[1] NHLBI, Div Epidemiol & Clin Applicat, Epidemiol & Biometry Program, Bethesda, MD 20892 USA
[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] Univ Texas, Hlth Sci Ctr, Genet Ctr, Houston, TX USA
[5] Univ Minnesota, Sch Publ Hlth, Div Epidemiol, Minneapolis, MN 55455 USA
[6] Landeskrankenanstalten, Dept Lab Med, Salzburg, Austria