What is alcohol-use disorder? Chronic drinking now linked to early-onset dementia

Numerous studies have indicated that excessive alcohol consumption can cause neurological problems over time. Now, a new study claims to have found another worrying link between the bottle and the brain.

The Lancet Public Health journal published a report on 20 February in which researchers have managed to trace a connection between chronic drinking and dementia. The team used data from the French National Hospital Discharge of over one million patients diagnosed with the cognitive disability between 2008 and 2013.

The study discovered that nearly 16.5% of all males and 4% of all females in the group were also diagnosed with alcohol-use disorders.

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

Of particular interest was the connection between alcohol abuse and early-onset dementia which starts developing before the age of 65. Of the test group, 57% of the 57,000 patients diagnosed with early-onset dementia had chronic heavy drinking problems where in they would consume more than four drinks a day.

"The findings indicate that heavy drinking and alcohol use disorders are the most important risk factors for dementia, and especially important for those types of dementia which start before age 65, and which lead to premature deaths," Dr Jürgen Rehm, the study's co-author and director of the CAMH Institute for Mental Health Policy Research, said.

"What is most surprising about this paper is that it has taken us so long to recognise that alcohol misuse and dependence are such potent risk factors for the development of dementia," Robert Howard, professor of old age psychiatry at University College London told The Guardian.

Schwarzinger said the information collected showed that once the brain was affected by alcohol consumption, there was no way of repairing the damage. "It is very striking that for people who were heavy drinkers and had at least a period of abstinence, the level of risk of dementia is about the same," he pointed out.

A 2012 Health and Retirement Study conducted by the Peninsula College of Medicine and Dentistry (PCMD) and the University of Exeter came to similar conclusions. It revealed that people who engaged in binge drinking had a 62% higher chance of suffering from decline in cognitive function.

According to the research, which was conducted on around 5,000 participants above the age of 64, from 2002 to 2010, men and women who went on binge sessions at least twice a month were at higher risk of dementia.

"That's a real worry because there's a proven link between cognitive decline and risk of dementia. Those who reported binge drinking at least twice a month were more than twice as likely to have higher levels of decline in both cognitive function and memory," Dr Iain Lang of Peninsula College of Medicine and Dentistry, said at the time.

What is alcohol use disorder?

According to the US National Institute of Alcohol Abuse and Alcoholism, alcohol use disorder or AUD is the term used to describe a chronic relapsing brain disease characterised by compulsive alcohol use, loss of control over alcohol intake, and a negative emotional state when not using.

Most people suffering from AUD will engage in binge drinking — with men consuming five or more drinks within two hours; and women having at least four drinks within the same period.

As per NIAAA, one standard drink can be defined as:

12 ounces (355ml) of regular beer (about 5% alcohol). 1 pint glass can hold between 473ml-568ml beer.

8 to 9 ounces (237 to 266ml) of malt liquor (about 7% alcohol)

5 ounces (148ml) of unfortified wine (about 12% alcohol)

1.5 ounces (44ml) of 80-proof hard liquor (about 40% alcohol)