Purpose: Excessive alcohol consumption has been linked to an increased risk of colorectal cancer (CRC). We evaluated the association between alcohol-related genetic variants and CRC risk.
Materials and methods: The study cohort consisted of 5,435 CRC cases and 3,553 population-based cancer-free controls. Genotype data were generated from germline DNA using the Infinium OncoArray-500K BeadChip in 2,535 cases and 2,287 controls and the Infinium Multi-Ethnic Global BeadChip in 2,900 cases and 1,266 controls. The associations between aldehyde dehydrogenase 2 (ALDH2) rs671 and alcohol dehydrogenase 1B (ADH1B) rs1229984 polymorphisms and CRC risk were assessed using multivariate logistic regression analyses.
Results: Compared with the major homozygous ALDH2 genotype (GG), heterozygous or minor homozygous ALDH2 genotype (GA or AA, related to a low alcohol consumption) was significantly associated with a reduced risk for CRC in men (odds ratio [OR], 0.78; 95% confidence interval [CI], 0.68 to 0.90), but not in women (OR, 0.70; 95% CI, 0.47 to 1.05). A stronger association was found among regular drinkers (OR, 0.58; 95% CI, 0.47 to 0.71 in men and OR, 0.33; 95% CI, 0.18 to 0.58 in women). No association of CRC risk with ADH1B rs1229984 genotype was found. The association between alcohol-related combined genotypes and risk of CRC was significant (p for linear=0.001). The combined genotype with the highest genetically predicted alcohol consumption (ALDH2 rs671 GG and ADH1B rs1229984 AG/GG) was associated with a high risk for CRC (OR, 1.35; 95% CI, 1.11 to 1.63).
Conclusion: Our study provides strong evidence for a possible causal association between alcohol consumption and CRC risk.
Keywords: Alcohol; Alcohol dehydrogenase 2; Aldehyde dehydrogenase 2; Colorectal neoplasm.