Alcohol intake and risk of alcohol-related cancer
A new study from Australia found that heavy drinking in early adulthood may increase the risk for alcohol-related cancers, including colorectal cancer (CRC), even after drinking decreases or stops entirely in middle age.
Alcohol is a known risk factor for CRC – the 2018 World Cancer Research Fund and American Institute for Cancer Research report (“Diet, nutrition, physical activity and colorectal cancer”) states that there is strong evidence to show that consuming approximately 2 or more alcoholic drinks per day increases the risk of developing CRC1. The precise mechanisms that drive the association between alcohol consumption and cancer development are not fully understood, though a large body of evidence has shown that the toxic by-product produced in the body when alcohol is consumed – acetaldehyde – interferes with DNA synthesis and repair, and therefore may contribute to the development of cancer.
In the study, researchers analyzed individuals’ lifetime drinking trajectories and risk for alcohol-related cancer using data from the Melbourne Collaborative Cohort Study which involved 22,756 women and 15,701 men. Heavy drinking was defined as an average alcohol intake of at least 60g/day, which is about the equivalent of 6 standard alcoholic drinks. For men, compared to non-drinkers, heavy drinking trajectories were associated with an increased overall risk for alcohol-related cancer, with the strongest associations for the early decreasing heavy trajectory (individuals who started as heavy drinkers at age 20-39 (≥ 60 g/day) and continued to cut down their intake over time until arriving at stable, light drinking habits by age 60-69), and the late decreasing heavy trajectory (individuals who started drinking ≥ 60 g/day in their 20s and began to decrease from age 60-69).
For women, the increasing moderate trajectory (individuals who consumed around 20g/day (2 alcoholic drinks) at age 20-29 and gradually increased their alcohol intake over time to consume close to 40g/day (4 alcoholic drinks) by age 50-59) was associated with a greater risk for alcohol-related cancer overall. The increasing moderate trajectory in women was similarly associated with an increased risk for breast and colorectal cancer.
These findings demonstrate the impact of heavy drinking on cancer risk even when drinking decreases or stops completely later in life. The study investigators concluded that while the WCRF/AICR report underlines the importance of limiting alcohol intake during middle age to prevent cancer, the study findings highlight the additional importance of limiting alcohol intake during early adulthood.
Take away message:
While there is a known association between alcohol consumption and the development of cancer, a recent study highlights the association between cancer and alcohol consumption not just in middle age but during early adulthood.