[1] McMaster Univ, Sch Rehabil Sci, Hamilton, ON, Canada
[2] McMaster Univ, Dept Clin Epidemiol & Biostat, Hamilton, ON, Canada
[3] Canadian Mem Chiropract Coll, Toronto, ON, Canada
[4] NW Hlth Sci Univ, Wolfe Harris Ctr Clin Studies, Bloomington, MN USA
[5] Univ Amsterdam, Acad Med Ctr, Coronel Inst Occupat Hlth, NL-1012 WX Amsterdam, Netherlands
[6] Univ Amsterdam, Acad Med Ctr, Res Ctr Insurance Med, NL-1012 WX Amsterdam, Netherlands