[1] Univ Fed Rio Grande Sul, Hosp Clin Porto Alegre, Div Cardiol, Serv Cardiol, BR-90035003 Porto Alegre, RS, Brazil
[2] Univ N Carolina, Sch Publ Hlth, Dept Epidemiol, Chapel Hill, NC USA
[3] Univ N Carolina, Sch Publ Hlth, Dept Biostat, Chapel Hill, NC USA
[4] Tulane Univ, Med Ctr, Sch Publ Hlth & Trop Med, New Orleans, LA 70112 USA
[5] Johns Hopkins Univ, Sch Hyg & Publ Hlth, Dept Epidemiol, Baltimore, MD USA
[6] Johns Hopkins Univ, Welch Ctr Prevent Epidemiol & Clin Res, Baltimore, MD USA