Association between dried fruit intake and pan-cancers incidence risk: A two-sample Mendelian randomization study

Area of Science:

• Nutritional Epidemiology
• Genetic Epidemiology
• Cancer Research

Background:

• Observational studies suggest a link between dried fruit intake and cancer incidence, but confounding factors complicate interpretation.
• A Mendelian randomization (MR) study was designed to investigate the causal relationship between dried fruit intake and 11 site-specific cancers.

Purpose of the Study:

• To determine the causal effect of dried fruit intake on the incidence of 11 site-specific cancers using a two-sample MR approach.
• To leverage genetic variants as instrumental variables for dried fruit intake to mitigate confounding factors.

Main Methods:

• Utilized 43 single nucleotide polymorphisms (SNPs) strongly associated with dried fruit intake as instrumental variables (IVs).
• Employed inverse-variance weighted (IVW) and weighted median (WM) methods for causal inference, with sensitivity analyses for heterogeneity and pleiotropy.
• Validated findings using summary statistics from FinnGen and UK Biobank databases, incorporating multivariable MR to adjust for covariates like BMI and fresh fruit intake.

Main Results:

• Significant inverse associations were found between dried fruit intake and oral cavity/pharyngeal, lung (including squamous cell lung cancer), breast, ovarian, and pancreatic cancers.
• No significant causal effects were observed for lung adenocarcinoma, endometrial, thyroid, prostate, bladder, or brain cancers.
• Validation and multivariable MR analyses confirmed the protective association for lung and breast cancers, underscoring the robustness of the findings.

Conclusions:

• Dried fruit intake demonstrates a potential protective effect against several site-specific cancers, suggesting a role in primary cancer prevention.
• Recommendations include health education and dietary adjustments incorporating dried fruits to potentially reduce cancer incidence.