230 T. Takashima et al. examination by nursing staffs, and to assess clinical charac- teristics of patients reflux esophagitis without any symptoms by this process. Materials and Methods Patients This study re-analyzed, focused on symptoms detection by nursing stuff, data detected in the previous study [8], and the recruited method described briefly as follows: Patients were recruited from 23 hospitals, including the Saga Medical School, in Saga Prefecture (population, ~800,000), and were not randomly selected community samples as in our previous studies [8]. A total of 8031 Japanese patients (4120 male, 3911 female; aged >30 years, mean 59.4) were enrolled in the present multicenter study from September 1996 to October 1998. Among the 8031 patients, 6166 were outpatients who visited the 23 hospitals but did not receive medication for gastrointestinal disease, and the other 1865 were mainly selected from those receiving secondary examinations from a primary gastroenterological mass survey conducted in Saga Prefecture (50000/year), or patients who visited the hospitals for a routine physical examination. The study was conducted according to the provisions of the Declaration of Helsinki. The clinical study committee of Saga Medical School Hospital approved the study, and all patients were informed about the basic concept of the present study and of gastrointestinal endoscopy. Patients were excluded if they had received medication for gastro- intestinal disease, or had had laparotomy. Patients who had had a major psychotic episode, mental retardation or dementia were also excluded. Symptoms assessment Before endoscopic examination, each patient was inter- viewed by nursing staffs who briefly asked questions regarding current clinical symptoms, including heartburn, dysphagia, odynophagia (chest pain or irritation on swal- lowing) and acid regurgitation. The patients simply answered “yes” or “no”. Endoscopists were blinded to the interview results before their evaluation of reflux esophagitis. Upper gastrointestinal endoscopy Upper gastrointestinal endoscopy for evaluation of reflux esophagitis was performed by experienced endoscopists, certified by the Japan Gastroenterological Endoscopy Society. The endoscopists were directed to grade esophageal mucosal breaks with esophagitis according to the Los Angeles Classification of Esophagitis in 1996 [2]. To reduce interobserver variation in the grading of esophagitis, pre- testing and several meetings were held before this study was conducted. The criteria for the diagnosis of esophagitis were: grade A, one or more mucosal breaks, each no longer than 5 mm; grade B, at least one mucosal break more than 5 mm long; grade C, at least one mucosal break, continuous between the tops of two or more mucosal folds; grade D, circumferential mucosal break. The endoscopists were also required to check for upper gastrointestinal diseases such as gastric and/or duodenal ulcers, polyps and cancer, but dis- orders other than esophagitis were not evaluated in this study. Statistical analysis We analyzed data from endoscopy-positive patients who did not complain of symptoms. Most of the analyses gave rise to contingency tables by the χ2 test of independence and the Cochran–Mantel–Haenzel method. We used a logistic regression model to compute the odds ratio (OR) and the 95% confidence interval (CI) in multivariate modeling. Age, sex and other symptoms were adjusted to calculate the OR. Two-tailed p values <0.05 were considered significant. Statistical analyses were performed with the SAS statistical package (version 6.08; SAS Inc., Cary, NC). Results Esophagitis was found in 1199/8031 (14.9%) patients. The grade of reflux esophagitis was evaluated by endoscopy, as follows: grade A, 717 (8.9%) patients; grade B, 341 (4.2%); and grade C + D, 141 (1.8%). Heartburn was the most common symptom of reflux esophagitis and was found in 539 of 1199 (45.0%) endoscopy-positive patients. Four hundred and sixty-five of 1199 (38.8%) of endoscopy- positive patients did not complain of any symptoms. The clinical characteristics of Group I (esophagitis with heart- burn) and Group II (esophagitis without any symptoms) were compared. As indicated in Table 1, the number of males was significantly higher in Group II compared to Group I. Body mass index (BMI) was significantly higher in Group I than in Group II. The rate of hiatus hernia was high in Group I, and endoscopic esophagitis was significantly more severe in Group I compared to Group II. Other factors including age, smoking and alcohol consumption did not differ between the two groups. Univariate analysis of clinical characteristics of patients in Groups I and II is shown in Table 2. This indicated that gender, BMI, hiatus hernia, and severity of reflux were closely related to the presence or absence of clinical symptoms of endoscopic reflux esophagitis. Results of multivariate analysis are shown in Table 3. As indicated, male gender, absence of hiatus hernia, patients not over- weight, and absence of severe reflux esophagitis (grades C and D) were clinical characteristics of Group II patients compared to Group I. J. Clin. Biochem. Nutr.