Excessive alcohol use was strongly associated with an increased risk for colorectal cancer (CRC), regardless of genetic risk, in a large population-based study published online in The Lancet’s eClinical Medicine journal.
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,” wrote 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, Germany, and colleagues.
Investigators set out to assess the association of alcohol intake with overall CRC risk, early-onset CRC (EOCRC, <55 years) risk, and late-onset CRC (LOCRC, ≥55 years) risk at different levels of polygenic risk score (PRS), and to quantify the impact of drinking alcohol using the recently developed metric Genetic Risk Equivalent (GRE).
In total, 5104 (60.3% men; median age, 69 years) cases with CRC and 4131 (61.5% men; median age, 70 years) control cases were included in the analysis. Participants self-reported their daily alcohol use, which was categorized as abstinent (0 g), low (<12 g), low-moderate (12-25 g) moderate-high (25-50 g) or high (≥50 g).
Results showed that lifetime abstaining, moderate-high, and high alcohol consumption were significantly associated with a 16%, 22%, and 51% higher risk, respectively, of CRC when compared to lifetime low alcohol consumption. Similar associations with CRC risk applied to recent alcohol consumption, according to Brenner et al.
Brenner and colleagues also reported that an average lifetime alcohol intake of at least 25 g per day was associated with a 1.8-fold (95% confidence interval [CI], 1.2-2.8) increased risk for EOCRC and a 1.3-fold (95% CI, 1.1-1.4) increased risk for LOCRC.
PRS was independently associated with both EOCRC and LOCRC, with highest risks observed among heavy drinkers with high PRS, according to the study. Researchers noted that the estimated impact of high lifetime alcohol consumption on EOCRC was equivalent to the effect of having 47 percentiles higher PRS (GRE, 47; 95% CI, 12–82), which was stronger than the impact on LOCRC (GRE, 18; 95% CI, 8–29).
Investigators also noted that in subgroup analyses, abstaining from wine, beer, and liquor was significantly associated with a 21%, 23%, and 11% higher risk of CRC when compared to the reference of pure ethanol, respectively.
“Further research is needed to derive more precise estimates of the impact of various patterns of alcohol consumption in combination with PRS, other lifestyle factors, and comorbidities across various ethnic groups in the total population and young adults in particular,” concluded authors.