[1] Univ N Carolina, Sch Med, Ctr Esophageal Dis & Swallowing, UNC CH, Chapel Hill, NC 27599 USA
[2] Univ N Carolina, Sch Med, Dept Med, UNC CH, Chapel Hill, NC 27599 USA
[3] Univ N Carolina, Sch Med, Dept Epidemiol, UNC CH, Chapel Hill, NC 27599 USA
[4] Univ N Carolina, Sch Publ Hlth, Dept Epidemiol, UNC CH, Chapel Hill, NC 27599 USA
[5] Univ N Carolina, Sch Publ Hlth, Dept Med, UNC CH, Chapel Hill, NC 27599 USA
[6] Univ N Carolina, Sch Med, Ctr Esophageal Dis & Swallowing, Div Gastroenterol & Hepatol, Chapel Hill, NC 27599 USA