AIM: To explore the correlation between Helicobacter pylori(H. pylori)-associated gastric diseases and colorectal neoplasia.METHODS: Patients included in this study underwent a colonoscopy and esophago-gastro-duodenoscopy(EGD) along with histopathological measurement between March 2012 and March 2015 at Qi-Lu Hospital of Shandong University, who also had results of H. pylori detection. A total of 233 cases were selected. Demographic data, H. pylori infection status(including results of rapid urease tests and gastric mucosa pathological examinations) and histopathological examination results of gastric and colorectal mucosa were gathered and analyzed. The statistical analysis focused on the prevalence of colorectal neoplasms among patients with various histopathological categories of the stomach. ORs and their 95%CI were calculated to describe the strengths of the associations.RESULTS: The incidence rates of colorectal adenoma without high-grade intraepithelial neoplasia(HGIEN)(OR = 2.400, 95%CI: 0.969-5.941), adenoma with HGIEN(5.333, 1.025-27.758) and adenocarcinoma(1.455, 0.382-5.543) were all higher for patients with H. pylori-associated gastritis than for those in the control group. The incidence rate of colorectal adenoma with HGIEN(3.218, 0.767-13.509) was higher in patients with intestinal metaplasia than in the control group, while the incidence rates of adenoma without HGIEN(0.874, 0.414-1.845) and adenocarcinoma(0.376, 0.096-1.470) were lower in the intestinal metaplasia group than in the control group. The incidence rate of colorectal adenoma without HGIEN(3.111, 1.248-7.753) was significantly higher in the gastric intraepithelial neoplasia group than in the control group, while the rates of adenoma with HGIEN(1.481, 0.138-15.941) and adenocarcinoma(2.020, 0.561-7.272) were higher in the gastric intraepithelial neoplasia group. Incidence rates of colorectal adenoma without HGIEN(1.067, 0.264-4.314), adenoma with HGIEN(2.667, 0.231-30.800) and adenocarcinoma(2.182, 0.450-10.585) were all higher in the gastric adenocarcinoma group than in the control group.CONCLUSION: H. pylori infection as well as H. pylori-associated gastric diseases are risk factors for colorectal neoplasia. AIM: To explore the correlation between Helicobacter pylori (H. pylori) -associated gastric diseases and colorectal neoplasia. METHODS: Patients included in this study underwent a colonoscopy and esophago-gastro-duodenoscopy (EGD) along with histopathological measurement between March 2012 and March 2015 at Qi-Lu Hospital of Shandong University, who also had results of H. pylori detection. A total of 233 cases were selected. Demographic data, H. pylori infection status (including results of rapid urease tests and gastric mucosa pathological examinations) and histopathological examination results of gastric and colorectal mucosa were gathered and analyzed. The statistical analysis focused on the prevalence of colorectal neoplasms among patients with various histopathological categories of the stomach. ORs and their 95% CI were calculated to describe the strengths of the associations .RESULTS : The incidence rates of colorectal adenoma without high-grade intraepithelial neoplasia (HGIEN) (OR = 2.4 00, 95% CI: 0.969-5.941), adenoma with HGIEN (5.333, 1.025-27.758) and adenocarcinoma (1.455, 0.382-5.543) were all higher for patients with H. pylori-associated gastritis than for those in the control group. The incidence rate of colorectal adenoma with HGIEN (3.218, 0.767-13.509) was higher in patients with intestinal metaplasia than in the control group, while the incidence rates of adenoma without HGIEN (0.874, 0.414-1.845) and adenocarcinoma (0.376, 0.096- 1.470) were lower in the intestinal metaplasia group than in the control group. The incidence rate of colorectal adenoma without HGIEN (3.111, 1.248-7.753) was significantly higher in the gastric intraepithelial neoplasia group than in the control group, while the rates of adenoma with HGIEN (1.481, 0.138-15.941) and adenocarcinoma (2.020, 0.561-7.272) were higher in the gastric intraepithelial neoplasia group. Incidence rates of colorectal adenoma without HGIEN (1.067, 0.264-4.314), adenoma with HGIEN (2.667, 30.800) and adenocarcinoma (2.182, 0.450-10.585) were all higher in the gastric adenocarcinoma group than in the control group. CONCLUSION: H. pylori infection as well as H. pylori-associated gastric diseases are risk factors for colorectal neoplasia.