[1] Northwestern Univ, Evanston, IL 60208 USA
[2] Univ Pittsburgh, Pittsburgh, PA USA
[3] Univ N Carolina, Chapel Hill, NC 27515 USA
[4] Virginia Commonwealth Univ, Richmond, VA USA
[5] Univ Michigan, Ann Arbor, MI 48109 USA
[6] Ohio State Univ, Columbus, OH 43210 USA
[7] Vanderbilt Univ, 221 Kirkland Hall, Nashville, TN 37235 USA
[8] Univ Utah, Salt Lake City, UT USA
[9] Univ Kentucky, Lexington, KY USA
[10] AcademyHealth, Washington, DC USA
[11] Univ Wisconsin, Madison, WI USA
[12] Univ Wisconsin, Sch Med & Publ Hlth, Dept Populat Hlth Sci, Madison, WI USA
[13] Univ Pittsburgh, Sch Med, Dept Med, Pittsburgh, PA 15213 USA
[14] Univ Pittsburgh, Sch Publ Hlth, Dept Hlth Policy & Management, Pittsburgh, PA 15260 USA
[15] Univ Pittsburgh, Sch Publ Hlth, Dept Biostat, Pittsburgh, PA 15260 USA