OBJECTIVES: The aims of this prospective study were to document the incidence of colon immediate postpolypectomy bleeding (IPPB) according to grade, and to identify potential risk factors of IPPB in patients who have received complete colonoscopy and polypectomy because of a colorectal polyp. METHODS:This was a prospective, cross-sectional study of 5,152 patients treated at 11 tertiary medical centers between July 2003 and July 2004. Patient-related, polyp-related, and procedure-related variables were evaluated as potential risk factors for IPPB. IPPB was defined as a bleeding occurring during the procedure and was graded as G1-G4. Risk factors associated with IPPB were analyzed by univariate and multivariate logistic regression analysis. RESULTS:A total of 9,336 colonic polyps were removed in 5,152 patients, and 262 (2.8%) colorectal polyps in 215 patients presented with IPPB. Polyp-based multivariate analysis revealed that old age (≥65 yr), comorbid cardiovascular or chronic renal disease, anticoagulant use, polyp size greater than 1 cm, gross morphology of polyps such as pedunculated polyp or laterally spreading tumor, poorer bowel preparation, cutting mode of the electrosurgical current, and the inadvertent cutting of a polyp before current application were significant risk factors for IPPB.CONCLUSION: Nine factors have been found to be associated with IPPB and polypectomy should be undertaken with caution under these conditions.

Our study provides new biological insight to CD and supports the complementary value of genetic studies in different populations.

The prevalence of endoscopic reflux esophagitis among Koreans is 3.4%, and most of the patients had a mild grade esophagitis. Smoking, alcohol consumption, the presence of a hiatal hernia and a higher BMI are associated with the development of reflux esophagitis.

Background Crohn's disease (CD) is an intractable inflammatory bowel disease of unknown cause. Recent genome-wide association studies of CD in Korean and Japanese populations suggested marginal sharing of susceptibility loci between Caucasian and Asian populations. As the 7 identified loci altogether explain 5.31% of the risk for CD, the objective of this study was to identify additional CD susceptibility loci in the Korean population. Methods Using the ImmunoChip custom single-nucleotide polymorphism array designed for dense genotyping of 186 loci identified through GWAS, we analyzed 722 individuals with CD and 461 controls for 96,048 SNP markers in the discovery stage, followed by validation in an additional 948 affected individuals and 977 controls. Results We confirmed 6 previously reported loci in Caucasian: GPR35 at 2q37 (rs3749172; P = 5.30 × 10−11, odds ratio [OR] = 1.45), ZNF365 at 10q21 (rs224143; P = 2.20 × 10−9, OR = 1.38), ZMIZ1 at 10q22 (rs1250569; P = 3.05 × 10−7, OR = 1.30), NKX2-3 at 10q24 (rs4409764; P = 7.93 × 10−8, OR = 1.32), PTPN2 at 18p11 (rs514000; P = 9.00 × 10−8, OR = 1.33), and USP25 at 21q11 (rs2823256; P = 2.49 × 10−7, OR = 1.35), bringing the number of known CD loci (including 3 in the HLA) in Koreans to 15. The 6 additional loci increased the total genetic variance for CD risk from 5.31% to 7.27% in Koreans. Conclusions Although the different genetic backgrounds of CD between Asian and Western countries has been well established for the major susceptibility genes, our findings of overlapping associations offer new insights into the genetic architecture of CD.

The overall prevalence of colorectal neoplasm in asymptomatic average-risk Koreans is comparable with that in Western countries. Being male and older are associated with a higher risk of colorectal neoplasm. Over half of proximal neoplasms are not associated with any distal sentinel lesions.