Red meat consumption and stomach cancer risk: a meta-analysis

The association of red meat consumption with the risk of stomach cancer has been reported by many studies, with inconclusive results. We performed a meta-analysis of cohort and case-control studies to provide a quantitative assessment of this association. Relevant studies were identified by searching PubMed and Embase before December 2013 without restrictions. A total of 18 studies involving 1,228,327 subjects were included in this meta-analysis. Summary relative risks were estimated using random effects models. The pooled relative risks of gastric cancer were 1.37 (95 % CI 1.18-1.59) for the highest versus lowest categories of red meat intake with significant heterogeneity among studies (P (heterogeneity) < 0.001, I (2) = 67.6 %). When stratified by the study design, the significant associations were observed in population-based case-control studies (RR 1.58; 95 % CI 1.22-2.06; P (heterogeneity) < 0.001, I (2) = 73.0 %) and hospital-based case-control studies (RR 1.63; 95 % CI 1.38-1.92; P (heterogeneity) = 0.284, I (2) = 19.1 %). However, no association was observed among cohort studies (RR 1.00; 95 % CI 0.83-1.20; P (heterogeneity) = 0.158, I (2) = 33.9 %). The significant association was also presented in the subgroup analysis by geographic area (Asia, Europe), publication year (a parts per thousand yen2000), sample size (< 1,000, a parts per thousand yen1,000) and quality score (< 7 stars, a parts per thousand yen7 stars). The dose-response analysis associated every 100 g/day increment in red meat intake with a 17 % increased gastric cancer risk (RR 1.17; 95 % CI 1.05-1.32). A linear regression model further revealed that the risk of gastric cancer increased with increasing level of red meat consumption. Increased intake of red meat might be a risk factor for stomach cancer. Further larger prospective studies are warranted to verify this association.