[1] McGill Univ, Res Inst, Ctr Hlth, Div Clin Epidemiol,Dept Med, Montreal, PQ H3A 1A1, Canada
[2] McGill Univ, Dept Med, Ctr Hlth, Div Rheumatol, Montreal, PQ H3A 1A1, Canada
[3] McGill Univ, Ctr Hlth, Div Gen Internal Med, Dept Med, Montreal, PQ H3A 1A1, Canada
[4] McGill Univ, Ctr Hlth, Div Allergy & Clin Immunol, Dept Med, Montreal, PQ H3A 1A1, Canada