Processed meat, red meat, white meat, and digestive tract cancers: A two-sample Mendelian randomization study

Area of Science:

• Genetics
• Epidemiology
• Nutritional Science

Background:

• Observational studies show inconsistent associations between meat consumption and digestive tract cancers (DCTs).
• The causal relationship between meat intake and DCTs remains unclear, necessitating further investigation.

Purpose of the Study:

• To investigate the causal effect of processed, red, and white meat intake on various digestive tract cancers.
• To clarify the role of meat consumption in the etiology of esophageal, stomach, liver, biliary tract, pancreatic, and colorectal cancers.

Main Methods:

• Two-sample Mendelian randomization (MR) using genome-wide association studies (GWAS) data.
• Primary analysis with inverse-variance weighting (IVW) and complementary MR-Egger analysis.
• Sensitivity analyses including MR-PRESSO and multivariable MR (MVMR) to assess robustness and explore mediation.

Main Results:

• Processed meat intake showed a causal association with an increased risk of colorectal cancer (OR = 2.12, P = 0.031).
• This association remained significant in MVMR analysis (OR = 3.85, P = 0.030) after accounting for other meat types.
• No causal effects were found for processed meat on other DCTs, nor for red or white meat on any DCTs.

Conclusions:

• Processed meat consumption is causally linked to an increased risk of colorectal cancer.
• Red and white meat intake do not appear to have a causal relationship with digestive tract cancers.