J-shaped association between moderate consumption of alcoholic beverages and colorectal cancer risk

This large meta-analysis found a J-shaped dose-response pattern between the association of consuming alcoholic beverages and the risk of colorectal cancer.

Colorectal cancer (CRC) is the 3rd most commonly diagnosed cancer worldwide. Consumption of alcoholic beverages is an established risk factor for CRC. While studies have consistently reported an increased risk among heavy drinkers, the association at light and moderate levels of alcohol intake are less clear.

In this study, the risk of colorectal cancer among light to moderate drinkers (up to 28g of alcohol/day which is the equivalent of approx. 2-3 glasses of wine) was slighty reduced compared to non or occasional drinkers. However, with heavy drinking (more than 42 g/d) the risk of CRC increased by 25%. The authors explained their findings by the possible role of moderate alcohol intake in reducing inflammation processes and DNA damage in the body.

What does it mean?

Alcohol is an established risk factor for CRC and linking heavy drinking to an increased risk of CRC has been consistently reported in previous studies, however, the impact of light to moderate drinking has been inconsistent. This study provides further evidence for a J-shaped relationship between the intake of alcoholic beverages and CRC risk at various levels of drinking.

Even when exluding former drinkers from lifetime abstainers in a subset of studies, the same protective association with light to moderate drinking was found.

There was no differentiation between the various alcoholic beverages and the drinking pattern was not determined.

McNaab S et al, Meta-analysisA meta-analysis is a method of summarizing the results of the same research purpose and comprehensiv... of 16 studies oft he association of alcohol with colorectal cancer, Int J Cancer:00, 2019, https://www.doi:10.1002/ijc.32377

Definition:

Light to moderate consumption: up to 2 drinks/day = 28g of alcohol

Heavy consumption: 2-3 drinks/day

Very heavy consumption: > 3 drinks/day

1 drink = 14 g of alcohol