The medical history and physical examination of the participants were collected by the full-time doctors in the outpatient or ward of the department of gastroenterology, and the general conditions of the paticipants were recorded in detail, including name, gender, age, medical history, smoking and drinking history, etc. The total amount of alcohol consumed per week was calculated and classified into three grades: nondrinkers, light drinkers(< 70 g/week), or moderate drinkers (7–210 g/week for male and 70–140 g/week for female) and defined nondrinkers as did not drink any alcohol in the past 12 months [21].