RESUMEN
Objective To understand the application and research progress of Mendelian randomization (MR) studies related to gastric cancer and provide a scientific basis for gastric cancer prevention. Methods Published studies on risk factors of gastric cancer based on MR methods were searched in PubMed, Web of Science, EMBASE, CNKI, and WANFANG DATA from the establishment of each database to November 19th, 2022. Two researchers examined the eligibility of studies, extracted key information, and assessed the research quality independently. Results A total of 30 publications published from 2016 to 2022 were included in the study, and 20 were judged to be of high quality. These studies examined the relationship between behaviors and lifestyle factors, anthropometric characteristics, indicators of biological exposure, and other pathological conditions and gastric cancer, and the results suggest potential causal associations between smoking and other factors and the risk of gastric cancer. Conclusion Previous MR studies extensively investigated the causal association between internal and external exposures or traits and gastric cancer and provided positive evidence of gastric cancer etiology. However, MR studies may be subject to methodological limitations. Interpretation of results needs to be approached with caution, which necessitates the integration with biological plausibility and evidence from observation studies.