Preliminary Exploration Of The Interaction Between Helicobacter Pylori Infection And High Salt Intake In The Occurrence Of Gastric Cancer

Objective To explore and analyze whether there is an interaction between Helicobacter pylori infection and high salt intake in the occurrence of gastric cancer and the strength of the interaction.This will help identify key intervention groups and achieve precise prevention and control of gastric cancer.Methods In the first part,Chinese and English literatures on the interaction between Helicobacter pylori and high salt intake in gastric cancer were systematically searched from Embase,Web of Science,Pub Med,CNKI and Wanfang database.The retrieval time is from the establishment to June 17,2020.Literature was screened according to the established inclusion and exclusion criteria.The Newcastle-Ottawa scale was used to evaluate the quality of the included literatures and extract relevant information.Then the interaction between the two was preliminarily judged through qualitative and quantitative systematic evaluation.The second part used a 1:2 matched case control study.All respondents were given questionnaires,body measurements,Helicobacter pylori tests and salty preference measure by specially trained investigators.The risk factors of gastric cancer were analyzed by conditional Logistic regression model.When other risk factors were not considered,the interaction between H.pylori and high salt intake was analyzed using crossover analysis tables.When considering the other risk factors,the product of Helicobacter pylori and high salt intake index and other risk factors are included in the regression model to analyze the multiplicative interaction.After adjusting for other factors,the covariance and regression coefficient of H.pylori and high salt intake indicators were calculated,and then substituted into the Excel calculation table prepared by Andersson et al.,to obtain the estimated values of RERI,AP and S and their 95%CI to judge the additive interaction.Results In the first part,a total of 3849 literatures were retrieved,including 44 literatures in Chinese and 3805 literatures in English.A total of 8 English articles,including 7 case-control studies and 1 cohort study,were selected after eliminating duplicates,inconsistencies and reviews.The included literatures only used regression models to analyze the multiplicative interactions and did not analyze the additive interactions.The results of 5 of the literatures showed an interaction between the two.Results of two case-control studies showed that high salt intake was a risk factor for gastric cancer only in the helicobacter pylori positive group.Results of two case-control studies showed an increased risk of gastric cancer in people who were Helicobacter pylori positive and on a high-salt diet.Results of a cohort study showed a synergistic effect between Helicobacter pylori positivity and a high salt intake in patients with atrophic gastritis.Results of the other three case-control studies showed no interaction between the two.META analysis was performed on 4 case-control studies that provided detailed information.The random effects model is used to combine effect sizes.When Helicobacter pylori was negative,the OR of high salt intake and gastric cancer was 0.40(95%CI: 0.08～1.95).When Helicobacter pylori was positive,the OR of high salt intake and gastric cancer was 3.01(95% CI:0.97-9.36).In the second part,the case group and the control group were equally comparable in terms of age,gender,ethnicity,urban and rural areas,educational level,and marital status.Conditional Logistic regression analysis showed that people with H.pylori infection(OR=2.853),frequent consumption of pickled vegetables(OR=4.003),frequent consumption of processed meat(OR=2.983),frequent consumption of fried food(OR=5.486),alcohol consumption(OR=1.776),family history of cancer(OR=2.991)and frequent anger(OR=3.790)had higher risk of gastric cancer.When other risk factors were not taken into account,there was no interaction between H.pylori and the four high salt intake indicators.After adjusting for other risk factors,regression analysis showed that there was no multiplicative interaction between H.pylori and regular consumption of preserved vegetables and processed meat.The results of Excel spreadsheet showed that there was no additive interaction between Helicobacter pylori and salted vegetables and processed meat.Conclusion Part I Systematic review: There are few documents analyzing the interaction between Helicobacter pylori and high salt intake in the occurrence of gastric cancer.Due to different variable measurement methods and different criteria for judging "high salt",the heterogeneity of the literature is large.Some previous studies have shown that there is an interaction between the two,and some have shown no interaction between the two.Part II Case Control Study: Helicobacter pylori infection,regular consumption of preserved vegetables,regular consumption of processed meat,regular consumption of fried foods,alcohol consumption,family history of cancer,and frequent anger are risk factors for gastric cancer.There was neither multiplicative interaction nor additive interaction between H.pylori and regular consumption of pickled vegetables and processed meat.Due to the small sample size and recall bias,this study can only be a preliminary exploration of the interaction between Helicobacter pylori and high-salt diet.In the next step,it is necessary to find indicators that can comprehensively judge the "high salt intake",and conduct a large-sample prospective study for further demonstration.