[1] Aarhus Univ, Sch Publ Hlth, Dept Epidemiol, Aarhus, Denmark
[2] Randers Cent Hosp, Inst Pathol, Randers, Denmark
[3] Aarhus Univ Hosp, Dept Neurol, DK-8000 Aarhus, Denmark
[4] Sch Publ Hlth, Dept Gen Practice, Aarhus, Denmark
[5] Univ Calif Los Angeles, Sch Publ Hlth, Dept Epidemiol, Los Angeles, CA 90024 USA