Heavy drinkers may be more likely than other adults to develop dementia, especially in middle age, a French study suggests.
For the study, researchers examined data from 2008-2013 on more than 31 million French hospital patients, including more than 1 million who were diagnosed with dementia. About 5% of the dementia patients had so-called early onset dementia that started before age 65, and most of these cases were alcohol-related, the study found.
“Chronic heavy drinking was the most important modifiable risk factor for dementia onset in both genders and remained so after controlling for all known risk factors for dementia onset,” said lead study author Rd. Michael Schwarzinger, chief executive officer of Translational Health Economics Network and a researcher at INSERM–Universite Paris Diderot, Sorbonne Paris Cite in France.
Surprisingly, heavy drinkers who got sober didn’t have a lower dementia risk than their peers who remained problem drinkers,” said Schwarzinger.
He added, “This finding supports that chronic heavy drinking leads to irreversible brain damage,” Schwarzinger added.
While some previous research suggests that alcohol may lead to cognitive impairments including a risk of dementia, other studies have linked light or moderate alcohol use to a healthier brain, researchers note in the Lancet Public Health.
Globally, an estimated 3.3 million people a year die as a result of alcohol misuse, accounting for about 6% of all deaths, according to the World Health Organization (WHO).
During the study period, 945,512 people were diagnosed with alcohol use disorders. Most of these cases were alcohol dependency.
With early onset dementia cases, however, the connection to alcohol appeared stronger. About 39% of these cases were attributable to alcohol-related brain damage, and another 18% were tied to other alcohol use disorders.
Alcohol use disorders were associated with three times the risk of dementia and twice the risk of early onset cases, the study found. Excluding alcohol-related brain damage, alcohol use disorders were still associated with a two times greater risk of vascular and other dementias.
The study wasn’t a controlled experiment designed to prove whether or how drinking might cause dementia or cause cognitive problems to develop in middle age.
The findings add to the evidence that heavy drinking can lead to cognitive problems, said Clive Ballard co-author of an accompanying editorial and Dean of the medical school at the University of Exeter in the U.K.
“Seven drinks per day in men and five drinks per day in women are harmful to the brain,” Ballard said.