Background: The prevalence of Helicobacter pylori infection in Crohn's disease (CD) patients was investigated to determine whether the presence and severity of gastroduodenal lesions were related to H. pylori infection.

Methods: Infection rates were compared between CD group (n = 90) and the control group (n = 525). Correlations between endoscopically detected lesions and H. pylori positive rates were investigated. The relationship between drug therapy and the prevalence of H. pylori infection was also analyzed.

Results: H. pylori-positive rate of the 90 CD patients attending our clinic was 16.7%, significantly lower than the rate in healthy controls (40.2%) (P = 0.0001). The involvement of H. pylori infection in the gastroduodenal lesions of CD patients was also examined. The prevalence of gastroduodenal lesions in all CD patients was high, 92.2%. The lesions observed included ulcers, erosion, and "bamboo joint-like lesions" of the stomach, and ulcers, erosion, stenosis, and elevated lesions of the duodenum. None of these lesions were found to be related to H. pylori infection. However, H. pylori infection was found to exacerbate gastric ulcers (P = 0.036). The analysis of a possible relationship between a history of drug therapy and the low prevalence of H. pylori infection in CD patients showed that the prevalence of H. pylori infection was significantly lower in patients who had received antibiotics for 2 weeks or more (P = 0.002).

Conclusions: The results suggest that H. pylori infection is essentially unrelated to the gastroduodenal lesions observed in CD. It seems likely, however, that H. pylori infection may exacerbate gastric ulcers and that H. pylori can be eradicated by prolonged use of antibiotics.