1. Department of Pediatrics , Beijing Friendship Hospital, Capital Medical University , Beijing , China
2. Department of Clinical Epidemiology and EBM , Beijing Friendship Hospital, Capital Medical University , Beijing , China
3. Clinical Research Center for Digestive Diseases , Beijing Friendship Hospital, Capital Medical University , Beijing , China
4. Beijing Hong Jian Medical Device Company , Beijing , China
5. Department of Pediatrics , Chinese PLA General Hospital , Beijing , China