Story highlights

Research involved more than 1 million adult patients released from hospitals in France

Alcohol abuse was also associated with vascular risk factors, including high blood pressure

CNN  — 

Excessive alcohol use could increase your risk for all types of dementia, particularly early-onset dementia, according to a new study.

The study, published Tuesday in the journal Lancet Public Health, looked at over 1 million adults released from French hospitals between 2008 and 2013 who were diagnosed with dementia, a clinical syndrome characterized by a progressive deterioration in cognitive ability.

Using data from the French National Hospital Discharge database, the researchers found that alcohol-use disorders were diagnosed in 16.5% of the men with dementia and 4% of the women with dementia – over twice as much as in those without dementia for both sexes.

Alcohol-use disorders refer to “the chronic harmful use of alcohol or alcohol dependence,” the researchers wrote.

In order to isolate the role of alcohol use, patients with neurological disorders such as Parkinson’s and Huntington’s, which can also lead to dementia, were excluded from the study.

“The most novel result is the large contribution of alcohol-use disorders to the burden of dementia over the lifespan,” said Dr. Michael Schwarzinger, a researcher at the Transitional Health Economics Network in Paris and a leading author of the study.

The association was particularly strong for those with early-onset dementia, diagnosed when the patient is younger than 65. Over half of the individuals in the early-onset group had alcohol-related dementia or an additional diagnosis of alcohol-use disorder.

“Given the strength of the association, what is the most surprising to me is that alcohol-use disorders had received so little interest in dementia research and public health policies,” Schwarzinger said.

How alcohol might damage the brain

Although many studies have shown a strong association between excessive alcohol use and dementia, this study is unique in its findings about early-onset dementia, according to Dr. Kostas Lyketsos, a neuropsychiatry professor and director of the Johns Hopkins Memory and Alzheimer’s Treatment Center who was not involved in the study.

“That is rather unique,” Lyketsos said. “It does remind us that alcoholics have shorter life expectancies.”

The study was also among the largest of its kind. But, according to Lyketsos, the large size could leave the study open to selection bias.

“There’s a tradeoff between size and precision of the variables,” he said. “The more people you have, the less confidence you have in the elements that go into the diagnosis of dementia.

“I also want to point out that this was really a sample of hospitalized individuals. It’s very unusual for people with dementia, at least in the milder stages, to be hospitalized,” he added.

Research suggests multiple ways heavy alcohol use can lead to dementia. First, ethanol and its byproduct acetaldehyde are known to have a toxic effect on the brain that can lead to long-term structural and functional brain damage, Schwarzinger says.

Heavy alcohol use can also lead to a condition called hepatic encephalopathy, characterized by a loss in brain function due to increases of ammonia in the blood caused by liver damage.

“Heavy drinking is also strongly associated with vascular risk factors such as high blood pressure or diabetes mellitus as well as cardiovascular diseases,” Schwarzinger added.

“Lastly, heavy drinking clusters (in) people with less education, smoking habits, and/or depression. All of these factors were found to be independent risk factors for dementia onset.”