[1] Univ Nebraska Med Ctr, Coll Nursing, Lincoln, NE USA
[2] Mayo Clin, Dept Cardiovasc Med, Div Prevent Cardiol, Coll Med, Rochester, MN USA
[3] Stanford Sch Med, Dept Epidemiol & Populat Hlth, Dept Med Div Primary Care & Populat Hlth, Palo Alto, CA 94304 USA