[1] Univ Utah, Huntsman Canc Inst, Canc Control & Populat Sci, Salt Lake City, UT USA
[2] Univ Utah, Sch Med, Dept Surg, Salt Lake City, UT USA
[3] Brigham Young Univ, Dept Econ, Provo, UT 84602 USA
[4] Univ Utah, Sch Med, Dept Populat Hlth Sci, Salt Lake City, UT USA
[5] Univ Utah, Sch Med, Dept Family & Prevent Med, Salt Lake City, UT USA
[6] Univ Utah, Sch Med, Dept Pediat, Salt Lake City, UT USA
[7] Univ Washington, Dept Epidemiol, Seattle, WA 98195 USA