[1] Univ Fed Rio Grande Sul UFRGS, Fac Med, Porto Alegre, RS, Brazil
[2] Univ Fed Rio de Janeiro UFRJ, Fac Med, Inst Doencas Torax, Rio De Janeiro, RJ, Brazil
[3] IRCCS, Ist Clin Scientif Maugeri, Serv Epidemiol Clin Malattie Respiratorie, Tradate, Italy
[4] Queen Mary Univ London, Blizard Inst, London, England
[5] Fundacao Oswaldo Cruz Fiocruz, Ctr Referencia Helio Fraga, Rio De Janeiro, Brazil