Helicobacter pylori independent chronological change in gastric acid secretion in the Japanese

Abstract

Background: Gastric acid secretion in Japanese subjects decreases with aging. One of the possible causative mechanisms of this attenuated acid secretion is speculated to be a Helicobacter pylori induced chronic gastritis. The infection rate of this microorganism has decreased recently in Japan.

Aims: To investigate whether gastric acid secretion has altered over the past 20 years, and if so, what the influence of H pylori infection might be in the Japanese population.

Subjects and methods: Gastric acid secretion, serum gastrin and pepsinogen I and II concentrations, and H pylori infection were determined in 110 Japanese subjects in both the 1970s and 1990s.

Results: Basal acid output as well as maximal acid output have greatly increased over the past 20 years, not only in individuals with H pylori infection but also in those without infection. Furthermore, subjects with H pylori infection tended to show decreased gastric acid secretion in comparison with those without infection, particularly in geriatric subjects. There was a positive correlation between gastric acid secretion and serum pepsinogen I concentrations.

Conclusions: In Japan, both basal and stimulated gastric acid secretion have increased over the past 20 years; some unknown factors other than the decrease in H pylori infection may play an important role in this phenomenon.

Figure 1

: BAO in the eight groups. Each dot represents a single case. Horizontal lines indicate medians of individual groups. **Significant difference (p<0.01) between H pylori positive and negative groups (group 7 v group 3); *significant difference (p<0.05) between H pylori positive and negative groups (group 8 v group 4).

Figure 2

: MAO in the eight groups. Each dot represents a single case. Horizontal lines indicate medians of individual groups. **Significant difference (p<0.01) between H pylori positive and negative groups (group 8 v group 4); *significant difference (p<0.05) between H pylori positive and negative groups (group 6 v group 2, and group 7 v group 3).

Figure 3

: Serum gastrin concentrations in the eight groups. Each dot represents a single case. Horizontal lines indicate medians of individual groups.

Figure 4

: Correlation between serum gastrin concentrations and BAO in the 1970s and 1990s. Each dot represents a single case. Solid lines represent the regression plots; dotted lines represent 95% confidence bands.

Figure 5

: Serum pepsinogen I concentrations in the eight groups. Each dot represents a single case. Horizontal lines indicate medians of individual groups.

Figure 6

: Serum pepsinogen II concentrations in the eight groups. Each dot represents a single case. Horizontal lines indicate medians of individual groups. **Significant difference (p<0.01) between H pylori positive and negative groups (group 5 v group 1, group 6 v group 2, group 7 v group 3, and group 8 v group 4).

Figure 7

: Correlation between serum pepsinogen I concentrations and gastric acid secretion. Each dot indicates a single case. Solid lines represent the regression plots; dotted lines represent 95% confidence bands.