[1] Univ Kelaniya, Fac Med, Dept Paediat, Thalagolla Rd, Ragama 11010, Sri Lanka
[2] Univ Kelaniya, Fac Med, Dept Physiol, Thalagolla Rd, Ragama 11010, Sri Lanka
[3] Asiri Hosp, Kirula Rd, Colombo 10100, Sri Lanka
[4] Acad Med Ctr, Emma Childrens Hosp, Dept Paediat Gastroenterol & Nutr, NL-1105 AZ Amsterdam, Netherlands