[1] Univ Utah, Hlth Sci Ctr, Dept Gastroenterol, Salt Lake City, UT 84132 USA
[2] Univ Utah, Hlth Sci Ctr, Dept Biostat Family & Preventat Med, Salt Lake City, UT 84132 USA
[3] Univ Utah, Hlth Sci Ctr, Dept Dermatol, Salt Lake City, UT 84132 USA
[4] Univ Utah, Hlth Sci Ctr, Dept Pathol, Salt Lake City, UT 84132 USA