A significant study has found that long-term heavy alcohol consumption is linked to a higher risk of developing colorectal cancer (CRC). The research, published in the journal Cancer, utilized data from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial to explore the connection between lifetime alcohol intake and the incidence of colorectal adenomas, which are precancerous polyps, as well as invasive cancer.
The findings revealed a clear correlation: individuals with higher lifetime alcohol intake exhibited an increased risk of CRC, particularly rectal cancer. The study also indicated that individuals who ceased alcohol consumption had a lower likelihood of developing early-stage nonadvanced adenomas. This suggests that the cumulative exposure to alcohol over time significantly impacts cancer risk, and reducing alcohol intake might help mitigate early carcinogenic processes.
Understanding the Risk Factors
Colorectal cancer remains a leading cause of cancer mortality, ranked third in incidence across the United States. While overall rates have decreased, diagnoses among adults under 55 are on the rise, highlighting the need to identify and manage modifiable risk factors. The International Agency for Research on Cancer (IARC) has classified alcoholic beverages as carcinogenic, linking them specifically to CRC.
Most previous studies have focused on short-term alcohol consumption, often measuring intake only within the year preceding the study. This approach neglects the long-term effects of alcohol on health, which can span decades. The current study aimed to fill this gap by reconstructing participants’ drinking histories from age 18 onward, thereby providing a comprehensive perspective on alcohol consumption and its relationship to colorectal health.
Study Methodology and Findings
The PLCO Cancer Screening Trial provided a robust dataset, involving 12,327 participants who underwent flexible sigmoidoscopy screening for adenomas and a larger cohort of 88,092 individuals monitored for clinically diagnosed cancer. Participants provided extensive sociodemographic and medical histories, as well as details about their alcohol consumption through a Dietary History Questionnaire.
The data collected allowed researchers to calculate a weighted average of lifetime alcohol intake and categorize participants based on their drinking habits. Current drinkers were classified into groups based on their average weekly consumption, while former drinkers were analyzed separately to mitigate biases related to lifetime abstention.
The results were striking. Those consuming an average of 14 or more drinks per week had a 25% higher risk of developing CRC compared to those who consumed less than one drink per week (hazard ratio, 1.25; 95% CI, 1.01–1.53; p = 0.003). The risk was particularly pronounced for rectal cancer, where heavy drinkers faced nearly double the risk of those in the lowest intake group (hazard ratio, 1.95; 95% CI, 1.17–3.28).
Further, participants identified as consistent heavy drinkers throughout adulthood showed a 91% higher risk of CRC compared to consistent light drinkers (hazard ratio, 1.91; 95% CI, 1.17–3.12). Interestingly, moderate drinking was linked to a lower risk of CRC in some cases, but the study authors cautioned that this finding could result from various confounding factors rather than indicating any protective effect of alcohol.
The study also highlighted the benefits of alcohol cessation. Former drinkers had significantly lower odds of developing nonadvanced adenomas compared to current very light drinkers (odds ratio, 0.58; 95% CI, 0.39–0.84). This suggests that stopping alcohol consumption may reduce the risk at the earliest stages of colorectal disease.
The researchers emphasized that while the observational nature of this study limits causal conclusions, the findings stress the importance of public health messaging. Reducing alcohol intake is crucial not only for immediate health outcomes but also for decreasing long-term cancer risk.
In conclusion, this extensive analysis reinforces the understanding that cumulative lifetime alcohol exposure is a significant factor in colorectal cancer risk. With consistent heavy drinking being a strong risk factor, the study advocates for lifestyle modifications, particularly in adulthood, as a means of cancer prevention. The limitations of reliance on self-reported data and the demographic homogeneity of the study population should be acknowledged as areas for further research.
O’Connell CP et al. (2026). Association of alcohol intake over the lifetime with colorectal adenoma and colorectal cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Cancer, 132(3). DOI: 10.1002/cncr.70201.
