Higher stroke risk linked to consuming certain amount of alcohol, study finds
The Highlights of the Study
The latest study from Harvard University outlines the connection between heavy drinking and irreversible brain damage. It was published on Neurology, and one of the main arguments states that those who consume three or more alcoholic drinks on a regular basis are at a heightened risk of suffering a stroke, and other serious brain complications.
Although the negative effects of alcohol on one's health has been common knowledge for a while, the Harvard study shows that heavy drinking also alters one's brain, increasing the risk of a stroke, and the heart. Alcohol impacts the brain at the cell level, and the more sobering part of this finding is that heavy drinking alters the brain aging processes, and functions on a fundamental level.
The Methods of Study
The Harvard study also analyzed the case studies of 1,600 patients aged 75 and over that had been hospitalized for intracerebral hemorrhage, a specific and deadly type of stroke caused by bleeding in the brain, and in the worst cases, the hemorrhage results in permanent damage, and disability.
Data from 1,600 participants revealed that around 7% of the sample reached the benchmark of heavy drinkers. Three or more drinks a day which include a 12-oz. beer, a 5-oz. glass of wine, or 1.5-oz. of a distilled spirit qualifies as heavy drinking, and only by using this definition could you find a reliable measurement for cross country comparisons.
Heavy drinking with brain bleeds is concerning and the average age of the heavy drinkers was 11 years younger than the average age of the non heavy drinkers with brain bleeds. Heavy drinkers experienced their first brain bleed and major life event at 64 and moderately drinking at 75. More than a decade lost is more than concerning.
Heavy drinkers with brain bleeds suffered more severe bleeding which was a 70% increase than brain bleeds in moderate drinkers. The increase of bleeding is a key indicator and clinically important which leads to more extensive brain damage and increasing the morbidity of the patient. 70% increase of a bleed places a patient with severely increased morbidity and longer recovery times.
One of the most significant findings was the injury to white matter. Heavy drinkers were three times more likely to have severe white matter injury compared to moderate drinkers. White matter is made up of neural pathways in the brain that help different areas of the brain communicate with each other. You can think of it as your brain’s internal communication system. When this tissue breaks down, it directly correlates to problems with cognition, memory, attention, and accelerated aging of the brain — effectively speeding up the clock on cognitive deterioration.
Brain Health Beyond Stroke
The researchers also looked beyond acute damage from the bleeding itself. The brain imaging studies showed a much higher number of signs of cerebral small vessel disease in the brains of the heavy drinkers compared to moderate drinkers. Cerebral small vessel disease involves damage to the small vessels of blood throughout the brain, and is typically associated with aging, hypertension, dementia, and Alzheimer's disease. Think of it like the delicate plumbing of the brain developing rust.
What makes this finding particularly important is that cerebral small vessel disease often develops silently over time—years—with no outwardly obvious symptoms, and is thus considered "the silent killer" by neurologists. By the time a patient has a major stroke, the brain has often sustained considerable damage that is completely undetected. Research suggests that heavy drinkers may indeed accelerate the process of silent damage and set the stage for health crises—often years before they appear.
Dr. M. Edip Gurol, lead researcher with the Harvard team, highlighted the significance of the findings point blank in a statement to the Disability Research journal. Heavy alcohol use appears to speed up the small vessel disease process—leading the brain to become more likely to sustain catastrophic strokes and [2] significantly complicate recovery. If heavy alcohol use were reduced, confirmed Gurol, “there are a number of ways that benefits will be rendered—not only with decreasing stroke incidence, but also potentially slowing the small vessel disease process preventing future strokes, cognitive decline, and long-term disability in the later decades of life.
"Cutting back on heavy drinking may not only result in a lower risk of bleeding stroke for a person, but might also dysfunction cerebral small vessel disease," said Gurol. "Which may reduce a person's risk of having another stroke, cognitive decline, and long-term disability." Given their vast experience with alcohol-related brain injury and their own research, this is a entitled statement.
Tujague, the principal scientist with the International Alliance for Responsible Drinking in Washington, D.C. reviewed the result and offered her comments. While she is not directly involved with any of the research at Harvard, she confirmed that the final results were in line with prior studies exploring the association between alcohol and heavy drinking and risk of stroke. These independent recommendations confirm those made by the research team at Harvard.
"Those findings line up with some previous epidemiological studies that showed an increased risk for hemorrhagic stroke with heavier drinking," Tujague said thoughtfully. She also mentioned that heavier drinking is strongly linked to high blood pressure, a major contribution to hemorrhagic strokes. This link implies that alcohol injures the brain in multiple ways, meaning that there is not just one pathway, but there are multiple simultaneous pathways working in concert to create a chain of injury.
Important Limitations to Consider
While the study offers important insights, the researchers acknowledge a number of limitations that should be acknowledged and taken into account when interpreting the study. These are not limitations of the research that invalidate the research, but rather honest accounts of what the research can and cannot tell us.
First, the current study employed a cross-sectional format. The researchers looked at data at a single time point, as opposed to tracking participants over many years. A cross-sectional study is helpful for identifying associations, but the researcher cannot determine that the heavy drinking caused the strokes. Other contributors might be responsible for the outcomes, or the severity of the strokes resulted in participants not being able to drink as freely. With research like this, the "chicken or egg" question is always present: Was it the drinking that caused the stroke or was it something else?
Second, alcohol consumption was self-reported. This means that participants will either underestimate or overestimate how much they actually drink (independently and with or without intent) based on gender, stigma associated with heavy drinking or embarrassment. This is particularly exacerbated when a person's memory is asked to retrieve drinking patterns long after the fact. The uncertainty in measurement can impact the reliability of the results.
Third, researchers no longer had any information on the long-term drinking patterns of the participants. They only had knowledge about the participant's drinking habits at the time of their hospitalization. Researchers did not know if participants had a long history of heavy drinking for months or years or if they recently increased their drinking. Heavy drinking for 30 years is a very different scenario than a person who has only been drinking heavily for the past 30 days but they wouldn't be able to determine the difference in the study.
Implications for your health
The findings out of Harvard University provide compelling evidence supporting a burgeoning literature suggesting heavy consumption of alcoholic beverages has serious risks to the health of the brain and specific risks to health and life. The connection between three or more drinks per day and significantly poorer outcomes with advance age including stroke, among multiple factors, is well documented and increasingly harder to dismiss.
The good news about this study is it also indicates opportunity for positive change. Knowing the risks associated with heavy alcohol use may be motivating for a positive lifestyle change! Cutting back alcohol, especially at higher levels of consumption, may help mitigate the brain from aging and lessen catastrophic health events later in life. It's never too late to implement lifestyle changes that are positive for your health!
If you're worried about how much you drink, a good first step is to go talk to a doctor. Medical professionals can assess individual risk factors, understand your unique health situation, and provide you with personalized guidance on what safe levels of alcohol consumption look like or evidence-based strategies to reduce intake. They are not judging you, they are simply looking to help you live a healthier life.
The Harvard based study published in Neurology via the American Academy of Neurology represents really an important stepping stone to understanding how our lifestyle behaviors actually clearly affect our brains and brain health, as well as life span. As new research emerges and provides us these important associations, the case for moderate alcohol drinking or not drinking at all becomes more and more viable. Remember, your brain is really the command center of everything you do, think, and feel. Therefore, protecting it is important.