[1] Harvard Univ, Sch Med, Dept Med, Massachusetts Gen Hosp, Boston, MA USA
[2] NHLBI, Framingham Heart Study, Framingham, MA USA
[3] NHLBI, Populat Res Branch, Div Intramural Res, NIH, Bethesda, MD 20892 USA
[4] Boston Univ, Sch Med, Dept Med, Boston, MA 02118 USA
[5] Boston Univ, Sch Med, Whitaker Cardiovasc Inst, Boston, MA 02118 USA
[6] Vanderbilt Univ, Div Cardiovasc Med, Nashville, TN 37235 USA