A new study, published in The Lancet Public Health, investigates the association between chronic heavy drinking and dementia.
Prof Matt Field, Professor of Addiction, University of Liverpool, UK Centre for Tobacco and Alcohol Studies (UKCTAS), said:
“This important study of French hospital records demonstrates a clear link between alcohol use disorder and dementia, particularly early-onset dementia. Both early onset dementia and alcohol use disorder are fairly uncommon, but this study showed that the two were closely related: more than 57% of people with early-onset dementia also had a history of alcohol use disorder. This association remained robust even when statistically adjusting for other things that are associated with heavy drinking and dementia, such as tobacco smoking, hypertension, and obesity.
“Further work is required to tease apart the contributions of different components of alcohol consumption (for example, the frequency of drinking occasions versus the volume consumed), to increased risk of early-onset dementia.
“At first glance, these findings might appear inconsistent with other reports, including some that made the news very recently, that low to moderate drinking is associated with better ‘cognitive health’. These findings can be reconciled because there is a big difference between low to moderate drinking, and alcohol use disorder. However, both types of research are subject to the usual limitations of observational studies: they cannot definitely establish cause and effect, and any observed relationships are almost certainly confounded by other factors, not all of which can be easily measured.”
Dr David Llewellyn, Senior Research Fellow in Clinical Epidemiology, University of Exeter Medical School, said:
“This enormous study provides thought provoking new data suggesting that alcohol use disorders are strongly associated with dementia risk. Reducing heavy drinking may not reduce dementia risk or delay its onset however, as it was not a randomised trial demonstrating causality and other factors may explain the link.”
Prof Robert Howard, Professor of Old Age Psychiatry, UCL, 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. We have long known that alcohol is directly neurotoxic, thiamine deficiency in alcoholics devastates memory, alcohol-related conditions such as cirrhosis and epilepsy can damage the brain and that vascular brain damage is accelerated by alcohol. Surprisingly, we’ve not traditionally considered alcohol and its misuse as an important risk factor for dementia and we were clearly wrong not to have done so.
“The study showed that alcohol misuse within a large French population-based sample led to a tripling of the risk of developing dementia in people under the age of 65. This has huge public health implications for the prevention of dementia, for which we have no current cures or significant treatments. Of course, most cases of Alzheimer’s disease, the most important cause of dementia, arise after the age of 65 with an incidence that rises exponentially with increasing age. It would be important to establish whether the effect demonstrated in this paper also applies to such later onset dementia cases, where any preventative intervention could have an even greater effect.”
Prof Tara Spires-Jones, UK Dementia Research Institute Programme Lead, and Deputy Director of the Centre for Discovery Brain Sciences, University of Edinburgh, said:
“This very large study found an association between heavy drinking and dementia risk. The results strongly support the conclusion that drinking enough alcohol to cause behavioural disorders or chronic-alcohol-related diseases (such as liver disorders) likely increases your risk of developing dementia. This finding is not too surprising since it is well known that excessive alcohol use can cause alcohol-related dementia. There are other studies that indicate that moderate amounts of red wine as part of a healthy diet may protect against developing dementia, however it is crystal clear that alcohol abuse is bad for your brain.”
Dr Doug Brown, Chief Policy and Research Officer at Alzheimer’s Society, said:
“We’ve known for a while that heavy drinking can increase your risk of developing dementia. This study suggests that alcohol abuse disorders may be responsible for more cases of early-onset dementia than previously thought.
“But because this study only looked at hospital admissions, and was based in France, we would need further research in other healthcare settings and countries to fully understand how many cases of early-onset dementia are caused by alcohol abuse.
“This study in no way suggests that moderate alcohol intake could cause early-onset dementia. The study doesn’t change the advice to stick to no more than 14 units of alcohol a week. Anyone concerned about heavy drinking should visit their GP to discuss ways of cutting down and the support on offer.”
Dr Sara Imarisio, Head of Research at Alzheimer’s Research UK, said:
“This well-conducted study looked at the medical records of thousands of people and highlighted a strong association between harmful drinking and dementia risk. This is not the first time research has revealed a link between alcohol misuse and dementia, and the findings lend even more weight to calls for people to drink within recommended guidelines.
“As this study only looked at the people who had been admitted to hospital due to chronic heavy drinking, it doesn’t reveal the full extent of the link between alcohol use and dementia risk. Previous research has indicated that even moderate drinking may have a negative impact on brain health and people shouldn’t be under the impression that only drinking to the point of hospitalisation carries a risk.
“Taking steps to curb the amount of alcohol you consume can have far-reaching health benefits and isn’t limited to improving brain health. Although there is no sure-fire way to completely prevent dementia, the best current evidence indicates that as well as only drinking in moderation, staying physically and mentally active, eating a healthy balanced diet, not smoking, and keeping weight, cholesterol and blood pressure in check are all good ways to support a healthy brain as we age.”
* ‘Contribution of alcohol use disorders to the burden of dementia in France 2008–13: a nationwide retrospective cohort study’ by Michaël Schwarzinger et al. published in The Lancet Public Health on Tuesday 20 February 2018.
Prof Matt Field: “None to declare.”
Dr Sara Imarisio: “No conflicts of interest to declare.”
None others received.