In a comprehensive study, researchers evaluated health information from US adults involved in the National Cancer Institute's Prostate, Long, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, all of whom were cancer-free at the outset. Over a span of two decades, colorectal cancer was identified in 1,679 out of 88,092 participants.
Significant Link Between Heavy Drinking and Cancer Risk
Among those who currently consume alcohol, individuals with a lifetime average of 14 or more drinks per week were categorized as heavy drinkers. This group exhibited a 25% greater risk of developing colorectal cancer compared to those who averaged less than one drink per week throughout their lives. The risk of rectal cancer was even more pronounced, nearly doubling with a 95% increase.
When analyzing drinking patterns over the years, it was discovered that individuals who engaged in heavy drinking for extended periods faced a 91% higher risk of colorectal cancer compared to those who consistently consumed smaller amounts. Interestingly, former drinkers did not show an elevated risk for colorectal cancer and had a lower likelihood of developing noncancerous colorectal growths, known as adenomas, in comparison to current light drinkers. These findings suggest potential benefits of quitting alcohol, although researchers cautioned that data on former drinkers was limited.
Underlying Biological Mechanisms
The connection between alcohol consumption and heightened cancer risk may stem from harmful byproducts formed during alcohol metabolism or the impact of alcohol on gut microbiota. Further studies are necessary to clarify whether these biological mechanisms play a direct role in cancer development.
"Our research is among the first to investigate how alcohol consumption throughout life relates to both colorectal adenoma and cancer risk. Although data on former drinkers were limited, we found it promising that their risk might revert to levels similar to light drinkers," stated co-senior author Erikka Loftfield, PhD, MPH, from the NCI, part of the National Institutes of Health.
