Association between dairy products consumption and gastric cancer risk: a meta-analysis

The global burden of gastric cancer remains substantial. While dairy products have been hypothesized to influence gastric cancer risk, epidemiological evidence remains inconsistent. This meta-analysis aimed to evaluate the association between dairy product consumption and the risk of gastric cancer. We systematically searched the PubMed, Web of Science, and other databases from inception to May 2025. Study selection, data extraction, and quality assessment using the Newcastle–Ottawa Scale (NOS) were performed independently by two reviewers. Summary risk ratios, odds ratios (ORs), and 95% confidence intervals (CIs) were pooled using fixed- or random-effects models depending on the level of heterogeneity. Subgroup analyses were conducted by study design, geographic region, and dairy product type. Publication bias was assessed via funnel plots and Egger’s test, and sensitivity analyses were performed. Thirty-four studies (eight cohort, 26 case-control) with high methodological quality (NOS scores 7–9) were included. In cohort studies, dairy consumption showed no significant association with gastric cancer risk compared with nonconsumption. Conversely, case-control studies indicated a modest risk elevation (OR = 1.13, 95% CI = 1.02–1.26). Specific dairy products followed similar design-dependent trends. No significant publication bias was detected, and sensitivity analyses confirmed the robustness of the results. This meta-analysis suggests a positive association between dairy product consumption and gastric cancer risk in case-control studies. The findings underscore the need for further high-quality studies to clarify this relationship.