[1] Framingham Heart Dis Epidemiol Study, Framingham, MA USA
[2] Beth Israel Deaconess Med Ctr, Dept Med, Div Cardiovasc, Boston, MA 02215 USA
[3] Harvard Univ, Sch Med, Boston, MA USA
[4] Boston Univ, Sch Med, Sect Cardiol & Preventat Med, Boston, MA 02118 USA
[5] Boston Univ, Sch Publ Hlth, Dept Epidemiol, Boston, MA USA