[1] Thai Red Cross Soc, King Chulalongkorn Mem Hosp, Div Gastroenterol, Dept Med, Bangkok, Thailand
[2] Chulalongkorn Univ, Div Pulm & Crit Care Med, Dept Med, Fac Med, Bangkok, Thailand
[3] Chulalongkorn Univ, Fac Med, Ctr Excellence Neurogastroenterol & Motil, Bangkok, Thailand
[4] Thai Red Cross Soc, King Chulalongkorn Mem Hosp, Excellence Ctr Sleep Disorders, Bangkok, Thailand