Byung Chul Yoon

Seroepidemiological study of Helicobacter pylori infection in asymptomatic people in South Korea

Abstract Background: Helicobacter pylori infection occurs throughout the world and causes gastroduodenal diseases in all age groups. The prevalence of H. pylori infection varies between countries and races. The aim of this study was to evaluate the seroprevalence of H. pylori infection in asymptomatic healthy people in South Korea.

Prevalence of irritable bowel syndrome in Korea: population-based survey using the Rome II criteria.

Background:  Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder in the West. But information on the prevalence of IBS in Asia is still lacking, especially in Korea. Therefore, the aims of the present study were to estimate the prevalence of IBS in the general population of Korea and also to investigate characteristics of IBS and health‐care‐seeking behavior of IBS patients.

A Population-Based Study on Bowel Habits in a Korean Community: Prevalence of Functional Constipation and Self-Reported Constipation

Most studies of bowel habits have been conducted in Western countries. This study was conducted to estimate the epidemiology of constipation and the discrepancy between self-reported constipation and bowel habits in Koreans. Telephone interviews regarding bowel habits were conducted with a total of 1029 individuals in Korea, 15 years of age or older. Subjects were given a questionnaire which asked about bowel symptoms, sociodemographic associations, laxative use, and physician visits. Of all subjects 95.6% had a defecation frequency of between three per week and three per day. The prevalence was 16.5% for self-reported constipation, 9.2% for functional constipation (FC), and 3.9% for constipation-predominant irritable bowel syndrome (IBS-C). Of subjects’ self-reporting constipation, proportions of FC and IBS-C were 21.8% and 23.5%, respectively. Of subjects excluding self-reported constipation, the proportion of FC was 6.8%. Prevalences of self-reported constipation and IBS-C were higher in females than in males (P < 0.001). Of subjects’ self-reporting constipation, 8.2% used laxatives. We conclude that constipation is a common problem in the general Korean population.

Effect of multispecies probiotics on irritable bowel syndrome: A randomized, double-blind, placebo-controlled trial

The efficacy of treatment with multispecies probiotics on irritable bowel syndrome (IBS) symptoms and the alterations of gut microbiota in patients who have taken probiotics were investigated.

The Differences in Prevalence and Sociodemographic Characteristics of Irritable Bowel Syndrome According to Rome II and Rome III.

Background/Aims Irritable bowel syndrome (IBS) is one of the most frequently observed disorders by primary care and practitioners. The aim of this study was to estimate the prevalence of IBS using the Rome II and III criteria in the general Korean population and also to compare sociodemographic differences between subjects diagnosed by these criteria. Methods Telephone interview surveys were performed with a total of 1,009 individuals in Korea, 15 years of age or older. The questionnaire, based on the Rome II and III criteria, was validated. Results Among the 1,009 subjects, the prevalence of IBS was 8.0% under the Rome II criteria (81 subjects; 6.4%, male; 9.6%, female), and 9.0% (91 subjects; 7.0%, male; 11.0%, female) under the Rome III criteria. The accordance rate of Rome II and III was 73.5%. Both groups showed highest frequency in the age of 30s (13.9% vs. 15.3% respectively). Female subjects showed a higher prevalence than male subjects under Rome III (91 subjects; 11.0% in female, 7.0% in male; p < 0.05), but not under Rome II criteria. Many patients older than 50 years were added when analyzed under the Rome III criteria, but not under the Rome II criteria (p = 0.017). Conclusions The Rome III criteria were less restrictive and showed good agreement with the Rome II criteria. The prevalence of IBS was increased in young women.

Caffeine attenuates liver fibrosis via defective adhesion of hepatic stellate cells in cirrhotic model

Several epidemiological studies have shown that coffee intake attenuates the progression of liver fibrosis; however, the mechanism is unclear.

Prevention of free fatty acid-induced hepatic lipotoxicity by carnitine via reversal of mitochondrial dysfunction

Mitochondria are the main sites for fatty acid oxidation and play a central role in lipotoxicity and nonalcoholic steatohepatitis.

Association between GERD-related erosive esophagitis and obesity.

Background and Objectives To date, many studies have reported on the association of obesity with gastroesophageal reflux disease (GERD), although none of these have been systematic. In light of this, we conducted this study to examine the association of obesity and GERD. Subjects and Methods A total of 3363 patients underwent gastroscopy at Hanyang University Health Promotion Center. Among these patients, we prospectively examined patients who were diagnosed with GERD-related erosive esophagitis on endoscopy. Results Multivariate analysis showed that the significant risk factors were waist-to-hip ratio (WHR), hiatal hernia, body mass index (BMI), and smoking. As compared with patients who had a WHR less than 0.8, the multivariate odds ratio for erosive esophagitis were 4.055 for a WHR more than 1.0 and 2.316 for a WHR of 0.8 to 1.0. As compared with patients who had a BMI of 20 to 22.5, the multivariate odds ratio for erosive esophagitis was 3.308 (95% confidence interval, 1.792 to 6.107) for a BMI greater than 30. Conclusions Obesity, especially abdominal obesity, was the significant risk factor for erosive esophagitis.

Association between erosive esophagitis and visceral fat accumulation quantified by abdominal CT scan.

Background and Aims There were no objective data presented about the association between erosive esophagitis and abdominal fat. We conducted this study to examine the association of abdominal fat and gastroesophageal reflux disease-related erosive esophagitis. Methods Between May 2004 and October 2005, a total of 100 erosive esophagitis patients diagnosed by upper endoscopy were evaluated in a prospective manner. All study patients and controls underwent abdominal computed tomography (CT) scan. Body fat distribution was assessed by CT with a 10-mm-thick slice at the level of the fourth lumbar vertebra. Results Erosive esophagitis patients presented with a significantly higher mean visceral fat (VF) area (104.68±39.47 vs. 75.90±49.10 cm2, P=0.014) than the control group. However, there was no association between erosive esophagitis and subcutaneous fat area (109.72±49.09 vs. 98.66±52.43 cm2, P=0.379) or total fat area (214.41±78.78 vs. 172.59±90.49 cm2, P=0.054). Multivariate logistic regression analysis demonstrated that high VF areas (P=0.0035), VF/subcutaneous fat area (P=0.005), hiatal hernia (P=0.001), high body mass index (P=0.047), high waist-to-hip ratio (P=0.042), and smoking (P=0.005) are independent risk factors of erosive esophagitis. Conclusions These results suggest a role for visceral obesity, quantified by CT, as a risk factor for erosive esophagitis.

Analysis of CYP2E1 polymorphism for the determination of genetic susceptibility to gastric cancer in Koreans

Background:  Interindividual genetic differences in susceptibility to chemical carcinogens are among the most important host factors in human cancer. The present study was undertaken to reveal the association between the polymorphism of CYP2E1 (CYP2E1/PstI and CYP2E1/DraI) with genetic susceptibility to gastric cancer development in Koreans.