[1] Univ Minnesota, Sch Med, Div Endocrinol & Diabet, Minneapolis, MN 55455 USA
[2] Univ Minnesota, Dept Biostat, Minneapolis, MN 55455 USA
[3] Univ Washington, Sch Med, Seattle, WA USA
[4] Univ Minnesota, Gen Clin Res Ctr, Minneapolis, MN 55455 USA
[5] Univ Washington, Gen Clin Res Ctr, Seattle, WA 98195 USA