[1] UNIV UTAH, SCH MED, DEPT PEDIAT, SALT LAKE CITY, UT USA
[2] MINNESOTA DEPT HLTH, MINNESOTA PUBL HLTH LAB, MINNEAPOLIS, MN 55414 USA
[3] MAYO CLIN, DEPT PEDIAT, ROCHESTER, MN USA
[4] UNIV MINNESOTA, SCH MED, DEPT PEDIAT, MINNEAPOLIS, MN 55455 USA
[5] UNIV MINNESOTA, SCH MED, DEPT SURG, MINNEAPOLIS, MN 55455 USA