Helicobacter pylori and gastric hyperacidity, and their association with recurrent aphthous stomatitis.

Helicobacter pylori is an established cause of gastric ulcers. Its role in causing recurrent aphthous stomatitis (RAS) remains controversial. Fifty-two RAS patients and 52 sex-matched controls were recruited in this case-control study. All subjects were screened for hematinic deficiencies and H. pylori. The latter was assessed quantitatively using the 14C-urea breath test. The χ2 test and Wilcoxon signed ranks test were used to compare H. pylori and hematinic indices between cases and controls, while conditional logistic regression was used to assess the associations between the occurrence of RAS and independent factors. H. pylori was positive in 56.7% of the overall sample, with no difference between RAS patients (50.8%) and controls (49.2%) (P =  0.843). The median H. pylori and haematological indices values did not show any association with ulcer diameter, number, or frequency. Interestingly, gastric hyperacidity was significantly associated with RAS, and this association was independent from tobacco smoking, alcohol drinking, and H. pylori (odds ratio 14.99, 95% confidence interval 2.47-90.95; P =  0.003). This study found no association between H. pylori and RAS. The association between RAS and gastric hyperacidity suggests that gastric refluxate, not H. pylori, has an effect on the oral mucosa that favours an ulcerative change.