H. pylori and functional dyspepsia: increased serum antibodies as an independent risk factor?

The relationship between H. pylori and functional dyspepsia is controversial. Hypothesizing that subjects with a more intense immune response to H. pylori (and hence higher antibody titers) would be at greater risk of dyspepsia, we aimed to identify risk factors for the development of dyspeptic symptoms. In all, 491 healthy blood donors with no history of peptic ulceration and 74 consecutive patients with a confirmed diagnosis of functional dyspepsia were studied. Symptoms and potential risk factors [nonsteroidal antiinflammatory drugs (NSAIDs), alcohol, and smoking] were measured by a validated questionnaire. H. pylori status was determined by IgG antibodies using a validated ELISA test with a cutoff titer for a positive serology of 10 units/ml. Logistic regression analysis assessed the association between risk factors and dyspepsia. Among blood donors, 21% (95% CI 17.6-24.8) reported dyspepsia (pain localized to the upper abdomen); 7.7% (95% CI 5.5-10.4) had frequent dyspepsia (>6 times in the prior year). The age-adjusted prevalence of H. pylori was not significantly different in blood donors with (39.5%, 95% CI 24.0-56.6) and without frequent dyspepsia (34.2%, 95% CI 29.8-38.36), but was significantly greater in patients with functional dyspepsia (68.8%, 95% CI 57.3-77.9). In the combined study population of blood donors and patients with functional dyspepsia, logistic regression adjusting for age identified the following independent risk factors for frequent dyspepsia: high serum antibody levels against H. pylori (OR for IgG titer >50 units/ml vs H. pylori titers 11-50 units/ml 4.6, 95% CI 2.7-7.8) and consumption of standard NSAIDs (OR 2.4,95% CI 1.3-4.5). In contrast, alcohol (OR 0.6, 95% CI 0.3-1.0), smoking (OR 1.5, 95% CI 1.0-2.3) or positive H. pylori serology with titers < or = 50 units/ml (OR 1.6, 95% CI 0.8-2.9) were not associated with frequent dyspepsia. In conclusion, in a subgroup of H. pylori-infected subjects who have high antibody titers, H. pylori appears to be associated with functional dyspepsia.