The association between diet and bladder cancer risk: a two-sample mendelian randomization

Area of Science:

• Genetics and Epidemiology
• Nutritional Science
• Cancer Research

Background:

• Bladder cancer (BC) is a significant global health concern with complex risk factors.
• Observational studies on diet and BC risk are limited by bias, necessitating robust causal inference methods.
• Dietary patterns (DPs) are increasingly recognized for their potential role in cancer etiology.

Purpose of the Study:

• To investigate the causal relationship between specific dietary patterns and bladder cancer (BC) risk.
• To utilize Two-Sample Mendelian Randomization (TSMR) to overcome limitations of observational studies.
• To identify specific dietary components and overall patterns influencing BC risk.

Main Methods:

• Employed Two-Sample Mendelian Randomization (TSMR) using genetic variants as instrumental variables.
• Analyzed data from UK Biobank GWAS (>500,000 participants) for 14 food items and 4 DPs.
• Utilized inverse-variance weighted (IVW) method with sensitivity analyses (weighted median, MR-Egger, MR-PRESSO) to ensure robustness.

Main Results:

• No causal association found between BC risk and 14 individual foods or two DPs (Low-Caloric, Acquired Diet Patterns).
• Increased adherence to a diet pattern (PC1) rich in whole grains, fruits, and vegetables showed a reduced BC risk (OR: 0.74).
• A Highly Palatable Dietary Pattern (HPDP), characterized by processed, high-calorie foods, was significantly associated with increased BC risk (OR: 2.81).

Conclusions:

• Dietary habits play a crucial role in bladder cancer (BC) prevention.
• Promoting whole-grain, fruit, and vegetable intake (PC1) may offer protective effects against BC.
• Reducing intake of highly palatable, processed foods (HPDP) is recommended for BC risk reduction.
• Further research in diverse populations is needed for targeted BC prevention strategies.