Norway, Div Internal Med, Tromso, Norway
[3] Univ Tromso, Dept Clin Med, Brain & Circulat Res Grp, N-9037 Tromso, Norway
[4] Univ Hosp N Norway, Dept Neurol & Clin Neurophysiol, Tromso, Norway
[5] Univ Tromso, Dept Community Med, Tromso, Norway
[6] Leiden Univ, Dept Clin Epidemiol, Med Ctr, Leiden, Netherlands
[7] Leiden Univ, Dept Thrombosis & Haemostasis, Med Ctr, Leiden, Netherlands