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Featured researches published by Kum Hei Ryu.


Gastroenterology | 2010

Abdominal Visceral Adipose Tissue Volume Is Associated With Increased Risk of Erosive Esophagitis in Men and Women

Su Youn Nam; Il Ju Choi; Kum Hei Ryu; Bum Joon Park; Hyun Bum Kim; Byung-Ho Nam

BACKGROUND & AIMS Data on the association between erosive esophagitis and obesity are inconsistent because of variations in study populations and methods used to determine obesity. METHODS Participants in a prospective health-screening cohort underwent esophagogastroduodenoscopy and computed tomography. The association between erosive esophagitis and obesity (measured by body mass index [BMI], waist circumference, and abdominal visceral adipose tissue volume) was estimated with odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for confounding factors. We also analyzed the association between obesity and erosive esophagitis by sex. RESULTS The prevalence of erosive esophagitis was 9.3% (495/5329). The OR for erosive esophagitis correlated with obesity measured by BMI, waist circumference, and abdominal visceral adipose tissue volume (P < .001 for each factor). The multivariate OR for erosive esophagitis was 1.97 (95% CI: 1.34-2.90) for a visceral adipose tissue volume of 500-999 cm(3), 2.27 (95% CI: 1.51-3.39) for 1000-1499 cm(3), and 2.94 (95% CI: 1.87-4.62) for ≥1500 cm(3), compared with participants who had visceral adipose tissue volumes less than 500 cm(3). When measures of obesity were analyzed simultaneously, abdominal visceral adipose tissue volume, but not BMI or waist circumference, was associated with erosive esophagitis. The 3 measures of obesity were significantly associated with erosive esophagitis in males, but only visceral adipose tissue volume was associated with erosive esophagitis in females (P = .002). CONCLUSIONS In contrast to BMI or waist circumference, abdominal visceral adipose tissue volume is associated with an increased risk of erosive esophagitis in males and females.


Clinical Gastroenterology and Hepatology | 2010

Abdominal Visceral Adipose Tissue Predicts Risk of Colorectal Adenoma in Both Sexes

Su Youn Nam; Byung Chang Kim; Kyung Su Han; Kum Hei Ryu; Bum Jun Park; Hyun Bum Kim; Byung-Ho Nam

BACKGROUND & AIMS Small studies have shown inconsistent results regarding the association between abdominal visceral adipose tissue and colorectal adenomas. We evaluated the effects of visceral adipose tissue volume on the development and growth of colorectal adenomas. METHODS A total of 3922 participants underwent colonoscopy and computed tomography from February to November 2008. The associations between waist circumference, visceral adipose tissue volume, and colorectal adenomas were estimated with adjusted odds ratios and 95% confidence intervals (CIs). In addition, the association between characteristics of colorectal adenomas and visceral adipose tissue volume was evaluated. RESULTS Compared with participants who had visceral adipose tissue volume of less than 500 cm(3), the odds ratio for colorectal adenoma was 1.09 (95% CI, 0.87-1.36) for a volume of 500 to 999 cm(3), 1.33 (95% CI, 1.04-1.69) for a volume of 1000 to 1499 cm(3), and 1.43 (95% CI, 1.06-1.94) for a volume of 1500 cm(3) or greater. The risk of colorectal adenomas increased with increasing visceral adipose tissue volume in both sexes (P trend = .004 in men and .009 in women). Waist circumference was associated with colorectal adenomas in men (P trend = .02), but not in women. High volume of visceral adipose tissue (>or=1000 cm(3)) had a positive association with larger adenomas (>or=10 mm) and multiple adenomas. CONCLUSIONS Abdominal visceral adipose tissue volume can contribute to the development and growth of colorectal adenomas, and it was a better predictor for risk of colorectal adenomas than body mass index or waist circumference in both sexes.


The American Journal of Gastroenterology | 2010

Effect of Helicobacter pylori Infection and Its Eradication on Reflux Esophagitis and Reflux Symptoms

Su Youn Nam; Il Ju Choi; Kum Hei Ryu; Byung Chang Kim; Chan Gyoo Kim; Byung-Ho Nam

OBJECTIVES:We evaluated the association between current Helicobacter pylori infection and reflux esophagitis and the effect of H. pylori eradication on reflux esophagitis in a healthy screening population.METHODS:A total of 10,102 subjects in a comprehensive screening cohort were enrolled, and 4,007 subjects had follow-up after a median of 2 years. Effects of H. pylori infection on reflux esophagitis were estimated with odds ratios (ORs) and 95% confidence intervals (CIs) using multiple logistic regression analysis. We evaluated the change in prevalence of reflux esophagitis and reflux symptoms after H. pylori eradication vs. persistence.RESULTS:The prevalence of reflux esophagitis (as classified by the Los Angeles system) was 4.9% (490/10,102). Whereas the prevalence of reflux esophagitis was 6.4% (319/4,971) in subjects without H. pylori infection, it was 3.3% (171/5,131) in subjects with infection (P<0.001). H. pylori infection had a strong negative association with reflux esophagitis in multivariate analysis (OR 0.42; 95% CI, 0.34–0.51). Compared with the prevalence of reflux esophagitis in the persistent infection group, the prevalence of reflux esophagitis increased after successful H. pylori eradication (OR 2.34; 95% CI, 1.45–3.76; P<0.001), which was comparable to that of the H. pylori-negative group (OR 2.42; 95% CI, 1.73–3.36; P<0.001). However, reflux symptoms had no association with H. pylori infection or eradication.CONCLUSIONS:In a healthy screening population, H. pylori infection had a strong negative association with reflux esophagitis, but H. pylori eradication increased the prevalence of erosive esophagitis to the level of H. pylori-negative individuals. Long-term clinical significance of newly developed erosive esophagitis after H. pylori eradication should be evaluated prospectively.


Journal of Neurogastroenterology and Motility | 2010

Prevalence and Risk Factors of Irritable Bowel Syndrome in Healthy Screenee Undergoing Colonoscopy and Laboratory Tests

Su Youn Nam; Byung Chang Kim; Kum Hei Ryu; Bum Joon Park

Introduction The prevalence of irritable bowel syndrome (IBS) after excluding organic disease has not been reported in Korea. Methods Of 5,605 participants in a health screening program, inclusion criteria were persons who underwent colonoscopy and completed questionnaires. Exclusion criteria were persons diagnosed with colon cancer, inflammatory bowel disease, previous colectomy, and abnormal results of thyroid function tests. IBS was defined by Rome III criteria. Physical and psychological stress was evaluated with visual analogue scales, ranging from 0 to 10. Risk factors for IBS were estimated with odds ratios (OR) and 95% confidence intervals (CI) using logistic regression analysis. Results The prevalence of IBS was 8.2% (5,605) in the total population and 9.1% (393/4,296) in the final study sample. IBS had a positive association with female sex (adjusted OR, 1.33; 95% CI, 1.00-1.79; p = 0.05) and current smoking (adjusted OR, 1.31; 95% CI, 1.00-1.71; p = 0.05). The prevalence of IBS increased with increased psychological stress (adjusted p for trend = 0.005) and decreased with increasing age (adjusted p for trend <0.001), with adjusted OR of 0.95 (95% CI, 0.68-1.33) for age of 40.0 to 49.9 years; 0.79 (95% CI, 0.54-1.15) for age of 50.0 to 59.9 years; and 0.51 (95% CI, 0.30-0.86) for age of 60 years or more, compared with age less than 40 years. Drinking status, body mass index, hypertension, diabetes, and use of sedatives had no association with IBS. Conclusions The prevalence of IBS increased with decreasing age and increasing psychological stress, and was positively associated with female sex and current smoking.


The Korean Journal of Internal Medicine | 2008

Antibiotic-Associated Diarrhea: Candidate Organisms other than Clostridium Difficile

Hyun Joo Song; Ki Nam Shim; Sung Ae Jung; Hee Jung Choi; Mi Ae Lee; Kum Hei Ryu; Seong Eun Kim; Kwon Yoo

Backgraound/Aims The direct toxic effects of antibiotics on the intestine can alter digestive functions and cause pathogenic bacterial overgrowth leading to antibiotic-associated diarrhea (AAD). Clostridium Difficile (C. Difficile) is widely known to be responsible for 10~20% of AAD cases. However, Klebsiella oxytoca, Clostridium perfringens, Staphylococcus aureus, and Candida species might also contribute to AAD. Methods We prospectively analyzed the organisms in stool and colon tissue cultures with a C. Difficile toxin A assay in patients with AAD between May and December 2005. In addition, we performed the C. Difficile toxin A assays using an enzyme-linked fluorescent assay technique. Patients were enrolled who had diarrhea with more than three stools per day for at least 2 days after the initiation of antibiotic treatment for up to 6~8 weeks after antibiotic discontinuation. Results Among 38 patients (mean age 59±18 years, M:F=18:20), the organism isolation rates were 28.9% (11/38) for stool culture, 18.4% (7/38) for colon tissue cultures and 13.2% (5/38) for the C. Difficile toxin A assay. The overall rate of identification of organisms was 50.0% (19/38). Of the five patients that had a positive result by the C. Difficile toxin A assay, two had no organism isolated by the stool or colon tissue culture. The organisms isolated from the stool cultures were C. Difficile (4), Klebsiella pneumoniae (K. pneumoniae) (3), Candida species (3), and Staphylococcus aureus (1). C. Difficile (4) and K. pneumoniae (3) were isolated from the colon tissue culture. Conclusions For C. Difficile negative AAD patients, K. pneumoniae, Candida species, and Staphylococcus aureus were found to be potential causative organisms.


Helicobacter | 2015

Effects of Helicobacter pylori infection and its eradication on lipid profiles and cardiovascular diseases.

Su Youn Nam; Kum Hei Ryu; Bum Joon Park; Sohee Park

We aimed to examine the relationship of current Helicobacter pylori infection with lipid profile and cardiovascular disease and its eradication effect.


Journal of Neurogastroenterology and Motility | 2015

The Effect of Abdominal Visceral Fat, Circulating Inflammatory Cytokines, and Leptin Levels on Reflux Esophagitis

Su Youn Nam; Il Ju Choi; Kum Hei Ryu; Bum Joon Park; Young-Woo Kim; Hyun Beom Kim; Jeongseon Kim

Background/Aims Although adipocytes secrete inflammatory cytokines and adipokines, their role in reflux esophagitis is controversial. We investigated the association between visceral fat and inflammatory cytokines or adipokines in reflux esophagitis. Methods Abdominal visceral fat and cytokines were measured in 66 individuals with reflux esophagitis and 66 age- and sex-matched controls. The mean values for visceral fat and cytokines were compared in cases and controls. Second, correlations between visceral fat and inflammatory cytokines were measured. Finally, multiple logistic regression models for odds ratios (ORs) and 95% confidence intervals (CIs) were used to estimate the effects of visceral fat and cytokines on reflux esophagitis. Results Visceral fat, leptin, interleukin (IL)-6, and IL-1β were higher in reflux esophagitis compared to controls. Visceral fat showed a strong positive correlation with IL-6 (r = 0.523, P < 0.001), IL-8 (r = 0.395, P < 0.001), and IL-1β (r = 0.557, P < 0.001), and a negative correlation with adiponectin (r = −0.466, P < 0.001). With adjusted analysis, visceral fat/100 (OR, 4.32; 95% CI, 2.18–8.58; P < 0.001) and leptin (OR, 1.36; 95% CI, 1.10–1.69; P = 0.005) independently increased the risk of reflux esophagitis, but the effects of other cytokines were abolished. Conclusions Visceral fat may increase the risk of reflux esophagitis by increasing the levels of inflammatory cytokines. Leptin showed a positive association with reflux esophagitis that was independent of visceral fat.


Helicobacter | 2010

Risk Factors Associated with Gastric Cancer in Patients with a Duodenal Ulcer

Soo-Jeong Cho; Il Ju Choi; Chan Gyoo Kim; Myeong-Cherl Kook; Jong Yeul Lee; Byung Chang Kim; Kum Hei Ryu; Su Youn Nam; Young-Woo Kim

Background:  Although gastric cancer (GC) and duodenal ulcer (DU) are both strongly associated with Helicobacter pylori infection, a DU is negatively associated with the risk of GC. The aim of the study is to evaluate histologic risk factors for GC among patients with a DU.


Journal of Neurogastroenterology and Motility | 2013

Irritable Bowel Syndrome Is Associated With Gastroesophageal Reflux Symptom but Not Erosive Esophagitis

Su Youn Nam; Kum Hei Ryu; Bum Joon Park

Background/Aims Although several studies have suggested overlaps between gastroesophageal reflux symptom and irritable bowel syndrome (IBS), the studies for the association between erosive esophagitis and IBS are rare. The aim of this study was to evaluate the association among IBS, non-erosive reflux disease (NERD), and erosive esophagitis. Methods A total of 2,769 participants completed questionnaires and underwent esophagogastroduodenoscopy and colonoscopy. IBS was diagnosed by Rome III; NERD was defined as heartburn or acid regurgitation occurring at least once per week without erosive esophagitis. Erosive esophagitis was defined by Los Angeles classification. Psychological distress was evaluated with modified 4 dimensions from revised Hopkins symptom checklist 90. Results Psychological distress was associated with both IBS and NERD, but not with erosive esophagitis. IBS was associated with somatization (adjusted OR, 2.88; 95% CI, 1.55-5.36; P < 0.001), anxiety (adjusted OR, 2.82; 95% CI, 1.36-5.88; P = 0.005), and hostility (adjusted OR, 2.06; 95% CI, 1.10-3.87; P = 0.024) and NERD was associated with somatization (adjusted OR, 5.65; 95% CI, 2.92-10.98; P < 0.001) and anxiety (adjusted OR, 3.29; 95% CI, 1.47-7.34; P = 0.004). Erosive esophagitis was associated with somatization (adjusted OR, 2.69; 95% CI, 1.26-7.91; P < 0.001). Hiatal hernia and male sex were related with erosive esophagitis but not with IBS or NERD. H. pylori had an inverse relationship with erosive esophagitis, but had no association with IBS. Whereas IBS was positively associated with NERD (adjusted OR, 2.72; 95% CI, 1.84-4.03; P < 0.001), it had no association with erosive esophagitis. Conclusions IBS shared many risk factors with NERD but not with erosive esophagitis. It partially explains why IBS was associated with NERD, but not with erosive esophagitis.


European Journal of Gastroenterology & Hepatology | 2016

Effect of Helicobacter pylori infection and its eradication on the fate of gastric polyps.

Su Youn Nam; Bum Joon Park; Kum Hei Ryu; Ji Hyung Nam

Objectives Western guidelines recommend Helicobacter pylori eradication in H. pylori-associated gastric polyps, but Korean medical insurance does not approve its eradication. The aim of this study is to evaluate the effect of H. pylori eradication on gastric polyps. Methods Participants in a large screening cohort underwent baseline and follow-up esophagogastroduodenoscopy and H. pylori testing. The association between gastric polyps and H. pylori was estimated using odds ratios (ORs) adjusted for confounding factors and 95% confidence intervals (CIs). The effect of H. pylori eradication on the fate of polyps was also evaluated. Results The screening cohort included 7603 participants (605 gastric polyps: 529 hyperplastic polyps, 63 fundic gland polyps, and 13 adenomas). H. pylori infection showed a positive association with hyperplastic polyps (OR 2.01; 95% CI 1.66–2.41), but was inversely related to fundic gland polyps (OR 0.05; 95% CI 0.02–0.17). Removed polyps by biopsy or endoscopic resection or tiny polyps less than 3 mm at baseline and positive conversion of H. pylori at follow-up were excluded. A total of 7060 persons were finally included to evaluate the effect of H. pylori eradication on the gastric polyp. Successful H. pylori eradication (OR 0.52; 95% CI 0.35–0.77) and persistent H. pylori-negative status (OR 0.59; 95% CI 0.46–0.76) reduced the risk of hyperplastic polyps compared with the persistent H. pylori-positive group. Successful H. pylori eradication markedly induced the disappearance of hyperplastic polyps compared with the persistent H. pylori-positive group (85.0 vs. 29.0%, P=0.001). Conclusion H. pylori infection increased the risk of hyperplastic polyps in both cross-sectional and longitudinal settings, and its eradication induced regression of hyperplastic polyps.

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Su Youn Nam

Kyungpook National University

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Kwon Yoo

Ewha Womans University

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Hyun Joo Song

Jeju National University

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Ki-Nam Shim

Ewha Womans University

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Dae Kyung Sohn

Seoul National University

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