Observation of gastric mucosa in Bangladesh, the country with the lowest incidence of gastric cancer, and Japan, the country with the highest incidence

Abstract

Background: The prevalence of Helicobacter pylori (H. pylori) infection is high, but the incidence of gastric cancer is low in natives of Bangladesh. The gastric mucosa was observed in Bangladeshi patients to investigate the differences between Bangladeshis and Japanese.

Materials and methods: The study involved 418 Bangladeshi and 2356 Japanese patients with abdominal complaints who underwent endoscopy examinations and had no history of H. pylori eradication. The prevalence of H. pylori infection and the gastric mucosa in H. pylori-positive patients were compared between age-, gender-, and endoscopic diagnosis-matched Bangladeshi and Japanese subjects.

Results: The prevalence of H. pylori infection was higher in Bangladeshi than in Japanese subjects (60.2 and 45.1%, respectively). All the scores for chronic inflammation, neutrophil activity, glandular atrophy, and intestinal metaplasia were significantly lower in H. pylori-positive Bangladeshis than in H. pylori-positive Japanese. The ratio of the corpus gastritis score (C) to the antrum gastritis score (A) (C/A ratio) was <1 (antrum-predominant gastritis) in all age groups of Bangladeshi subjects, whereas the C/A ratio changed from <1 to more than 1 (corpus-predominant gastritis) with aging in Japanese subjects.

Conclusions: The scores for glandular atrophy and intestinal metaplasia in H. pylori-positive Bangladeshis were significantly lower than those in Japanese. All age groups of Bangladeshis had antrum-predominant gastritis, whereas corpus-predominant gastritis was more common than antrum-predominant gastritis in older Japanese age groups. These results may explain the low incidence of gastric cancer in Bangladeshis and the high incidence in Japanese.

Figure 1

Triple-site biopsy sections are used for the histological diagnosis of chronic inflammation, neutrophil activity, glandular atrophy, intestinal metaplasia, and Helicobacter pylori in the gastric mucosa. It was determined between us and a pathologist that section #1 should be taken from the greater curvature of the lower antrum (Antrum), #2 from the greater curvature of the upper corpus (Corpus), and #3 from the lesser curvature of the lower corpus (Angulus). Section #4 and others are taken from the ulcers or cancer lesions.

Figure 2

The prevalence of Helicobacter pylori infection was 60.0% in all Bangladeshi subjects (418 patients). When compared by age group, the prevalence was highest at ages 20–29, followed by ages 50–59. The prevalence tended to decrease at ages 60 or older (41.2% at ages 60–69, 33.3% at ages 70 or older).

Figure 3

Chronic inflammation, neutrophil activity, glandular atrophy, and intestinal metaplasia scores were compared between Helicobacter pylori-positive Bangladeshis and Japanese at each biopsy site, and mean scores in all biopsy sites were significantly higher in Japanese than in Bangladeshis.

Figure 4

Chronic inflammation and neutrophil activity scores were compared between Helicobacter pylori-positive and -negative Bangladeshi subjects in each biopsy site, and mean scores in all biopsy sites were significantly higher in H. pylori-positive Bangladeshis. Glandular atrophy and intestinal metaplasia scores were also compared between H. pylori-positive and -negative Bangladeshi subjects in each biopsy site, and no differences were found in the mean scores for any biopsy site.

Figure 5

The ratio of the corpus gastritis score to the antrum gastritis score (C/A ratio) was compared between Helicobacter pylori-positive Bangladeshi and Japanese patients in each age group. All age groups of Bangladeshis had a C/A ratio of <1 (antrum-predominant gastritis). On the other hand, Japanese aged 59 years or younger had a C/A ratio indicating antrum-predominant gastritis, whereas those aged 60 years or older had a C/A ratio of more than 1, indicating that these Japanese had corpus-predominant gastritis in place of antrum-predominant gastritis.