Association between red and processed meat consumption and colorectal cancer risk : a comprehensive meta-analysis of prospective studies

Increasing evidence suggests that red and processed meat consumption may elevate the risk of colorectal cancer (CRC), yet the magnitude and consistency of this association remain debated. This meta-analysis aims to quantify the relationship between red and processed meat intake and the risk of CRC, colon cancer, and rectal cancer using the most comprehensive set of prospective studies to date. We conducted a comprehensive search in PubMed, Web of Science, Cochrane Library, Embase, and Google Scholar databases from 1990 to November 2024, to identify relevant prospective studies examining red, processed, and total meat consumption in relation to colorectal, colon, and rectal cancer risk. Hazard ratios (HR) and 95% confidence intervals (CI) were extracted for each study and pooled using a random-effects model to account for variability among studies. Statistical evaluation was executed using the online platform MetaAnalysisOnline.com. A total of 60 prospective studies were included. Red meat consumption was associated with a significantly increased risk of colon cancer (HR = 1.22, 95% CI 1.15-1.30), colorectal cancer (HR = 1.15, 95% CI 1.10-1.21), and rectal cancer (HR = 1.22, 95% CI 1.07-1.39). Processed meat consumption showed similar associations with increased risk for colon cancer (HR = 1.13, 95% CI 1.07-1.20), colorectal cancer (HR = 1.21, 95% CI 1.14-1.28), and rectal cancer (HR = 1.17, 95% CI 1.05-1.30). Total meat consumption also correlated with an elevated risk of colon cancer (HR = 1.22, 95% CI 1.11-1.35), colorectal cancer (HR = 1.17, 95% CI 1.12-1.22), and rectal cancer (HR = 1.28, 95% CI 1.10-1.48). This meta-analysis provides robust evidence that high consumption of red and processed meats is significantly associated with an increased risk of colorectal, colon, and rectal cancers. These findings reinforce current dietary recommendations advocating for the limitation of red and processed meat intake as part of cancer prevention strategies.