A new study by investigators from Mass General Brigham suggests that heavy alcohol use may lead to more severe brain bleeds and cause long-term brain vessel damage at a younger age. The team’s results, based on patients treated for brain bleeds at Massachusetts General Hospital, are published online in Neurology, the medical journal of the American Academy of Neurology.

“The brain bleed is one of the most lethal and disabling conditions known to human beings,” said corresponding author Edip Gurol, a clinician investigator in the Mass General Brigham Department of Neurology and associate professor of neurology at Harvard Medical School. “They come on suddenly, cause severe damage, and often leave patients with life-changing disabilities. It’s one of the most difficult conditions to recover from.”

A brain bleed — also called an intracerebral hemorrhage or hemorrhagic stroke — happens when a blood vessel inside the brain bursts. Up to 50 percent of people with this condition die, and 30 percent are severely disabled. Only 20 percent of people who sustain a brain bleed can take care of themselves independently a full year later, Gurol said.

The study used a cohort of 1,600 patients admitted between 2003 and 2019 to Massachusetts General Hospital who had a brain bleed that was not a result of an injury or trauma. They used CT scans to assess the size and location of the brain bleed. They checked MRI scans for signs of damage to the brain’s small blood vessels.

About 7 percent of the brain-bleed patients reported consuming three or more drinks a day. Compared with those who didn’t drink, the people who drank heavily were younger when the brain bleed happened (average age 64 versus 75) and had bleeds that were about 70 percent bigger. They were twice as likely to have a bleed deep inside the brain or one that spread into the brain’s fluid-filled spaces. The researchers saw that an even lower level of alcohol intake, two drinks per day, was significantly associated with younger age of onset of a brain bleed.

The researchers hypothesize that heavy alcohol use raises blood pressure, damaging the small blood vessels in the brain, making them weak and more likely to leak or burst.

People who drank heavily had lower platelet counts (cell fragments that help blood clot) and higher blood pressure when they arrived at the hospital. They were more likely to show evidence of damage in the tiny blood vessels in the brain, which is linked to dementia, memory loss, and walking problems. It’s also a major risk factor for a brain bleed.

The researchers hypothesize that heavy alcohol use raises blood pressure, damaging the small blood vessels in the brain, making them weak and more likely to leak or burst. On top of that, lowered platelet counts make it harder for the body to stop bleeding. Together, these factors greatly increase the risk of a brain bleed.

Drinking less is a key part of stroke and brain health prevention efforts, the researchers said.

“We now know that heavy drinking leads to larger, earlier brain bleeds,” said Gurol. “Minimizing or stopping alcohol use is an important step to lower that risk. Even for people at relatively low brain-bleeding risk, limiting alcohol consumption to no more than three drinks per week may be an effective measure to protect against all types of stroke and to preserve both brain and cardiovascular health.”

This study has some limitations. Alcohol use was self-reported, the number of people who drank heavily was small, it took place at a single hospital, and the cohort investigated was mostly white patients. It also captured only one point in time, so it cannot show cause and effect. Future research with larger, more diverse groups should explore how different levels of alcohol use affect small vessel disease, brain aging, and the risk of blockage-type strokes.

This study was funded by National Institutes of Health.