No one believes getting so drunk you pass out doesn’t have serious health consequences. However, a new
Researchers analyzed dementia diagnosis of over 130,000 people in Europe who had reported their drinking habits 14 years earlier. They found that those who reported losing consciousness after drinking had double the risk of dementia.
The risk was the same even if they were otherwise moderate drinkers, which is about a pint of beer or glass of wine per day.
According to the
Scientists examined seven European cohort studies from the U.K., France, Sweden, and Finland to include 131,415 people.
The participants, aged between 18 and 77 years, weren’t diagnosed with dementia during the years when they reported their alcohol consumption (1986 to 2012).
At follow-up, an average of 14 years later, they were examined for symptoms of dementia.
Over 96,000 people in this group reported passing out due to alcohol. Of these, over 10,000 reported having lost consciousness from drinking in the past year.
“Binge drinking tends to be most problematic among college aged youth and young adults,” Dr. Scott Krakower, unit chief of psychiatry at Zucker Hillside Hospital, Glen Oaks, New York, told Healthline.
The moderate drinkers who hadn’t passed out while drinking were used as the reference group. Compared with other participants, those who reported alcohol-induced loss of consciousness were more likely to drink hard liquor and beer, rather than wine.
After excluding participants with early or late onset Alzheimer’s, and cardiovascular conditions to find risk of cognitive impairment, the study authors concluded, “The findings of this study suggest that alcohol-induced loss of consciousness, irrespective of overall alcohol consumption, is associated with a subsequent increase in the risk of dementia.”
“It is felt that alcohol-induced blackouts are related to the effects of alcohol on the hippocampus,” said Dr. Kevin Conner, neurologist at Texas Health Arlington Memorial Hospital and Texas Health Physicians Group. “The hippocampus is the primary area of the brain that affects memory formation, storage, and retrieval.”
Conner explained that alcohol impairs an important part of the brain called
“This ultimately affects the retrieval of memory,” he said, adding that, “Additional brain injury can occur secondary to brain injuries related to falls, seizures, or asphyxiation from vomit, which may cause oxygen deprivation.”
According to Conner, the brain may heal from alcohol-induced damage, “depending on the extent and duration of alcohol exposure.”
He explained that some memories may be recalled from a blackout if they’re “stimulated by outside influences, such as a smell, video, or auditory events that may trigger other pathways of memory.”
But he warned that there are long-term, irreversible effects of long-term alcohol exposure.
These include Wernicke-Korsakoff syndrome, “where there can be eye movement changes, balance difficulties, and confusion that may progress to full psychosis and dementia.”
Conner emphasized that irreversible brain shrinkage (atrophy) as well as nerve damage (peripheral neuropathy), are also related to long-term alcohol exposure. Also, “Liver failure can affect the brain, leading to somnolence, confusion, liver flap [tremors], coma, and death.”
According to the
Moderate drinking is
A 2018 study
“The long-term effects of moderate alcohol consumption defined as 14 drinks per week maximum, or two drinks max per day, have been shown to perhaps reduce the risk of dementia,” agreed Conner.
He pointed out that other studies have shown abstaining to have little to no effect, however: “Across almost all studies, though, higher levels of consumption have been shown to be detrimental to brain and cardiovascular health.”
New research finds that even moderate drinkers can double their risk of dementia, if they drink themselves unconscious — even rarely.
Experts say that alcohol impairs important parts of brain function, and while some alcohol-induced damage can heal, there is a significant risk of permanent injury.
The relationship between alcohol and health is complicated, with research also showing both abstaining from alcohol and excessive drinking in middle age may increase dementia risk.