Liver Cancer Risk Factors: How Lifestyle Plays a Role

Liver cancer is a serious and sometimes life-threatening disease. While liver cancer risk is influenced by your liver condition, genetics and viral infections, your lifestyle also plays a major role. Liver cancer risk factors include alcohol consumption, smoking habits, weight, diet and level of physical activity.

Heavy alcohol use has been associated with increased liver cancer risk. When alcohol is consumed and broken down in the body, certain compounds, such as acetaldehyde (a carcinogen), are produced. These compounds can directly damage liver cell DNA, potentially leading to liver cancer and other cancers. Some of these compounds are also associated with liver cirrhosis, which increases the risk of liver cancer.

Alcohol may also make it easier for other dietary or environmental cancer-causing compounds, such as those in tobacco smoke, to enter cells and damage DNA. Alcohol can also disrupt cell cycles and increase chronic inflammation, which can also lead to liver cancer.

Ethanol is classified by the International Agency for Research on Cancer (IARC) as a Group 1 carcinogen. This implies that there is sufficient evidence associating alcohol consumption with cancer in humans. The amount of alcohol consumed is positively correlated with the risk of developing cancer and all alcohol use comes with some level of risk.

Heavy or excessive drinking has been defined by the US Dietary Guidelines as:

• 4 or more drinks on any day or 8 or more per week for women
• 5 or more drinks on any day or 15 or more per week for men

In the US, a “standard drink” contains 14 grams, or about 0.6 fluid ounces, of “pure” ethanol. For example, a standard drink in the US is equivalent to a 12 fl oz can of beer.

Recent studies have shown that for every 12 grams of alcohol consumed daily (e.g., about the amount in a beer can), the risk of developing hepatocellular carcinoma (HCC) increases by approximately 11.5%. The risk of developing cirrhosis also increases by about 6.2% with the same consumption. Furthermore, heavy alcohol consumption (more than 3 drinks a day) is associated with an approximately 2-fold increased risk of two types of liver cancer, HCC and intrahepatic cholangiocarcinoma. This risk is further increased in those who have cirrhosis.

Even for those without cirrhosis, heavy drinking can also increase liver cancer risk. Heavy alcohol users with hepatitis B (HBV) or C (HCV) are also linked to increased liver cancer risk as compared to those with HBV or HCV infection who drink only moderate or zero amounts of alcohol.

It is well known that smoking increases the risk of lung cancer. However, did you know that it can also increase the risk of liver cancer?

Smoking may directly or indirectly increase liver cancer risk. Tobacco smoke contains many chemical compounds that are carcinogenic, such as tar and vinyl chloride. These carcinogens may directly lead to undesired effects on tumor-suppressing genes, which can in turn lead to tumor development. Indirectly, smoking products contain toxic substances that may eventually exacerbate the effects of alcohol on the liver, therefore accelerating cirrhosis.

The effects of smoking tobacco on liver cancer risk vary according to different factors, such as:

• Number of cigarettes smoked per day: Risk increases with the number
• Number of years the person has smoked: Risk increases with the number of years
• Whether a smoker has an active HBV or HCV infection: Risk increases in the presence of infection
• Whether a smoker regularly consumes large amounts of alcohol: Risk increases with consumption of alcohol as compared to those who neither smoke nor drink

“I’ve already been smoking for a few years. Will quitting now make any difference?”

It may be comforting and encouraging to know that people who have smoked but stopped have a lower risk than those who still smoke. They still have a higher risk than those who have never smoked, but this may also depend on the length of time since they stopped smoking. In a large study from the US (the Liver Cancer Pooling Project), it was found that individuals who quit smoking more than thirty years ago had an equivalent risk to those who never smoked.

Obesity promotes liver cancer through mechanisms such as lipotoxicity, insulin resistance and chronic inflammation. This results in damage to liver cells and DNA, which can lead to the development of liver cancer. Being overweight or obese can also lead to diabetes, metabolic dysfunction-associated steatotic liver disease (MASLD) and cirrhosis, which increases the risk of developing liver cancer.

Studies have shown that compared to individuals with normal weight, those who were overweight or obese had a 17% and 89% increased risk of liver cancer, respectively.

What you eat on a regular basis may also affect your chances of developing liver cancer. Some foods associated with liver cancer risk include:

• Red/processed meat such as pork, beef, ham and bacon
• High-fat dairy products and butter, but not low-fat dairy
• Foods with high amounts of added sugar: Consumption of sugar increases the risk of HCC by 43% per 50g/day of total sugar
• Soft drinks: Consumption of more than 6 servings (cans) / week was associated with 80% increased HCC risk vs. non-consumers, adjusting for total energy intake, alcohol consumption, BMI, physical activity, level of educational attainment, and diabetes status
• Artificially-sweetened soft drinks: Artificially-sweetened soft drinks increased HCC risk by 6% per 1 serving increment

In contrast, some foods and dietary components that are related to a reduced liver cancer risk include:

• White meat such as fish and poultry
• Vegetable fats such as grape seed oil and cocoa butter
• Dietary fiber: Consumption of dietary fiber reduces HCC risk by 30% per 10g/day of total dietary fiber
• Coffee: It has been suggested in some studies that coffee may have a protective effect from HCC. Coffee drinkers, compared to non-coffee drinkers, were shown in studies to have a reduction in HCC risk

High levels of physical activity may be associated with a decrease in liver cancer risk. In a prospective study covering 1.4 million participants, researchers found that high levels of physical activity were linked to a decrease in 13 types of cancer, including liver cancer.

It is recommended that adults have at least 150 to 300 minutes of moderate-intensity physical activity per week. A pooled analysis of US and European cohorts showed that physical activity lowers the risk of HCC by 45%. Notably, even brisk walking alone for more than 2.5 hours a week reduces the risk of developing HCC by 50%.

While some liver cancer risk factors, such as genetics, are generally unavoidable, lifestyle factors can be controlled to some extent. By maintaining a healthy weight and diet, minimizing or avoiding consumption of alcohol and smoking tobacco, you can minimize your liver cancer risk. Additionally, preemptive methods such as getting hepatitis B vaccinations and going for liver cancer screenings when appropriate also support maintaining liver health and overall well-being.