Trending Clinical Topic: Alcohol

Ryan Syrek


April 01, 2022

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Little more than a month after the World Heart Federation issued a policy brief that declared no amount of alcohol can be considered safe for the heart, new studies addressing alcohol's effect on the brain, cancer risk, and amyotrophic lateral sclerosis (ALS) incidence resulted in this week's top trending clinical topic. A new study out of the United Kingdom suggests that even a single drink per day is linked to detectable changes in the brain (see Infographic).

Researchers examined functional MRI brain scans from 36,678 healthy adults aged 40-69 years and compared findings with participants' weekly alcohol consumption, adjusting for confounders (eg, age, sex, height, socioeconomic status, country of residence). The study found negative relationships between alcohol intake and global gray- and white-matter measures, regional gray-matter volume, and white-matter microstructure indices. These associations were widespread across the brain, and the magnitude increased with the average absolute number of daily alcohol units consumed by participants.

Beyond the brain, a recent study determined that heavy drinking during early adulthood may raise the risk for cancer in adulthood, even if drinking stops or decreases in middle age. A study out of Australia included 22,756 women and 15,701 men. Heavy drinking was set at an average alcohol intake of at least 60 g/d, equivalent to six standard drinks. During 485,525 person-years of follow-up among women, 2303 incident alcohol-related cancers were diagnosed, most commonly breast (64%) and colorectal cancer (31%). During 303,218 person-years of follow-up among men, 789 alcohol-related cancers were found, most commonly colorectal cancer (83%).

Researchers identified three distinct lifetime alcohol intake trajectories for women: lifetime abstainer (39%), stable light (54%), and increasing moderate (7%). Six trajectories were identified for men: lifetime abstainer (14.3%), stable light (51.5%), stable moderate (20.4%), increasing heavy (6.6%), early-decreasing heavy (5.1%), and late-decreasing heavy (2.2%). For men, the strongest associations with alcohol-related cancer were for the early-decreasing-heavy trajectory (hazard ratio [HR], 1.75) and the late-decreasing-heavy trajectory (HR, 1.94), with the increasing-heavy trajectory not far behind (HR, 1.45). For women, compared with lifetime abstention, the alcohol intake trajectory classified as increasing moderate (30-59 g/d) was associated with a greater risk for alcohol-related cancer overall (HR, 1.25).

Despite the significant and overwhelming evidence that alcohol increases cancer risk, most Americans remain unaware. An analysis of the 2020 Health Information National Trends Survey 5, Cycle 4, included 3865 adults, approximately half of whom were nondrinkers; it found that only about one third (31.8%) were aware that alcohol increases cancer risk. Numbers were even lower for individual beverage type: 20.3% for wine and 24.9% for beer. Still, more than half supported adding both health warning labels (65.1%) and information on recommended drinking guidelines (63.9%) to alcoholic beverage containers.

Alcohol was also recently found to be one of the factors in the development of ALS. In addition to body mass index (BMI), high-density lipoprotein (HDL) cholesterol, and white blood cell proportions, alcohol intake was found to possibly play a causal role in ALS, a genome-wide DNA methylation study suggests. Analyzing blood samples from 6763 patients and 2943 controls, researchers identified 45 DNA methylation sites related to ALS in 42 genes that are enriched for pathways and traits related to metabolism, cholesterol biosynthesis, and immunity. DNA methylation patterns were then tested as proxies for ALS risk factors. HDL cholesterol, BMI, white blood cell proportions, and alcohol intake were found to be independently associated with ALS.

The dangers of alcohol have arguably never loomed larger, especially in the United States. The number of Americans who died from alcohol-related causes increased dramatically during the first year of the pandemic, according to a new study . Deaths rose above 99,000 in 2020, a 25% increase from the nearly 79,000 deaths documented in 2019. The average annual increase was 3.6% between 1999 and 2019. Each new study confirming or suggesting a new negative health association with alcohol seemingly garners attention. The latest batch certainly did, making alcohol this week's top trending clinical topic.

Learn more about alcohol toxicity.


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