Background/AimsGastroesophageal reflux disease (GERD) is increasing in Asian countries. Functional dyspepsia (FD) or irritable bowel syndrome (IBS) are also prevalent and commonly overlapped with GERD. This study was conducted to compare the proportion and risk factors for overlapping reflux esophagitis (RE) and non-erosive reflux disease (NERD) with functional gastrointestinal disorders (FGIDs).MethodsA total of 2,388 [male, 55.9%; mean age (± SD), 43.2 years (± 8.4)] Korean subjects who underwent the upper endoscopy for health screening were prospectively included. The subjects were asked about demographic, medical and social history by using a structured questionnaire, and FD and IBS were assessed according to the Rome III criteria.ResultsThe subjects with RE were 286 (12.0%, male 88.5%, 42.8 years) and 74 subjects had NERD (3.1%) while the prevalence of FD and IBS were 8.1% and 10.1%, respectively. The proportion of FD and IBS in NERD was higher than that of RE (74.3% vs. 10.5%, p = 0.000; 41.9% vs. 11.2%, p = 0.000, respectively). The epigastric pain syndrome (EPS) was more prevalent than postprandial distress syndrome in NERD. According to multiple regression analysis, high somatization score and the presence of FD increased the odd ratio for NERD. However, male gender and current smoker were significant risk factors for RE.ConclusionsCompared to RE, NERD is more frequently overlapped with FD, especially EPS, and also are associated with significantly increased frequency of IBS. Our data draws attention to the possibility of subgrouping FGIDs and GERD to be important in understanding the pathophysiology of these conditions.