[1] Brigham & Womens Hosp, Div Prevent Med, Boston, MA 02215 USA
[2] Boston Univ, Sch Med, Dept Med, Boston, MA 02215 USA
[3] Boston Univ, Sch Med, Whitaker Cardiovasc Inst, Boston, MA 02215 USA
[4] Harvard Univ, Sch Publ Hlth, Dept Epidemiol, Cambridge, MA 02138 USA
[5] Vet Affairs Med Ctr, Massachussets Vet Epidemiol Res & Informat Ctr, Boston, MA USA
[6] Harvard Univ, Sch Med, Dept Ambulatory Care & Prevent, Boston, MA 02115 USA