Association of meat consumption with the risk of gastrointestinal cancers: a systematic review and meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of prospective cohort studies
PubMed 37612616 · doi:10.1186/s12885-023-11218-1
What was done
A systematic review and random-effects meta-analysis of prospective cohort studies from PubMed, EmBase, and Cochrane Library through February 2023. The authors examined associations between red meat, processed meat, and total meat intake and risk of gastrointestinal cancers (esophageal, gastric, colorectal, colon, rectal, pancreatic, and hepatocellular). Pooled relative risks (RR) with 95% confidence intervals (CI) were calculated using inverse variance weighting.
What was found
Across 40 cohorts with 3,780,590 individuals: - High red meat intake was associated with increased risk of colorectal cancer (CRC: RR 1.09, 95% CI 1.02–1.16, P = 0.007) and colon cancer (CC: RR 1.13, 95% CI 1.03–1.25, P = 0.011). - High processed meat intake was associated with increased risk of CRC (RR 1.19, 95% CI 1.13–1.26, P < 0.001), CC (RR 1.24, 95% CI 1.13–1.26, P < 0.001), and rectal cancer (RC: RR 1.24, 95% CI 1.08–1.42, P = 0.002). - High total red and processed meat intake was associated with increased risk of CRC (RR 1.13, 95% CI 1.06–1.20, P < 0.001), CC (RR 1.17, 95% CI 1.04–1.33, P = 0.012), and RC (RR 1.20, 95% CI 1.04–1.39, P = 0.016). - Subgroup analysis showed weaker associations in cohorts with high adjustment levels for gastric cancer and RC, while follow-up >= 10 years showed stronger associations for processed meat with RC and hepatocellular carcinoma. Numeric risk estimates for esophageal, gastric, pancreatic, and liver cancers were not reported in the abstract.
Why it matters
Synthesizes data from nearly 3.8 million people to confirm a consistent, modest observational association between higher red and processed meat intake and colorectal cancer risk.
Limits
Based on observational cohorts subject to residual dietary and lifestyle confounding and self-reported intake errors. Associations attenuated in studies with higher adjustment levels. Specific intake cutoffs, cooking methods, and numerical outcomes for upper GI cancers are not detailed in the abstract.