[1] Brigham & Womens Hosp, Dept Med, Div Prevent Med, Boston, MA 02215 USA
[2] Brigham & Womens Hosp, Dept Med, Div Cardiovasc, Boston, MA 02215 USA
[3] Harvard Univ, Sch Med, Boston, MA USA
[4] Harvard Univ, Sch Publ Hlth, Dept Epidemiol, Boston, MA 02115 USA
[5] Vet Affairs Med Ctr, Massachusetts Vet Epidemiol Res & Informat Ctr, Brockton, MA USA