[1] Vet Affairs Med Ctr, Dept Med, W Roxbury, MA 02132 USA
[2] Massachusetts Vet Epidemiol Res Informat Ctr, W Roxbury, MA USA
[3] Harvard Med Sch, Boston, MA USA
[4] Brigham & Womens Hosp, Div Prevent Med, Dept Med, Boston, MA 02115 USA
[5] Brigham & Womens Hosp, Div Cardiovasc, Dept Med, Boston, MA 02115 USA