Three pints a day can lead to dementia
Three pints of beer or two large glasses of wine each day can push drinkers towards early dementia, a new study reveals today.
Scientists who looked at 57,000 cases of dementia diagnosed before the age of 65 found that 39pc could be attributed to alcohol-related brain damage.
The warning comes in a major observational study, which involved more than a million adults diagnosed with dementia between 2008-2013.
It concluded that heavy drinking may be a major risk factor for early-onset dementia.
The World Health Organisation defines chronic heavy drinking as consuming more than 60 grams of pure alcohol per day for men and 40 grams for women.
That equates to around six standard drinks for men - the equivalent of two or three pints of beer.
For women, the limit is even lower at around four standard units. A 100ml glass of wine holds one unit, but large glasses can hold 250ml, well over two units.
The findings are published in the 'Lancet Public Health' journal. Commenting on the French research, Professor Brian Lawlor, of the Global Brain Health Institute, in Trinity College Dublin, said: "This is a very important study as it highlights the negative impact of heavy alcohol use on brain health and the increased risk of developing dementia.
"While we need further studies on the effects of chronic alcohol use on brain health and cognitive function, there is now enough information available to indicate that alcohol use, particularly heavy use, is a potentially modifiable risk factor for dementia.
"The results of this study provide an important health message that we need to get across to the general public: if you are a heavy drinker, cutting back or cutting out alcohol is good for your brain health and may decrease your risk of developing dementia in the longer term," said Prof Lawlor, who is co-director of the institute and also a consultant in St James's Hospital.
Previous research showed mixed results regarding the effect of alcohol on brain health, with some studies showing a possible benefit of light to moderate drinking. Others have found detrimental effects of heavy drinking on dementia risk. This study looked specifically at the effect of alcohol use disorders, and included people who had been diagnosed with mental and behavioural disorders or chronic diseases that were attributable to chronic harmful use of alcohol.
As a result of the strong association found in this study, the authors suggest that screening, brief interventions for heavy drinking, and treatment for alcohol use disorders should be implemented.