Alcohol is the biggest avoidable risk factor for dementia, according to research.
The conclusions come from over 1 million people diagnosed with dementia in France.
The damage done by alcohol was particularly striking for early-onset dementia: that which occurs before 65-years-old.
Of the 57,000 cases of early-onset dementia in the sample, 57% were related to chronic heavy drinking.
Heavy drinkers are defined as those consuming an average of 4-5 standard US drinks per day for a man, or 3 standard US drinks for a woman.
This is like drinking close to a bottle of wine per day for a man or over half a bottle per day for a woman.
While this study only looked at heavy drinking, others have suggested moderate alcohol intake also carries risk for the brain.
Dr Jürgen Rehm, study co-author, said:
“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.
Alcohol-induced brain damage and dementia are preventable, and known-effective preventive and policy measures can make a dent into premature dementia deaths.”
Alcohol use disorders are thought to shorten life by an average of 20 years.
The link between heavy drinking and alcohol may be even stronger than this study reveals as only the most severe cases were included in this study.
Dr Bruce Pollock, study co-author, said:
“As a geriatric psychiatrist, I frequently see the effects of alcohol use disorder on dementia, when unfortunately alcohol treatment interventions may be too late to improve cognition.
Screening for and reduction of problem drinking, and treatment for alcohol use disorders need to start much earlier in primary care.”
The study was published in the journal The Lancet Public Health (Schwarzinger et al., 2018).