[1] MCGILL UNIV,DEPT EPIDEMIOL & BIOSTAT,MONTREAL,PQ,CANADA
[2] MCGILL UNIV,DEPT FAMILY MED,MONTREAL,PQ H3A 2T5,CANADA
[3] ST MARYS HOSP,DEPT CLIN EPIDEMIOL & COMMUNITY STUDIES,MONTREAL,PQ,CANADA
[4] ST MARYS HOSP,DEPT FAMILY MED,MONTREAL,PQ,CANADA
[5] ST MARYS HOSP,DEPT REHABIL,MONTREAL,PQ,CANADA