1. From the Department of Preventive Medicine, Northwestern University, Feinberg School of Medicine, Chicago, IL (B.S., A.C.M., L.A.C., J.S., M.R., M.L.D., K.L.); Department of Radiology, Tufts University School of Medicine, Boston, MA (J.F.P.); Division of Cardiovascular Sciences, National Heart, Lung, and Blood Institute, Bethesda, MD (J.P.R.); and Division of Research, Kaiser Permanente Northern California, Oakland, CA (S.S.).