Objective: A comprehensive overall review of gastric cancer (GC) risk and protective factorsis a high priority, so we conducted the present study.
Methods: Systematic searches in common medical electronicdatabases along with reference tracking were conducted to include all kinds of systematic reviews (SRs) aboutGC risk and protective factors. Two authors independently selected studies, extracted data, and evaluated themethodological qualities and the quality of evidence using R-AMSTAR and GRADE approaches.
Results: Betacarotenebelow 20 mg/day, fruit, vegetables, non-fermented soy-foods, whole-grain, and dairy product were GCprotective factors, while beta-carotene 20 mg/day or above, pickled vegetables, fermented soy-foods, processedmeat 30g/d or above, or salty foods, exposure to alcohol or smoking, occupational exposure to Pb, overweightand obesity, helicobacter pylori infection were GC risk factors. So we suggested screening and treating H. pyloriinfection, limiting the amount of food containing risk factors (processed meat consumption, beta-carotene,pickled vegetables, fermented soy-foods, salty foods, alcohol), stopping smoking, avoiding excessive weight gain,avoidance of Pb, and increasing the quantity of food containing protective components (fresh fruit and vegetables,non-fermented soy-foods, whole-grain, dairy products).
Conclusions: The conclusions and recommendationsof our study were limited by including SRs with poor methodological bases and low quality of evidence, so thatmore research applying checklists about assessing the methodological qualities and reporting are needed for thefuture.