Association between NAFLD and liver cancer: A two-sample Mendelian randomization study

Area of Science:

• Hepatology and Gastroenterology
• Genetics and Epidemiology

Background:

• Observational studies indicate a link between nonalcoholic fatty liver disease (NAFLD) and liver cancer.
• The causal relationship between NAFLD and liver cancer remains uncertain.

Purpose of the Study:

• To investigate the potential causal effect of NAFLD on liver cancer risk using a 2-sample Mendelian randomization (MR) approach.
• To provide genetic evidence supporting or refuting a causal link between NAFLD and liver cancer.

Main Methods:

• Utilized summary statistics from genome-wide association studies for NAFLD and liver cancer.
• Employed various MR methods (inverse-variance weighted, MR-Egger, weighted median) with rigorous selection of instrumental variables.
• Conducted sensitivity and power analyses to assess the robustness and limitations of the findings.

Main Results:

• All four MR analyses revealed a significant positive causal association between NAFLD and an increased risk of liver cancer (OR > 1, P < .001).
• Sensitivity analyses confirmed the absence of significant heterogeneity or horizontal pleiotropy, supporting the validity of the findings.
• The study identified a genetically predicted causal relationship, consistent across liver cancer subtypes, but noted insufficient statistical power for precise effect estimation.

Conclusions:

• This study presents the first MR evidence suggesting a causal role of NAFLD in liver cancer development.
• Findings support the hypothesis that NAFLD is a risk factor for liver cancer, underscoring the importance of early NAFLD management.
• Future large-scale genome-wide association studies are necessary to enhance statistical power and refine the causal effect estimation.