Association of Red Meat Intake and Colorectal Cancer among East-Asians: A Systematic Review and Meta-analysis of Observational Studies Performed between 2011-2021.

Background and aims: Colorectal cancer has the third highest incidence and second highest mortality among all cancers worldwide. Although numerous studies investigating the associations between high red meat intake and risk of colorectal cancer have been published, the association between the intake of red meat and the risk of colorectal cancer in Asians remains unclear. We performed a systematic review and meta-analysis of cohort and case-control studies to estimate the association between red meat intake and colorectal cancer incidence rate between 2011-2021.

Method: We searched PubMed database from 1 Jan 2011 to 21 July 2021. Prospective cohort studies and nested case-control studies that reported results on the association between red meat consumption and colorectal cancer were included in the meta-analysis. The outcome of interest was the association between the intake of red meat and the risk of colorectal cancer. We performed a meta-analysis to calculate the odds ratios (OR) with 95% confidence intervals (CI).

Results: A total of 5 studies enrolling 48,158 participants were included. The results showed no significant association between red meat intake and colorectal cancer risks (OR=1.38; 95%CI: 0.98-1.93). The aspect of the corresponding funnel plot suggested the presence of significant publication bias. Egger's test confirmed the significant asymmetry of the funnel plot (t = 9.3024, p = 0.0026).

Conclusions: Contrary to many other meta-analyses, our study showed that intake of red meat was not associated with increased risk of colorectal cancer in East-Asians from China, Japan and South Korea. However, due to the limited number of included papers and the lack of confounders adjustments, our results warrant cautious interpretations.