The association between alcohol intake and colorectal cancer may vary secondary to single nucleotide polymorphisms (SNPs) in two pathways related to alcohol intake.
375 cases of colorectal cancer were identified among 38,373 participants of the Japan Public Health Center-based prospective Study (JPHC Study) who had returned a baseline questionnaire, reported no diagnosis of any cancer and provided blood samples.
For each case, two controls were selected on matching variables. Logistic regression models were used to determine matched Odds Ratios (OR) and 95% Confidence Intervals (CI) for the association between alcohol consumption, genetic polymorphisms of enzymes in the alcohol- and folate metabolic pathways (e.g. methylenetetrahydrofolate reductase (MTHFR) rs1801133) and colorectal cancer risk.
Compared to never/occasional drinkers, moderate to heavy alcohol use was associated with colorectal cancer (OR = 2.12, 95% CI, 1.34-3.36). When compared to the CC genotype, the MTHFR rs1801133 CT/TT genotype was inversely associated with colorectal cancer (OR = 0.72, 95% CI, 0.54-0.97). Never/occasional consumers of alcohol with the MTHFR rs1801133 CT/TT genotype were at a reduced risk of colorectal cancer compared to never/occasional drinkers with the CC genotype (OR = 0.68, 95% CI, 0.47-0.98).
The results indicate that the folate pathway is likely to be involved in alcohol-related colorectal cancer development.
Source: Alcohol consumption, genetic variants in the alcohol- and folate metabolic pathways and colorectal cancer risk: the JPHC Study. Svensson T, Yamaji T, Budhathoki S, Hidaka A, Iwasaki M, Sawada N, Inoue M, Sasazuki S, Shimazu T, Tsugane S. Sci Rep. 2016 Nov 9;6:36607. doi: 10.1038/srep36607.