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A new study suggests that moderate to heavy alcohol use may be linked to a higher risk of stroke in young adults. Mats Silvan/EyeEm/Getty Images
  • In a new study, researchers analyzed the relationship between alcohol consumption and stroke risk among young adults in Korea.
  • The findings show that moderate and heavy alcohol use is linked to a higher risk of stroke.
  • Researchers and some health experts recommend that young adults reduce their alcohol consumption to reduce their risk.

Stroke is the second leading cause of death worldwide and accounts for around 11% of deaths each year, according to the World Health Organization (WHO).

What’s more, the World Stroke Organization (WSO) estimates that stroke incidence increased by 70% between 1990 and 2019, and deaths from stroke increased by 43% in the period.

Stroke survivors experience physical disabilities and cognitive impairments that often limit their economic activities for the rest of their lives.

While stroke mostly impacts those over 44 years old, increasing numbers of younger adults are experiencing stroke. The WSO estimated that around 8% of the 13.7 million strokes each year occur in adults under 44 years of age.

But more than 90% of stroke cases are linked to modifiable risk factors such as alcohol consumption, which has been increasing globally. For instance, alcohol consumption increased by 104% per capita in East Asia between 1990 and 2017. Research from 2019 shows that global alcohol consumption is projected to increase substantially.

While heavy alcohol consumption is linked to stroke risk, little is known about the effects of moderate drinking on stroke risk over time.

In a new study, researchers investigated the effects of cumulative alcohol consumption on adults ages 20 to 39 years old in South Korea.

They found that young adults who engaged in moderate to heavy drinking were at a higher risk of stroke.

The study was recently published in Neurology.

For the study, the researchers examined national health record data from 1,536,668 men and women.

Participants ranged in age from 20 to 39 years old and underwent four annual health examinations between 2009 and 2012. Stroke risk was the primary health outcome among subjects.

The researchers split alcohol consumption into four categories measured by alcohol consumption in grams per week:

  • none
  • mild drinking: 0-105 g
  • moderate drinking: 105-210 g
  • heavy drinking: over 210 g

For reference, 105 grams of alcohol is equivalent to 7 and a half 12-ounce beers or one-and-a-half standard bottles of wine.

Additionally, researchers examined subjects’ age, sex, and income, alongside comorbidities such as hypertension, diabetes, and cancer.

Participants were followed for an average of 5.6 years. During the follow-up period, 3,153 people experienced a stroke.

After analyzing the data, the researchers noted that stroke incidence steadily increased alongside cumulative alcohol consumption.

Subjects with 2 years of moderate to heavy drinking were at a 19% higher risk of stroke. Meanwhile, those with 3 years had a 22% increased risk, and those with 4 years had a 23% higher risk.

Researchers also found that heavy drinkers had a 28% higher stroke risk than non-drinkers, although the risk for mild to moderate drinkers was not statistically significant.

The researchers concluded that reducing alcohol consumption should be emphasized for young adults with heavy drinking as a stroke prevention strategy.

Dr. John Mendelson, a board certified internist and chief medical officer of Ria Health, not involved in the study, noted to MNT:

“Stroke is exceedingly uncommon in young people, and hemorrhagic strokes are even rarer. Hemorrhagic strokes usually occur in people during spikes of extremely high blood pressure or in patients on anticoagulants.”

“In this study, the increased risk of stroke was likely due to elevated blood pressure, possibly during alcohol withdrawal. It is also possible that head trauma contributed to the increased risk of stroke — heavy drinkers are more likely to fall and [experience] head injuries.”

– Dr. John Mendelson, board certified internist

To understand how drinking is linked to stroke risk, Medical News Today spoke with Tamar Rodney, Ph.D., RN, assistant professor at the Johns Hopkins School of Nursing, who was not involved in the study.

“Alcohol affects multiple body organs primarily because it is carried throughout the body via [the] blood,” Dr. Rodney said.

“The way the body processes alcohol means that it will affect multiple organs very quickly, which includes the brain.”

“Repeated occurrences of alcohol to the brain can trigger events that lead to lack of oxygenated blood flow or clots in the brain, which can cause a stroke. The brain, however, is just one of many organs that can dysfunction [due to] excessive alcohol intake.”

– Tamar Rodney, Ph.D., RN, assistant professor of nursing

Debbie Fetter, Ph.D., assistant professor of teaching nutrition at the University of California, Davis, not involved in the study, told MNT:

“Alcohol is an example of an empty calorie source. [It] provides almost no nutritional value [and is] just an energy source at 7 kcals [per] gram. [It] has also been recognized as a carcinogen since 1988 — ethanol in alcohol is classified as a group 1 carcinogen.”

“Although people consume alcohol for a variety of reasons, from a health viewpoint, it’s recommended to the public to limit or refrain,” Dr. Fetter added.

Dr. Fetter noted that high alcohol intake and binge drinking are linked to increased risks of cardiovascular-related health outcomes, including:

“Alcohol intake increases the risk of irregular heartbeat, in particular atrial fibrillation, which can cause clots to develop in the heart and be dislodged to other organs, including the brain,” Dr. Sandra Narayanan, board certified vascular neurologist and neurointerventional surgeon at Pacific Stroke & Neurovascular Center at Pacific Neuroscience Institute in Santa Monica, CA, not involved in the study, told MNT.

“This is an important and potentially preventable risk factor for ischemic stroke — [when blood supply to a part of the brain is interrupted or reduced],” she added.

The researchers acknowledged that their findings have limitations.

They noted that as their study population was Korean, their findings may not apply to other ethnicities. They also recognize their results might be subject to recall bias due to the use of self-report questionnaires for alcohol consumption.

In addition, researchers further noted they did not assess the difference between mild drinking and abstinence.

Dr. Fetter noted that as the study was observational in nature, it does not prove a causative link between alcohol consumption and stroke risk.

“The type of alcohol wasn’t reported [or] individually analyzed (i.e., beer vs. wine vs. spirits, etc.),” she said.

“Some drinks can come with additional factors that can influence health, such as added sugars in a mixed cocktail.”

Dr. Siddharth Kharkar, a board certified neurologist in Nanavati Hospital, Mumbai, India, not involved in the study, added that the impact of smoking was not properly assessed.

He said it remains unclear whether a young person who is a heavy drinker but a light smoker could be at high risk for a stroke, but noted a possible implication.

“A key finding of this study is that the increase in stroke [risk] was mostly for the ‘hemorrhagic’ variety of stroke,” Dr. Kharkar said.

Excessive consumption of alcohol is associated with high blood pressure. This partly — but not completely —explains the increased risk of hemorrhagic stroke in these young people.”

The 2020–2025 U.S. Dietary Guidelines for Americans recommends either abstaining from alcohol or limiting consumption to moderate intake.

Drinking in moderation is considered 2 drinks or less per day for males and 1 drink or less per day for females, according to the dietary guidelines.

“This is based on theoretical considerations for differences in body composition,” Dr. Fetter explained.

“Generally, males may have greater lean body mass [or] water compared to females—but this isn’t always the case. It seems that for most people consuming alcohol at low levels can have minimal impact on health, but many people who consume alcohol tend to exceed current recommendations.”

– Debbie Fetter, Ph.D., assistant professor of teaching nutrition

To that end, the 2020 Dietary Guideline Advisory Committee recommended reducing the current alcohol recommendations to less than 1 drink per day regardless of biological sex.

But the advisory committee’s recommendation wasn’t included in the current dietary guidelines due to what scientists considered to be insubstantial evidence.

Whether or not moderate drinking is linked to increased stroke risk may depend on factors such as an individual’s age, sex, and weight — and if they are living with certain health conditions.

If you’re wondering whether your drinking habits could raise your stroke risk, it’s a good idea to speak with your doctor.

When asked whether the current alcohol recommendations are sufficient to prevent an increased stroke risk, Dr. Mendelson said:

“The authors found a dose response for alcohol and stroke. There was no increase in stroke risk at what are considered healthy drinking levels, so the current recommended drinking levels remain valid and appropriate.”

But Dr. Rodney disagreed and said the current alcohol recommendations were insufficient to prevent an increased stroke risk. She said that more needs to be done to address the underlying reasons why young adults engage in moderate to heavy drinking.

Dr. Rodney further noted that approaches to limit alcohol consumption should resemble warnings against smoking.

“The message regarding the long-term dangers of alcohol consumption can be supported by research findings like this. From a health perspective, an equally-robust message about the dangers of moderate and heavy drinking and the long-term impact should be a part of health education and a national message. A larger focus on increasing educational strategies on the potential negative outcomes — like stroke — would be a great start.”

– Tamar Rodney, Ph.D., RN, assistant professor of nursing