International Scientific Forum on Alcohol Research Critique 112: Relation of Alcohol Intake to Risk of Dying from Cancer

There have been many papers relating alcohol intake to specific types of cancer. It is clear that heavy drinking is associated with an increase in the risk of most upper aero-digestive cancers (eg, cancer of the mouth, pharynx, larynx), and even moderate drinking has been associated with a slight increase in the risk of breast cancer. On the other hand, the risk of thyroid cancer, lymphoma, renal cancer, and certain other cancers has been shown to be lower among moderate drinkers than among abstainers.

There have been few studies describing the relation between varying levels of alcohol consumption and the total risk of cancer. The present paper presents a meta-analysis relating alcohol intake to all cancer mortality, with data on more than 48,000 cancer deaths reported in 18 prospective cohort studies.

Surprisingly, the analyses demonstrated a J-shaped curve for alcohol and cancer. Light drinkers showed a statistically significant 9% lower risk, moderate drinkers showed no effect, and heavier drinkers showed a 32% increased risk of all cancer mortality.

Forum reviewers had some concerns about the conclusions of the paper, based on some discrepancies in the text, the lack of data on drinking pattern, no beverage-specific results, or data on different types of cancer. Nevertheless, as expected, the reported average consumption of 50 or more grams of alcohol per day (equivalent to 4 or more typical drinks each day) was associated with an estimated 32% increased risk of dying from cancer. 

However, there was no increase in the estimated risk of cancer death for subjects classified as “moderate” drinkers (defined by the authors using a wide range of intake: 12.6 to 49.9 grams/day, the equivalent of up to approximately 4 or more typical drinks). Further, Forum members were surprised that a slight but statistically significant decrease in cancer mortality risk was seen for “light” drinkers (those reporting an average of = 12.5 grams/day, or about one typical drink). Forum members appreciated that misclassification of cause of death or residual confounding could have contributed to this latter result.

It is especially important that the only significant increase in risk in cancer mortality among the almost 50,000 cancer deaths reported in this meta-analysis was for consumers of 50 grams or more of alcohol. This suggests strongly that the overall risk of cancer mortality related to alcohol consumption is primarily (perhaps almost exclusively) from heavier drinking. Certainly, the findings from this study do not support the premise that “any amount of alcohol increases the overall risk of dying from cancer.”

To read the full critique, click here.

These critiques are released with the permission of ISFAR.