[1] WELLESLEY COLL HOSP, DEPT MED, DIV RHEUMATOL, TORONTO M4Y 1J3, ONTARIO, CANADA
[2] MAYO CLIN & MAYO FDN, DEPT MED, DIV RHEUMATOL, ROCHESTER, MN 55905 USA
[3] MCMASTER UNIV, DEPT CLIN EPIDEMIOL & BIOSTAT, HAMILTON L8S 4L8, ONTARIO, CANADA
[4] WELLESLEY COLL HOSP, CLIN EPIDEMIOL UNIT, TORONTO M4Y 1J3, ONTARIO, CANADA