[1] Univ N Carolina, Dept Family Med, Sch Med, Chapel Hill, NC 27599 USA
[2] Univ N Carolina, Cecil G Sheps Ctr Hlth Serv Res, Chapel Hill, NC 27599 USA
[3] Univ N Carolina, Lineberger Comprehens Canc Ctr, Chapel Hill, NC 27599 USA
[4] N Carolina State Univ, Dept Psychol, Raleigh, NC 27695 USA
[5] Univ S Australia, Inst Choice, Sydney, NSW, Australia
[6] Univ Sydney, Sch Publ Hlth, Sydney, NSW 2006, Australia
[7] Univ N Carolina, Sch Med, Div Gen Internal Med, Chapel Hill, NC 27599 USA
[8] Univ N Carolina, Ctr Hlth Promot & Dis Prevent, Chapel Hill, NC 27599 USA
[9] Univ Michigan, Dept Med, Ann Arbor, MI 48109 USA
[10] Univ Colorado, Sch Med, Dept Med, Div Gen Internal Med, Aurora, CO USA