Helicobacter pylori and the risk of colonic adenomas. Colorectal Adenoma Study Group.

Aims: Previous studies have found a positive association between Helicobacter pylori infection and colorectal adenomas. The aim of the present study was to examine this association while taking possible confounding factors into account.

Methods: 98 serum samples were available from 182 patients with colorectal adenomas who entered a case-control study of colorectal adenomas and diet. The H. pylori status in patients was compared with a hospital control group and a population control group.

Results: H. pylori IgG antibodies were more common in colorectal polyp patients compared with either control group, the prevalence being 79% in cases compared with 62% in both control groups. The corresponding RR was 1.4 (0.76-2.6) compared with hospital controls and 2.1 (1.1-3.9) compared with population controls. After adjusting for possible confounding variables the association between H. pylori status and adenoma risk was even more marked. There was an RR of 1.6 (0.80-3.4) compared with hospital controls and an RR of 2.6 (1.3-5.4) compared with population controls, the latter association being statistically significant.

Conclusion: These findings suggest a statistically significant association between H. pylori infection and colorectal polyps. A possible mechanism might be increased gastrin levels in H. pylori-infected subjects which exhibit a trophic effect on colonic mucosa.