[1] Univ Vermont, Dept Med Biostat, Dept Math & Stat, Burlington, VT 05405 USA
[2] Univ Vermont, Vermont Reg Canc Ctr, Burlington, VT 05405 USA
[3] Univ Vermont, Off Hlth Promot Res, Florida Evaluat Off, Ft Myers, FL 33907 USA
[4] Univ Vermont, Off Hlth Promot Res, Dept Family Practice, Burlington, VT 05405 USA
[5] Vanderbilt Univ, Vanderbilt Med Ctr, Div Gen Internal Med, Nashville, TN USA