Association among helicobacter pylori infection, gastrin level and colorectal cancer in patients aged 50 years and over

OBJECTIVES: To study the correlations among helicobacter pylori infection, gastrin and colorectal cancer in patients aged over 50 years old. METHODS: In this study, the patients diagnosed with colorectal cancer treated in the department of digestion of our hospital together with the healthy subjects undergoing colonoscopy for health examination without pathologic findings from August 2016 to July 2019 were enrolled in colorectal cancer or control group. The blood sample was taken in fasting state, and anti-H. pylori IgG and anti-CagA antibodies as well as the level of serum gastrin were measured for all the participants. In addition, the information of each participant including age, gender, obesity, smoking history, alcohol consumption, diabetes mellitus was recorded and analyzed. RESULTS: Four hundred and twenty-eight patients were enrolled in the colorectal group and 207 healthy subjects were enrolled in the control group. There were not significant differences in the positive rate of Ig G and Cag A and family history between the two groups (p>0.05), but there were significant differences in gastrin level, obesity, smoking history, alcohol consumption and diabetes mellitus between the two groups (p<0.05). In addition, the multivariable analysis showed that obesity, smoking history, alcoholism and diabetes mellitus have the strongest influence on the formation of colorectal cancer, while the level of gastrin didn’t show the influence. CONCLUSIONS: No significant correlations among H. pylori infection, the level of gastrin, and the occurrence of CRC in patients with a minimum age of 50 years, suggesting elder colorectal cancer patients may have a different carcinogenic mechanism from those younger patients.