[Epidemiology of Helicobacter pylori infection in Shandong and Beijing areas.].

Objectives: To study the current prevalence and recent epidemiological changes of Helicobacter pylori (H. pylori) infection among children and adults residing in regions with high (Muping, Shandong) and low (Yanqing, Beijing) incidence of gastric cancer in China.

Methods: A total of 2065 asymptomatic children aged 8 - 15 years and adults aged 40 - 79 years in the above two regions were examined from May to July 2006. The data obtained in early 1990s in the same two areas and those of 11 656 patients undergoing endoscopy in our hospital in 1991 and 2006 were also collected and studied.

Results: The prevalence of H. pylori infection in Muping was significantly higher than that in Yanqing among both children (37.69% vs 25.58%, P < 0.001) and adults (50.95% vs 41.35%, P < 0.01). From 1991 to 2006 H. pylori prevalence among children aged 8 - 10 years decreased in Muping (60.00% vs 32.07%, P < 0.001), but not in Yanqing (24.06% vs 19.10%, P > 0.05). A significant decrease in H. pylori prevalence among adults in both regions was observed when the results of 2006 were compared with the data obtained in 1990 in Muping (50.95% vs 73.78%, P < 0.001) and in 1992 in Yanqing (41.35% vs 55.35%, P < 0.01). The detected rate of H. pylori infection in patients undergoing endoscopy in our hospital decreased from 51.88% in 1991 to 33.59% in 2006 (P < 0.001).

Conclusions: The prevalence of H. pylori infection is significantly higher in areas with a high incidence of gastric cancer in China as compared with that in areas with a low incidence of gastric cancer among both children and adults. H. pylori infection may be a risk factor in gastric carcinogenesis. In the past decade or more, H. pylori infection rates have decreased in Chinese population.