1. Section of GastroenterologySacramento Veteran Affairs Medical CenterVeteran Affairs Northern California Health Care System (VANCHCS)MatherCAUSA
2. Division of Gastroenterology and HepatologyUniversity of CaliforniaDavis School of MedicineSacramentoCAUSA
3. Department of GastroenterologyXijing Hospital of Digestive DiseasesFourth Military Medical UniversityXi'anShaanxiChina
4. Clinical and Translational Science CenterDepartment of Public Health SciencesDivision of BiostatisticsUniversity of California, DavisSacramentoCAUSA
5. Sepulveda Ambulatory Care CenterVeteran Affairs Greater Los Angeles Healthcare System (VAGLAHS) and David Geffen School of Medicine at UCLANorth HillsCAUSA