Accommodation in a refugee shelter as a risk factor for peptic ulcer bleeding after the Great East Japan Earthquake: a case–control study of 329 patients

Background We have reported that the total number of peptic ulcers (PUs) had increased 1.5-fold after the Great East Japan Earthquake compared with those of the previous year, and that hemorrhagic ulcers were more prominently increased by 2.2-fold. The aim of this study is to determine the risk factors for bleeding ulcers after the Great East Japan Earthquake.