1. Department of Epidemiology; Geisel School of Medicine at Dartmouth; Hanover NH U.S.A.
2. Department of Epidemiology; University of North Carolina; Chapel Hill NC U.S.A.
3. Department of Pediatrics; University of Arizona; Tucson AZ U.S.A.
4. Department of Gastroenterology, Hepatology, and Nutrition; University of Texas MD Anderson Cancer Center; Houston TX U.S.A.
5. Epidemiology Division; Dalla Lana School of Public Health; University of Toronto; ON Canada