Published online Nov 14, 2014. doi: 10.3748/wjg.v20.i42.15879
Revised: April 2, 2014
Accepted: June 26, 2014
Published online: November 14, 2014
AIM: To investigate whether dairy product consumption is a risk factor for gastric cancer.
METHODS: We searched the PubMed and Web of Science databases for English-language studies on dairy product consumption and gastric cancer risk that were published between October 1980 and September 2013. One author independently extracted data and assessed study quality. Based on the heterogeneity results, we used either the fixed effects model or the random effects model to compute the summary relative risks and 95% confidence intervals (CIs). We also analyzed subgroups according to the study design, geographic region, sex, and whether there were adjustments for confounders (smoking and drinking) with respect to the sources of heterogeneity.
RESULTS: We found 39 studies that were potentially eligible for inclusion in this meta-analysis, including 10 cohort studies and 29 case-control studies. The summary relative risk for gastric cancer, comparing the highest and lowest dairy product consumption categories, was 1.06 (95%CI: 0.95-1.18). Specific analyses for milk, butter, and margarine yielded similar results, but the results for cheese and yogurt were different. There was significant heterogeneity for all studies (Q = 112.61; P = 0.000; I2 = 67.1%). No publication bias was observed (Egger’s test: P = 0.135; Begg’s test: P = 0.365). There was a nonsignificant association between dairy product consumption and gastric cancer risk in the subgroup analysis for the study design, sex, geographic region, and whether there were adjustments for confounders (smoking and drinking).
CONCLUSION: In our meta-analysis, dairy product consumption was associated with a nonsignificantly increased risk of gastric cancer. However, this result should be verified using large, well-designed prospective studies.
Core tip: Previously published epidemiologic studies have presented inconclusive results on the association between dairy product consumption and gastric cancer risk. Therefore, we performed a meta-analysis to further explore the possibility of an association. To the best of our knowledge, this is the first meta-analysis that explores the association between dairy product consumption and gastric cancer risk. We analyzed the effects of consuming individual dairy product and the total effects of all dairy product on gastric cancer risk, and we conducted subgroup analyses for the study design, sex, region, and adjustment factors. Our study offers new insight into gastric cancer prevention.