How Alcohol Affects Your Risk of Lung Cancer

The link between lung cancer and alcohol consumption has long been considered controversial. There remains contention as to the true impact of alcohol on lung cancer, with some studies arguing that the link is at best uncertain and others suggesting that alcohol may have a protective effect in certain cases.

But research published in 2020 strongly suggests that alcoholism is indeed an independent risk factor of lung cancer—most especially squamous cell lung carcinoma. The study suggests that the same genetic variations that can predispose a person to alcohol abuse may increase a person’s risk of lung cancer as well.

This major study adds lung cancer to the growing list of other cancers thought to be linked to alcohol.

Alcohol and Cancers

Alcohol has now been classified as a carcinogen (cancer-causing agent) by the U.S. Department of Health and Human Services and a Group 1 carcinogen by the International Agency for Research on Cancer.

Unlike some carcinogens, such as tobacco smoke, alcohol is thought to promote the growth of an existing cancer rather than initiate the onset of cancer. These include malignancies such as liver cancer, colon cancer, rectal cancer, breast cancer, and head and neck cancers.

Generally speaking, the risk of cancer is directly linked to the amount of alcohol consumed. However, research published in the June 2018 edition of PLOS ONE suggests that the risk is not linear.

Scientists found that light to moderate alcohol consumption (defined as one to three drinks per week) was associated with a lower risk of all cancers compared to never drinking or drinking infrequently (less than one drink per week).

Early Findings for Lung Cancer

Although some cancers have a clearer association with alcohol use, studies investigating alcohol’s link to lung cancer have been largely mixed. One of the first studies able to draw a clear association reviewed the medical histories of 126,293 people from 1978 to 2008 and concluded that heavy drinking was associated with a 30% increased risk of lung cancer.

The study, published in the October 2011 edition of Chest, could find no association between light to moderate drinking and lung cancer, supporting earlier research. But it also noted that the variations in risk could not be explained away by the amount or type of alcohol consumed.

Smoking, not surprisingly, played a more central role in a person’s risk of lung cancer, particularly among heavy drinkers who are more likely to be smokers. But, the study also revealed that the risk of lung cancer was increased in former smokers or never-smokers, suggesting that other factors (such as genetics or lifestyle) may play a part.

Alcoholism, Lung Cancer, and Genetics

Lung cancer is a complex disease brought on by a multitude of intersecting risk factors, including genetics, environment, and lifestyle. As such, it is difficult to determine how much alcohol contributes to the risk of lung cancer that other factors—most predominately smoking—can contribute more directly and measurably.

In the aforementioned 2020 study, researchers with the University of Liverpool decided to look at the genetic factors associated with alcoholism and found a surprisingly link to the rate of lung cancer in 171,216 adults in the United Kingdom.

Alcoholism, also known as alcohol use disorder (AUD), is considered to be strongly influenced by a person's genetics. Among the genetic variations that influence AUD are the genes alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). These genes direct how alcohol is metabolized, while indirectly influencing the reward pathways in the brain.

For people with alcohol use disorder, these genetic variations can increase the speed by which alcohol is broken down and excreted by the body while increasing the amount of the "feel-good" hormone dopamine in the brain. These factors can predispose an individual to AUD.

When looking closer at the genetic variations, the researchers found four (ADH1B, GCKR, SLC39A8, and KLB) that had a strong association with AUD in the general population. These same variants were causally linked to lung cancer, most significantly squamous cell lung cancer (the second most common type of lung cancer affecting the airways).

Risk in Never-Smokers

These findings support an earlier study in which alcohol use was inversely associated with lung cancer in never-smokers (meaning that people who drank more had a lower risk and those who drank more had a higher risk).

The study, published in the May 2017 edition of the International Journal of Cancer, looked specifically at the impact of alcohol use in over 2,500 never-smokers with lung cancer and 9,000 never-smokers without lung cancer.

The researchers found that people who drank lightly or moderately had a 20% lower risk of lung cancer than occasional drinkers or non-drinkers. (The risk of lung cancer in heavy drinkers was not explored in this study.) Non-small cell lung cancers, like squamous cell carcinoma and lung adenocarcinoma, were most commonly seen in the study population. Small cell lung cancers were not.

Not all researchers agree with the findings. A 2018 study in the European Journal of Public Health not only reported that never-smoking women who drink have as much as a four-fold increased risk of lung adenocarcinoma but concluded that wine poses the greatest risk. There was no increase in the risk among men and no correlation between the amount of alcohol a woman drank and her risk of lung cancer.

As compelling as the findings were, they were limited by the relatively small size of the study (1,301 women and men).

Alcohol and Lung Cancer Survival

Research also suggests that alcohol use can influence morbidity and mortality (illness and death) in people with lung cancer. Contributing to this phenomenon is a person's perception of wellness following cancer treatment.

According to a review of studies from the Mayo Clinic College of Medicine, as many as 69% of people with lung cancer were drinkers prior to their diagnosis. Of these, roughly 16% quit alcohol following cancer treatment. Those who didn't were nine times more likely to describe themselves as being in poor health compared to those who did.

A 2018 study in the Journal Thoracic Disease further reported that around one in eight people requiring lung cancer surgery have AUD.

On the other hand, the study found that the identification and treatment of AUD prior to lung cancer surgery may not only improve outcomes but reduce the risk of alcohol withdrawal symptoms by 75%.

A Word From Verywell

As contradictory as some of these findings are, they all raise valid concerns about the potential links between alcohol and lung cancer. This is especially true in men and women who smoke, who are 23 and 13 times more likely, respectively, to develop lung cancer than non-smokers. Alcohol only adds to the risk.

Moreover, the risk is not only limited to people with alcoholism. Despite the fact that light to moderate drinking appears to have a preventive effect in some studies, this should not suggest that a couple of glasses of alcohol per week "prevents" cancer.

With so many other factors contributing to the onset of lung cancer, it is far better to focus on maintaining optimal health—including a healthy diet, exercise, limited alcohol use, and the complete cessation of smoking—than any perceived benefits of alcohol use.