[1] NHLBI, Framingham Heart Study, Framingham, MA 01702 USA
[2] Northwestern Univ, Feinberg Sch Med, Div Cardiol, Chicago, IL USA
[3] Northwestern Univ, Dept Prevent Med, Chicago, IL USA
[4] Boston Univ, Dept Epidemiol & Prevent Med, Stat & Consulting Unit, Boston, MA 02215 USA
[5] Boston Univ, Sch Med, Gen Internal Med Sect, Boston, MA 02118 USA
[6] Harvard Univ, Massachusetts Gen Hosp, Sch Med, Div Cardiol, Boston, MA USA
[7] NHLBI, Bethesda, MD 20892 USA