[1] Stanford Univ, Stanford Ctr Hlth Policy, Ctr Primary Care & Outcomes Res, Stanford, CA 94305 USA
[2] Stanford Univ, Sch Med, Stanford, CA 94305 USA
[3] Stanford Univ, Stanford Prevent Res Ctr, Stanford, CA 94305 USA
[4] Stanford Univ, Sch Humanities & Sci, Stanford, CA 94305 USA
[5] Palo Alto Med Fdn, Res Inst, Palo Alto, CA 94301 USA