Occasional heavy drinking poses major risk to liver health

People may assume that if they drink lightly during the week or month, heavy drinking on the occasional Friday or Saturday may not cause their liver harm. 

New research suggests otherwise, according to a Keck Medicine of USC study published today in Clinical Gastroenterology and Hepatology. 

Researchers discovered that people with metabolic dysfunction–associated steatotic liver disease (MASLD), the most common liver condition in the country affecting one-in-three adults, face significantly higher risk of liver fibrosis, or harmful scarring of the liver, if they engage in episodic heavy drinking. Episodic heavy drinking is four or more drinks in one day for women and five or more drinks in one day for men, at least once a month. 

Those who consume large amounts of alcohol in a single day at least once per month are three times more likely to develop advanced liver fibrosis than individuals who spread out the same total alcohol intake over time, according to the findings. 

Younger adults and men were more likely to report episodic heavy drinking, and the more drinks consumed at one time, the more liver fibrosis people tended to have. 

This study is a huge wake-up call because traditionally, physicians have tended to look at the total amount of alcohol consumed, not how it is consumed, when determining the risk to the liver. Our research suggests that the public needs to be much more aware of the danger of occasional heavy drinking and should avoid it even if they drink moderately the rest of the time." 

Brian P. Lee, MD, MAS, hepatologist and liver transplant specialist with Keck Medicine and principal investigator of the study

How the study was conducted 

Lee and his colleagues used data from the nationally representative National Health and Nutrition Examination Survey, a long-running health survey of the United States population. They included data from more than 8,000 adults, collected between 2017 and 2023. In particular, they looked at the link between episodic heavy drinking and advanced liver fibrosis to understand how drinking patterns - not just total drinks - may cause harm even to moderate drinkers, which is considered seven drinks a week for women and 14 or less for men. 

The research team focused on MASLD because of its prevalence among Americans. MASLD affects people with excess weight, obesity or other metabolic conditions, such as Type 2 diabetes, high blood pressure or high cholesterol, and is on the rise. Additionally, while MASLD is not defined as alcohol-related, Lee and his colleagues wanted to explore if alcohol did in fact play some role in the condition. 

More than one-half of the adults included in the study reported episodic heavy drinking and almost 16% of patients with MASLD were episodic heavy drinkers. 

The researchers compared people with MASLD with the same age, sex and average weekly alcohol consumption, segmenting some as episodic heavy drinkers and others as non-episodic heavy drinkers, to reach their conclusion that episodic heavy drinkers with MASLD had nearly three times higher odds of experiencing advanced liver fibrosis.

Lee speculates that episodic heavy drinking can harm the liver both directly and indirectly. Drinking large amounts of alcohol at once can overwhelm the liver and increase inflammation, which leads to scarring and damage. People with MASLD may be particularly at risk, as Lee's previous research has shown that obesity, high blood pressure and other conditions associated with MASLD can more than double liver disease risk. 

Alcohol-related liver disease has more than doubled in the last two decades, according to Lee. He believes this trend is driven by pandemic-era surges in drinking and an increase in people with risk factors for MASLD, like obesity and diabetes. 

"Although this study focused on patients with MASLD, these findings may also be pertinent to a broader patient population," said Lee. "With more than half of adults reporting some episodic heavy drinking, this issue deserves further attention from both physicians and researchers to help better understand, prevent and treat liver disease."