Seon Hee Lim

Prevalence and risk factors of Helicobacter pylori infection in Korea: Nationwide multicenter study over 13 years

BackgroundThe aim of this study was to evaluate the time trend of seropositivity of Helicobacter pylori (H. pylori) over the period of 13 years in an asymptomatic Korean population, and investigate associated risk factors.MethodsThis cross-sectional nationwide multicentre study surveyed anti-H. pylori IgG antibodies in 19,272 health check-up subjects (aged [greater than and equal to]16 years) in 2011. Risk factors for H. pylori infection were investigated using logistic regression. Seropositivity in asymptomatic subjects without H. pylori eradication was compared between the years 1998 and 2005. Birth cohort effects were also evaluated.ResultsAfter exclusion of subjects with a history of H. pylori eradication therapy (n = 3,712, 19.3%) and gastric symptoms (n = 4,764, 24.7%), the seroprevalence of H. pylori infection was 54.4% in 10,796 subjects. This was significantly lower than the seroprevalence of 59.6% in 2005 and that of 66.9% in 1998, and this decrease of seropositivity of H. pylori became widespread across all ages and in most areas of the country. This decreasing trend could be explained by cohort analysis. All younger birth cohorts had a lower seroprevalence of H. pylori than older birth cohorts at the same age. Decreased seroprevalence within the same birth cohorts also accounted for this phenomenon. Clinical risk factors of H. pylori infection were higher cholesterol level ([greater than and equal to] 240 mg/dl) (OR = 1.33; 95% CI = 1.14-1.54), male gender, older age, low income, and residence in a rural area.ConclusionsA decreasing trend of H. pylori seroprevalence due to a birth cohort effect requires further studies on its related human host factors as well as socio-economic and hygienic factors. In addition, the relationship between H. pylori infection and high cholesterol level needs more investigation regarding underlying pathogenesis.

Helicobacter pylori infection and development of gastric cancer in Korea: long-term follow-up.

Background and Aim Infection of Helicobacter pylori is viewed as a major driver of progression to the precancerous state or to gastric cancer. This study was performed to investigate the effect of H. pylori infection on gastric cancer development and to determine to what extent H. pylori eradication is likely to reduce the prevalence of gastric cancer. Methods Gastric cancer development was investigated in 1790 Korean subjects who underwent gastroscopy and H. pylori testing between 1992 and 1998. The effects of H. pylori-positive and eradicated states on gastric cancer development were analyzed. Results Gastric cancer developed in 5 of the study cohort during a mean follow-up period of 9.4 years. All of these patients were positive for H. pylori infection, and 4 of the 5 had antral intestinal metaplasia (IM) at the time of study enrollment. One of these 5 patients was in an eradicated state when the gastric cancer was diagnosed, and had histologic IM before eradication therapy was performed. Gastric cancer was found to develop 10.9 times more frequently in the presence of IM than in its absence. Conclusions The present study shows a close relationship between H. pylori infection and IM, and between IM and the development of gastric cancer. In addition, our finding suggests that chronic H. pylori infection looks like an important risk factor for the development of gastric cancer in Korea, where the prevalence of H. pylori remains high. This study indicates that to prevent gastric cancer H. pylori eradication is best performed before the development of IM.

Sagittal abdominal diameter is a strong anthropometric measure of visceral adipose tissue in the Asian general population.

OBJECTIVE Finding the anthropometric measure of visceral obesity is essential to clinical practice, because it predicts cardiovascular and metabolic risks. Sagittal abdominal diameter (SAD) has been proposed as an estimate of visceral adipose tissue (VAT). The aim of the present study was to evaluate the usefulness of SAD in predicting visceral obesity by comparing SAD to other anthropometric measures. RESEARCH DESIGN AND METHODS Estimation of subcutaneous and visceral adipose tissue and measurement of SAD and transverse abdominal diameter using computed tomography at the umbilical level were obtained in 5,257 men and women who were enrolled in a health checkup program in Korea. To compare SAD to other anthropometric measures, linear regression analyses were used to determine correlations between anthropometrics and visceral obesity. RESULTS SAD showed a stronger correlation to VAT than waist circumference, BMI, and transverse abdominal diameter in the both sexes (men: r = 0.804, women: r = 0.724). Waist circumference showed generally stronger associations to subcutaneous adipose tissue (SAT) than to VAT (men: r = 0.789 vs. 0.705, women: r = 0.820 vs. 0.636). Even after subdividing according to age or BMI in both sexes and analyzing multiple regressions, SAD showed the strongest correlation to VAT. CONCLUSIONS SAD showed the strongest correlation to VAT irrespective of age, sex, and the degree of obesity compared with other anthropometric measures, whereas waist circumference may have a stronger correlation to SAT than to VAT. The clinical use of SAD has advantages over other anthropometric measures in predicting VAT.

Helicobacter pylori reinfection rate and duodenal ulcer recurrence in Korea.

In the short term, the eradication of Helicobacter pylori in patients with duodenal ulcer (DU) is deemed to be clearly effective; the long-term effectiveness apparently depends on the H. pylori reinfection rate. We conducted the present study to investigate the rates of H. pylori reinfection and DU recurrence in 45 patients previously cured of DU in whom H. pylori had been eradicated. These patients underwent gastroscopy and tests for H. pylori at least 1 year after eradication. In a control group comprising 31 patients with DU who were not treated with H. pylori eradication regimen, the DU recurrence rate was checked annually for 4 years. Twenty of 45 patients (44.4%) in whom the mean follow-up period was 3.5 years were again found to be H. pylori positive, and the reinfection rate was 12.8% per year. DU recurred in 8 of these 20 (40%) but not in any nonreinfected patients. In the control group, the DU recurrence rate was 61% within 1 year, 81% within 2 years, 84% within 3 years, and 90% within 4 years. The respective recurrence rates in the 45 patients in whom the bacteria had been eradicated were 0%, 4%, 13%, and 18%. The H. pylori reinfection rate was as high as 12.8% per year in Korea, but in that the DU recurrence rate is significantly lower (p < 0.01; odds ratio, 129.5) in the H. pylori-eradicated group than in the control group, the eradication of H. pylori in DU patients is effective over the long term (at least 4 years).

Prospective evaluation of a new stool antigen test for the detection of Helicobacter pylori, in comparison with histology, rapid urease test, 13C-urea breath test, and serology

Background and Aims:  This study aimed to evaluate the efficacy of a new polyclonal enzyme immunoassay for the detection of Helicobacter pylori (H. pylori) antigen in stool by determination of the optimal cut‐off value in the screening population.

Helicobacter pylori in Dental Plaque and Saliva

Background About half of the world population is infected with H. pylori, but the transmission and the source of this infection are still unclear. Recently, dental plaque (DP) and saliva have been implicated as possible sources of H. pylori infection. This study was done to investigate the detection rates of H. pylori in the DP and saliva by use of PCR depending on H. pylori infection state of gastric mucosa. Methods In 46 subjects, gastric H. pylori colonization was evaluated with CLO test, microscopy of Gram stained mucosal smear, culture and histology after modified Giemsa staining in the antrum and body, respectively. A patient was regarded as H. pylori positive if one or more of the four aforementioned test methods demonstrated H. pylori colonization of the gastric mucosa. For detection of H. pylori in the DP and saliva, PCR assay was done with ET4-U and ET4-L primers. To estimate the sensitivity and specificity of this PCR, H. pylori positivity was evaluated in the antrum and body, separately. Results The sensitivity of mucosal PCR was 50.0% (27/54) and the specificity 86.8% (33/38). When a subject was regarded as H. pyloi positive, if either antrum or body mucosal H. pylori was is positive, the positive rate of mucosal PCR was 62.1% (18 subjects) in the 29 H. pylori-positive and 17.6% (3 subjects) in the 17 H. pylori-negative subjects. DP PCR was positive in 2 of 29 H. pylori-positive subjects (6.9%) and none in the 17 H. pylori-negative (0%). Saliva PCR was positive in 4 of 14 H. pylori-positive subjects (28.6%) and none of 6 H. pylori-negative (0%). Conclusion The detection rates of H. pylori in DP and saliva by PCR were rather low, 6.9% and 28.6%, respectively, and these rates might have been underestimated by low sensitivity of the PCR method used in this study. However, the results that H. pylori was found in the DP and saliva suggest that the oral cavity can perform a role as a reservoir of H. pylori in Korea.

Long-term effects of Helicobacter pylori eradication on intestinal metaplasia in patients with duodenal and benign gastric ulcers

This study was conducted to investigate whether or not the eradication of H. pylori could lead to the regression of intestinal metaplasia (IM) in patients with either duodenal ulcer (DU) or benign gastric ulcer (BGU). The initial antral IM grade was 0.21 in the 72 patients of the H. pylori-eradicated DU group, this decreased to 0.17, 0.14, 0.13, and 0.09 after periods of four weeks, one year, two years, and four years, respectively, but without statistical significance. In the corpus of the DU group, where IM grade was low (0.02), there was no detectable change in IM. The initial antral IM grade of 0.69 in the 41 patients of the H. pylori-eradicated BGU group decreased substantially to 0.61, 0.44, and 0.39 after periods of four weeks and one and two years, respectively, but again without statistical significance. The initial corporal IM grade of the BGU group of 0.27 decreased to 0.20, 0.15, and 0.06 after periods of four weeks and one and two years, again without statistical significance. In contrast, the IM grades of the noneradicated DU group (N = 20) and the BGU group (N = 16) showed nearly no change in the antrum and corpus. Gastritis grades of antrum and corpus in the H. pylori-eradicated DU or BGU group significantly decreased with respect to time (P = 0.0001), but there were no significant changes in the corresponding noneradicated groups. Although there was no statistical significance, IM decreased in the antrum and corpus of the stomach with BGU and in antrum of those with DU over a two to four-year period after H. pylori eradication, suggesting the possible reversibility of IM.

Nonalcoholic fatty liver disease as a risk factor of cardiovascular disease; Relation of non-alcoholic fatty liver disease to carotid atherosclerosis

BACKGROUND/AIMS Non-alcoholic fatty liver disease (NAFLD) is closely associated with abdominal obesity, dyslipidemia, hypertension, and Type 2 diabetes, which are all features of the metabolic syndrome. The aim of the present study was to elucidate whether NAFLD is associated with carotid atherosclerosis. METHODS The study population comprised 659 subjects without hepatitis B and C infections and who did not consume alcohol. Fatty infiltrations of liver were detected by abdominal ultrasonography, and intima-media thickness (IMT) and plaque prevalence were estimated by carotid ultrasonography. RESULTS The mean values of systolic and diastolic pressures, body mass index (BMI), aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transpeptidase, uric acid, total cholesterol, triglycerides, high density lipoprotein (HDL) cholesterol, fasting glucose, fasting insulin, homeostasis model of assessment (HOMA) index, hemoglobin A1c, and plasminogen activator inhibitor-1 differed significantly between patients with NAFLD (n=314) and normal controls (n=345). The carotid IMT was 0.817+/-0.212 (mean+/-SD) mm in patients with NAFLD and 0.757+/-0.198 mm in normal controls (p<0.001). The prevalence of carotid plaques was higher in patients with NAFLD (26.4%) than in normal controls (15.9%) (p<0.001). This association persisted significantly after adjusting for age, sex, BMI, HOMA index and individual factors of metabolic syndrome by multiple logistic regression analysis. CONCLUSIONS Patients with NAFLD are at a high risk of carotid atherosclerosis regardless of metabolic syndrome and classical cardiovascular risk factors. Therefore, the detection of NAFLD should alert to the existence of an increased cardiovascular risk. Moreover, NAFLD might be an independent risk factor for cardiovascular disease.

Helicobacter pylori Serology Inversely Correlated With the Risk and Severity of Reflux Esophagitis in Helicobacter pylori Endemic Area: A Matched Case-Control Study of 5,616 Health Check-Up Koreans

Background/Aims The role of Helicobacter pylori in gastroesophageal reflux disease remains still controversial and the effect of the organism on severity of reflux esophagitis have been rarely issued. The aim of this study was to investigate the relationship between H. pylori infection and reflux esophagitis, and especially the severity of reflux esophagitis. Methods We performed a cross-sectional case-control study of 5,616 subjects undergoing both upper endoscopy and H. pylori serology during health Check-up (2,808 cases vs age- and sex-matched controls). Smoking, alcohol, body mass index and waist circum - ference were added to a multiple regression model. Results Prevalence of H. pylori infection was lower in cases with reflux esophagitis than in controls (38.4% vs 58.2%, P < 0.001) and negative associations with H. pylori infection continued across the grade of esophagitis (46.7% in Los Angeles classification M [LA-M], 34.3% in LA-A or LA-B and 22.4% in LA-C or LA-D, P < 0.001). Positive serology for H. pylori independently reduced the risk of reflux esophagitis (adjusted OR, 0.44; 95% CI, 0.39-0.49). Notably, the negative associations continued across the grade of esophagitis with adjusted ORs of 0.63 in LA-M, 0.36 in LA-A or LA-B and 0.20 in LA-C or LA-D (P < 0.001). Conclusions In a age-sex matched Korean, H. pylori seropositivity was independently and inversely associated with the risk and severity of reflux esophagitis, suggesting the organism may have a protective role against gastroesophageal reflux disease.

The efficacy of intravenous contrast-enhanced 16-raw multidetector CT colonography for detecting patients with colorectal polyps in an asymptomatic population in Korea.

Purpose The purpose of this study is to compare the sensitivity of computed tomography (CT) colonography (CTC) with that of colonoscopy for detecting patients with colorectal polyps in an asymptomatic screening population in Korea, thus to evaluate a possibility, whether CTC could be used as a screening tool for colorectal polyps. Methods A total of 241 asymptomatic adults underwent intravenous contrast-enhanced CTC and colonoscopy successively on the same day. Bowel preparation was performed by 4 L of polyethylene glycol (n=172) or 90 mL of sodium phosphate (n=69). The CTC findings were released to the colonoscopists after the first examination of each segment, a procedure known as segmental unblinded colonoscopy, and were used as the reference standard. The diagnostic performance of CTC for colorectal polyps was calculated. Results The per-patient sensitivities of CTC were 68.5% (37/54) and 86.7% (13/15) for polyp ≥6 and ≥10 mm, inferior to those of colonoscopy, 92.6% (50/54) and 100% (15/15), respectively. The per-polyp sensitivities of CTC were 60.4% (61/101) and 72.7% (16/22) for polyp ≥6 and ≥10 mm, respectively. The low sensitivity of CTC was related with flat morphology. CTC detected only 37.5% (9/24) of flat polyps ≥6 mm. Bowel preparation by sodium phosphate further decreased the positive predictive value and specificity than by polyethylene glycol. Conclusions Screening by CTC with asymptomatic population was not promising in Korea despite using advanced CT technology (16-row detector). Bowel preparation was one of the key determinants of the specificity of CTC.