(CNN) — Heavy drinking is associated with increased risk of a type of brain injury linked with memory and thinking problems.
That's according to a new study in which researchers defined heavy drinking as eight or more alcoholic drinks per week.
This study, which was published in the journal Neurology, comes when clinicians and public health advocates are raising awareness of alcohol use disorder and issues related to excessive alcohol consumption.
To help people think about their drinking habits, given the key takeaways of this report, I spoke with CNN wellness expert Dr. Leana Wen. Alcohol affects the brain, but how much alcohol is too much? How can people recognize signs of problem drinking in themselves and in their loved ones? Is it necessary to totally abstain, or are there ways to have a healthy relationship with alcohol?
Wen is an emergency physician and adjunct associate professor at George Washington University. She previously was Baltimore's health commissioner.
CNN: What does this new study show about alcohol and possible damage to the brain?
Dr. Leana Wen: This study involved a postmortem analysis of over 1,700 people who had an average age of 75 at the time of their death. Scientists examined their brain tissue to look for signs of brain injury, including a lesion called hyaline arteriolosclerosis, which is associated with memory and cognitive problems, and tau tangles, which are associated with Alzheimer's disease.
Separately, the researchers queried family members about participants' alcohol consumption. The participants were divided into four groups: those who never drank; those who had seven or fewer drinks weekly; those who had eight or more drinks a weekly, which was defined as heavy drinking; and former heavy drinkers who have stopped drinking.
Heavy drinkers had a whopping 133% higher likelihood of having hyaline arteriolosclerosis compared with nondrinkers, and that's after accounting for other factors that could affect brain health such as smoking. Former heavy drinkers had 89% higher odds of developing this lesion, and moderate drinkers had 60% higher odds.
Heavy drinkers also had a higher likelihood of developing tau tangles. Moreover, these participants were more likely to die an average of 13 years earlier compared with those who never drank.
I think these are compelling results that link heavy alcohol consumption with lasting impacts on the brain. It's especially telling that former heavy drinkers have evidence of sustained damage, although halting that heavy drinking does appear to lower risk.
There are caveats to this study. It is important to point out that these findings are associations that are suggestive, rather than proof of cause and effect. In addition, one limitation of the study is that it didn't measure duration of alcohol consumption or distinguish between those people who regularly consumed one or two drinks a night versus those who drank sporadically but heavily.
CNN: What is already known about how alcohol can affect the brain?
Wen: In the short term, alcohol use can disrupt the brain's communication pathways and make it harder for the brain to control thinking, coordination, balance, speech and judgment. High amounts of alcohol in a short time can lead to such significant impairment that key areas that control breathing and heart rate begin to shut down.
People with alcohol use disorder can have progressive brain changes that affect thinking and cognition. For example, a condition known as Wernicke-Korsakoff syndrome that is linked with severe alcohol use can be permanently disabling, with long-term memory loss. Smaller amounts of alcohol have been linked to premature aging and shrinking of the brain.
Given the plethora of studies demonstrating the effect of alcohol use on the brain, the findings from this new study aren't a surprise.
CNN: How much alcohol is considered too much?
Wen: Adults of legal drinking age should not drink more than one drink a day for women and two drinks a day for men, according to the US Dietary Guidelines for Americans
But these guidelines are controversial. Earlier this year, then-US Surgeon General Dr. Vivek H. Murthy issued guidance that alcohol consumption within the guideline amounts can be linked with elevated cancer risk.
Some people who are following these guidelines could be considered heavy drinkers, according to this new study. A man could consume, say, two drinks a day for five days a week and exceed eight drinks a week, which in this study is linked with signs of brain injury.
Another way to assess for excess alcohol consumption is whether there is binge drinking. Binge drinking is defined as four or more drinks on one occasion for women and five or more drinks on one occasion for men, according to the US Centers for Disease Control and Prevention. People who engage in binge drinking are at higher risk from injuries such as car accidents and falls. Moreover, the large amount of alcohol their bodies are exposed to is thought to cause more stress to their organs than if the drinks were metabolized over time.
CNN: Does drinking a lot result in addiction? How can people recognize signs of problem drinking in themselves or in their loved ones?
Wen: There are two separate but related issues. One is drinking levels of alcohol that exceed recommended amounts, whether over a weekly basis or heavily at once via binge drinking. Either type of excessive drinking can result in long-term problems, including impacts on the brain, heart and liver.
Another issue is physiological dependence from alcohol and problems stemming from a condition called alcohol use disorder. Alcohol Awareness Month is a time to raise awareness of this disorder, which is the most common substance use disorder in the United States. Nearly 29 million Americans age 12 and older meet criteria for diagnosis, which include loss of control over how much they drink, difficulty fulfilling work and caregiving responsibilities, and physical symptoms when they stop drinking such as nausea and sweating.
People can take several different self-questionnaires to screen for problem drinking. They also can look out for signs of alcohol use disorder in their loved ones. It's crucial everyone knows effective treatment exists for alcohol use disorder. No one should have to suffer alone.
CNN: Is it necessary to totally abstain, or are there ways to have a healthy relationship with alcohol?
Wen: This is an area that is hotly debated among clinicians and public health experts. The consensus is generally that less is better. Medical professionals are not going to tell someone who doesn't drink to start drinking. Moreover, the consensus is clear that excessive drinking is a problem. Binge drinking is associated with many risks, as is heavy alcohol use.
Where to draw the line on defining heavy alcohol use is not entirely clear. More and more research, including this study, are beginning to show that even alcohol usage within currently recommended guidelines could be associated with negative consequences.
At the same time, I think it's possible for people to have a healthy relationship with alcohol. One way to assess one's relationship with alcohol is with sobriety challenges such as Dry January and Sober October . These experiences can help people take stock of exactly how much they are drinking, how they feel when they abstain, and when and why they drink.
For instance, do they drink to mask negative feelings? Are they ashamed or feel loss of control by how much they drink? These are warning signs that people need to seek help from a mental health specialist or their primary care provider. Individuals who drink heavily also should be careful not to stop suddenly because the effects of sudden withdrawal can be dangerous. Those people who wish to cut back should do so under the care of their medical provider.
By Katia Hetter, CNN (CNN)