[1] Univ Fed Rio de Janeiro, Grad Internal Med Program, Rio De Janeiro, RJ, Brazil
[2] McGill Univ, Resp Epidemiol & Clin Res Unit, Montreal, PQ, Canada
[3] Imperial Coll, Sch Publ Hlth, Dept Primary Care & Publ Hlth, London, England
[4] Univ Estado Rio De Janeiro, Social Med Inst, Rio De Janeiro, RJ, Brazil