A causal relationship between alcohol intake and type 2 diabetes mellitus: A two-sample Mendelian randomization study

Area of Science:

• Genetics
• Epidemiology
• Metabolic Diseases

Background:

• Investigating the causal link between alcohol consumption and type 2 diabetes mellitus (T2DM) risk.
• Utilizing the Korean Genomic Epidemiology Study cohort for robust analysis.

Purpose of the Study:

• To determine if alcohol intake causally influences T2DM risk using Mendelian randomization.
• To quantify the association between high alcohol intake and T2DM development.

Main Methods:

• Two-sample Mendelian randomization (MR) analysis incorporating GWAS data.
• Instrumental variables identified for alcohol intake (p < 5 × 10⁻⁸, r² < 0.001).
• Inverse-variance weighted, weighted median, and MR-Egger methods applied; sensitivity analyses conducted.

Main Results:

• High alcohol intake (≥20 g/day) showed a causal association with increased T2DM risk via inverse-variance weighted and weighted median methods.
• No significant heterogeneity or horizontal pleiotropy detected, indicating robust findings.
• Leave-one-out analysis confirmed the causal association was not driven by a single genetic variant.

Conclusions:

• Evidence supports a causal relationship between heavy alcohol consumption and an elevated risk of developing T2DM.
• Findings highlight the importance of moderating alcohol intake for diabetes prevention.