Helicobacter pylori (Hp) is a major risk factor for gastric carcinogenesis.
In Japan, the incidence of Hp infection in young adults has declined marke
dly. The purpose of this study was to clarify this trend in the incidence o
f Hp-associated gastric carcinoma (GCa) in young (under 30 years of age) Ja
panese patients. We enrolled 53 such patients who underwent surgical resect
ion of GCa in one of 18 hospitals in the Hiroshima prefecture between 1976
and 1999. The patients were classified into groups based on three 8-year pe
riods (1976-83, 1984-91, and 1992-1999) in which their cases occurred. We c
ompared the numbers of patients and estimated the histology of carcinomas,
grades of gastritis and Hp infection histologically. Of the 53 patients, 49
(92%) showed Hp infection. The frequency of GCa in young adults has decrea
sed gradually (21, 18, and 14 patients in 1976-83, 1984-91 and 1992-99, res
pectively). The numbers of Hp-positive carcinomas decreased radically (21,
17 and 11 patients, respectively). This trend was associated with improveme
nt in the degree of gastritis in non-neoplastic mucosa. Of the four Hp-nega
tive patients, three had signer ring cell carcinoma. Moreover, the numbers
of patients with non-signet ring cell carcinoma also decreased (18, 12 and
7 patients in each period, respectively). These results suggest that Hp-ass
ociated carcinoma has declined gradually in young Japanese.