["The prevalence of reflux esophagitis, which might lead to development of Barrett's esophagus and esophageal adenocarcinoma, has been increasing. The aim of this study was to assess risk factors for reflux esophagitis.", 'We conducted a cross-sectional study of 1,495 Japanese subjects undergoing health checkups (822 males and 673 females; median age 50 years) at a tertiary care center.', 'One hundred and twenty-seven subjects (8%) had reflux esophagitis and hiatal hernia was observed in 292 subjects (20%). Reflux esophagitis (13 vs. 3%) and hiatal hernia (28 vs. 9%) were more frequent in males than females. Significant differences in clinical backgrounds were observed between females and males. Multivariate logistic regression analyses revealed that hiatal hernia (OR 6.63, 95% CI 2.47-17.8; p = 0.0002) was associated with reflux esophagitis in females. In males, age (per 1-year increment: OR 0.96, 95% CI 0.94-0.99; p = 0.007), hiatal hernia (OR 3.16, 95% CI 2.05-4.87; p < 0.0001) and waist circumference (per 1-cm increase: OR 1.09, 95% CI 1.02-1.15; p = 0.006) were associated with reflux esophagitis.'] Is large waist circumference a risk factor for reflux esophagitis in Japanese males?