Seasonal variation in the frequency of Helicobacter pylori infection: A possible cause of the seasonal occurrence of peptic ulcer disease

Objectives: The seasonal variation of duodenal ulcer disease and its complications have been repeatedly demonstrated in Israel by several independent studies. The aim of this study was to determine possible seasonal variations in the occurrence of H. pylori infection among dyspeptic patients in Israel. Methods: All ¹⁴C-urea breath tests performed in dyspeptic patients at the gastroenterology department in the Tel Aviv Medical Center from January 1991 to December 1992 were reviewed. The monthly variation in the proportion of patients with H. pylori infection was determined, and compared with that of an unrelated ¹⁴C-cholyl-glycine breath test. Results: Altogether, 702 patients were examined, and 371 (52.8%) of them were found to be infected with H. pylori. During summer months (July-September), a significant decrease in the percentage of patients infected with H. pylori was found, compared with winter months (December-January, 42.3% vs. 60.9%, p < 0.007). No seasonal variation was found in the results of ¹⁴C-cholyl- glycine test. The fluctuations in H. pylori infection were highly correlated with the seasonal occurrence of peptic ulcer disease in Israel. Conclusions: The frequency of H. pylori infection in dyspeptic patients in Israel is significantly increased during the winter months and decreased in the summer. This seasonal variation is identical to that found in duodenal ulcer disease. Thus, the seasonal variation of peptic ulcer disease could be explained by H. pylori infection, as seen in other communicable infectious diseases.