Purpose: Bile and acid exposures are thought to be major risk factors for Barrett's esophagus in Western countries. The association of gallstones with Barrett's esophagus has not been fully evaluated. The present study was designed as a case-control study for determining the possible factors associated with endoscopically suspected esophageal metaplasia (ESEM), defined as an endoscopic finding suggestive of Barrett's esophagus, in Japanese patients. Methods: A total of 528 patients with ESEM were allocated to the case group, while 528 age- and gender-matched patients without ESEM were allocated to the control group. Findings on esophagogastroduodenoscopy and clinical background factors were compared using a multivariate logistic regression model. Results: The presence of gallstones and hiatus hernia and the severity of gastric mucosal atrophy were independently associated with the presence of ESEM [odds ratio (OR) 1.67, 95% confidence interval (CI) 1.03-2.69; OR 2.75, 95% CI 1.75-4.33; OR 1.25, 95% CI 1.01-5.6, respectively]. Compared with subjects with neither gastric corpus atrophy nor gallstones, although subjects with gallstones alone were not associated with the presence of ESEM (OR 1.59, 95% CI 0.87-2.92), having both gastric corpus atrophy and gallstones was strongly associated with the presence of ESEM (OR 2.94, 95% CI 1.40-6.17). Conclusions: The presence of gallstones was independently associated with the presence of ESEM in the Japanese outpatient population, suggesting a causal association of distal esophageal bile exposure with the development of ESEM. Further studies are needed to confirm our findings in cases with histologically confirmed Barrett's esophagus.
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