Helicobacterpylori infection and gastric cancer:evidence from a retrospective cohort study and nested case-control study in China

AIM:To explore the association between He/icobacterpylori(Hp)infection and risk of gastric cancer in China.METHODS:Utilizing gastroendoscopic biospsy tissue banksaccumulated from1980 to1988 in Shandong,Zhejiang,andJiangsu,where stomach cancer incidence was high,duringstomach cancer screening conducted by Health ScienceCenter of Peking University,School of Medicine of ZhejiangUniversity,and Zhongshan Hospital of Fudan University.Warthin Starry silver staining method was applied todetermine H.pylori infection status of biopsies collectedduring gastroendoscopic examination.In the retrospectivestudy,the subjects were divided into two cohorts,theexposure cohort was positive H.pylori infection,and thenon-exposure cohort was negative.Death from stomachcancer was determined as the outcome of the study.Logisticregression and Cox regression were applied to analyze theassociation between Helicobacterpyloriinfection and gastriccancer risk.In the nested case-control study,there were 28deaths from gastric cancer in the fields of Muping,Shandongprovince,and Zhoushan,Zhejiang provinces.4 controls werematched to each case on the basis of age(±5 years old),sex,residential place at the same time entered into thestudy.Conditional logistic regression analysis was used toanalyze the data.RESULTS:There were a total of 2 719 subjects(male 1 399,female 1 320)with gastroendoscopic biopsies storedavailable treated as a cohort.H.pylori positive cohortincluded 1 671 subjects(61.5 %)and H.pylori negativecohort 1 048 subjects(38.5 %).These subjects were followed up for 1-19 years,averaged 10.88 years.Theoutcome of death from stomach cancer in the exposurecohort was 33,and in the non-exposure cohort 11.Afteradjustment for age and sex,RR=1.9850(P=0.0491),95 %CI was 1.0026,and 3.9301.The results of conditionallogistic regression showed an OR of 4.467 and 95 % CI of1.161,and 17.190 for the nested case control study.CONCLUSION:The results from the retrospective cohortstudy and the nested-case control study on the associationof H.pylori infection and gastric cancer in China suggestedthat Helicobacter pylori infection might increase the risk ofstomach cancer,