Previous study has raised H’ pylori infection as a suspected biologic risk factor for gastric cancer. Acomparative case-control study involving precancerous lesions and gastric cancer was conducted inYanzhong county

an area with one of the highest rates of gastric cancer in China to study the relatlonshipbetween the H’ pylori infection and gastric cancer. Subjects in the study were all randomly selected Partici-pants of a screening program for gastric cancer sponsored by the Cancer Institute of CAMS in cooPerationwith Yangzhong county Hospital’ Totally

l25 normal controls

lO8 superficial gastritis

l l1 atrophic gas-tritis and 110 gastric cancer patients were included in our study according to endoscopy and pathology re-sult. Status of H. pylori infection was evaluated by measuring Ig G antibody in plasma with ELISA assay.Our result showed Odds ratios of H’ pylori infection were higher among gastritis and cancer groups

4. 5（95 % CI 2. 5

7

. 9） for superficial gastritis

6. 3 （95% CI 3. 4

12） for atrophic gastritis

3. 3 （95 % CI1. 9

5

. 9） for gastric cancer. It was found in our study that consumption of pickled vegetables and drink-ing dirty water increased the relative risk of H’ pylori lnfection for both precancerous lesions and gastriccancer and that H. pylori infection had higher risk of atrophic gastritis and gastric cancer for males and alsohigher risk of atrophic gastritis for olders. Our results strongIy support the casual role played by H. pyloriinfection in the carcinogenic process of gastric mucosa.