[1] Univ Minnesota, Div Epidemiol, Minneapolis, MN 55454 USA
[2] St Paul Heart Clin, St Paul, MN USA
[3] Penn State Univ, Milton S Hershey Med Ctr, Dept Hlth Evaluat Serv, Hershey, PA 17033 USA
[4] Wake Forest Univ, Bowman Gray Sch Med, Dept Publ Hlth Sci, Winston Salem, NC 27103 USA
[5] Univ N Carolina, Sch Publ Hlth, Dept Epidemiol, Chapel Hill, NC USA
[6] Univ N Carolina, Dept Biostat, Collaborat Studies Coordinating Ctr, Chapel Hill, NC USA
[7] NHLBI, NIH, Bethesda, MD 20892 USA