BACKGROUND Prospective nationwide multicentre studies that have evaluated endoscopic findings and reflux symptoms using a well-designed questionnaire are very rare.

AIM To compare the prevalence rates of and risk factors for erosive oesophagitis and non-erosive reflux disease (NERD) in the Korean population.

METHODS A gastroscopic examination was performed on 25 536 subjects who visited 40 Healthcare Centers for a health check-up. A gastro-oesophageal reflux questionnaire and multivariate analysis were used to determine the risk factors for erosive oesophagitis and NERD.

RESULTS 2019 (8%) and 996 subjects (4%) had erosive oesophagitis and non-erosive reflux disease, respectively; only 58% of subjects with erosive oesophagitis had reflux symptoms. Multivariate analysis showed that the risk factors for erosive oesophagitis and NERD differed, i.e. those of erosive oesophagitis were male, a Helicobacter pylori eradication history, alcohol, body mass index > or =25 and hiatal hernia. In contrast, the risk factors for NERD were female, age <40 and > or =60 vs. 40-59 years, body mass index <23 and a monthly income <$1000, glucose > or =126 mg/dL, smoking, a stooping posture at work and antibiotic usage.

CONCLUSIONS The prevalence rates of erosive oesophagitis and NERD were 8% and 4%, respectively, in Korean health check-up subjects. The risk factors for erosive oesophagitis and NERD were found to differ, which indicates that their underlying pathogeneses are distinct.