[1] NHLBI, Framingham Heart Study, Framingham, MA 01702 USA
[2] Inst Clin Evaluat Sci, Toronto, ON, Canada
[3] Univ Toronto, Univ Hlth Network, Toronto, ON, Canada
[4] Boston Univ, Dept Math & Stat, Boston, MA 02215 USA
[5] Boston Univ, Sch Med, Cardiol Sect, Boston, MA 02118 USA
[6] Boston Univ, Sch Med, Dept Prevent Med & Epidemiol, Boston, MA 02118 USA
[7] Harvard Univ, Massachusetts Gen Hosp, Sch Med, Div Cardiol, Boston, MA USA
[8] Univ Toronto, Sunnybrook Hlth Sci Ctr, Toronto, ON, Canada
[9] NHLBI, Ctr Populat Studies, Bethesda, MD 20892 USA