Alcohol intake significantly influences colorectal cancer risk

High alcohol consumption was significantly associated with an increased risk for colorectal cancer, regardless of genetic risk, according to findings published in The Lancet’s eClinical Medicine.

The findings imply “that the impact of avoiding heavy drinking can be as strong as having a substantially lower genetically determined increased colorectal cancer risk ... which further underscores the role of cutting down on alcohol in colorectal cancer prevention and may be helpful for more effective risk communication,” Hermann Brenner, MD, MPH, a professor of epidemiology at Heidelberg University and head of the clinical epidemiology and aging research division at the German Cancer Research Center in Heidelberg, and colleagues wrote.

In a population-based, case-control study, Brenner and colleagues assessed the association between alcohol consumption and colorectal cancer across polygenic risk score levels for 140 colorectal cancer-related loci. In total, 4,131 control cases and 5,104 colorectal cancer cases were evaluated. Among the participants with cancer, 60.3% were men with a median age of 69 years.

The researchers used Genetic Risk Equivalent (GRE) scores to compare the effects of alcohol consumption and polygenetic risk scores on cancer risk. Participants self-reported their alcohol consumption, which were categorized as abstinent (0 g/d), low (< 12 g/d), low-moderate (12g/d to 25 g/d) moderate-high (25 g/d to 50 g/d) or high (50 g/d) consumption.

Alcohol consumption

Overall, a majority (41.1%) of participants with colorectal cancer had low lifetime alcohol consumption and low recent alcohol consumption (30.1%).

Brenner and colleagues reported that abstinent, moderate-high and high lifetime alcohol consumption were significantly associated with a 16%, 22% and 51% higher risk for colorectal cancer compared with low lifetime alcohol consumption. Similar associations with cancer risk applied to recent alcohol consumption.

The data further showed that an average lifetime alcohol consumption of at least 25 g daily was associated with a 1.8-fold (95% CI, 1.2-2.8) increased risk for early-onset cancer and a 1.3-fold (95% CI, 1.1-1.4) increased risk for late-onset cancer.

Polygenic risk

The relationships between dose of alcohol consumption and cancer risk were similar for participants with low and high polygenic risk scores, according to the researchers.

Among participants with high polygenic risk scores, lifetime abstinent, low, low-moderate, moderate-high and high alcohol consumption were associated with a 2.1-, 1.7-, 1.8-, 2.2- and 2.6-fold increased risk for cancer compared with low lifetime alcohol consumption among participants with low polygenic risk scores, Brenner and colleagues reported. Similar associations persisted with recent alcohol consumption.

Moreover, high polygenic risk was significantly associated with a 1.9-fold increased risk for colorectal cancer, as well as early- and late-onset colorectal cancer, compared with participants with low polygenic risk.

Polygenic risk was independently associated with both early- and late-onset cancer, with the highest risk among those with high polygenic risk who drank heavily. Specifically, participants with high polygenic risk who drank at least 25 g of alcohol daily had a 3.4-fold (95% CI, 2-6) increased risk for early onset cancer and a 2.3-fold (95% CI, 2-2.8) increased risk for late-onset cancer compared with participants with low polygenic risk and low alcohol consumption. This association was similar for recent alcohol consumption, Brenner and colleagues reported.

While long-term high consumption of beer and liquor was associated with an increased risk for colorectal cancer, long-term high consumption of wine was not, according to the researchers.

Overall, the impact of high lifetime alcohol consumption on early-onset colorectal cancer was about equal to having 47 percentiles higher polygenic risk (GRE = 47; 95% CI, 12-82), which was stronger than the impact on late-onset cancer (GRE = 18; 95% CI, 8-29).

“Further research is needed to derive more precise estimates of the impact of various patterns of alcohol consumption in combination with polygenic risk score, other lifestyle factors and comorbidities across various ethnic groups in the total population and young adults in particular,” the researchers wrote.