Chronic heavy drinking major risk factor for dementia: The Lancet

21 Feb 2018 --- Excessive alcohol use is a major risk factor for onset of all types of dementia, especially early-onset dementia, according to a French nationwide observational study, published in The Lancet Public Health journal. Previous research has shown mixed results regarding the effect of alcohol on cognitive health, with some studies showing a possible benefit of light to moderate drinking, while others have found detrimental effects of heavy drinking on dementia risk.

The study included over one million adults diagnosed with dementia between 2008 and 2013. Of the 57000 cases of early-onset dementia (before the age of 65), the majority were either alcohol-related by definition (39 percent) or had an additional diagnosis of alcohol use disorders (18 percent).

According to the World Health Organisation (WHO) definitions, consuming more than 60g of pure alcohol a day for men (around 6 or more standard drinks per day on average) and more than 40g per day for women (around 4 or more standard drinks per day) can be considered chronic heavy drinking.

This study looked specifically at the effect of alcohol use disorders, and included people who had been diagnosed with mental and behavioral 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 to reduce the alcohol-attributable burden of dementia.

“The link between dementia and alcohol use disorders needs further research, but is likely a result of alcohol leading to permanent structural and functional brain damage. Alcohol use disorders also increase the risk of high blood pressure, diabetes, stroke, atrial fibrillation, and heart failure, which may, in turn, increase the risk of vascular dementia. Lastly, heavy drinking is associated with tobacco smoking, depression, and low educational attainment, which are also risk factors for dementia,” says lead author Dr. Michaël Schwarzinger, Translational Health Economics Network, France.

“Our findings suggest that the burden of dementia attributable to alcohol use disorders is much larger than previously thought, suggesting that heavy drinking should be recognized as a major risk factor for all types of dementia. A variety of measures are needed, such as reducing availability, increasing taxation, and banning advertising and marketing of alcohol, alongside early detection and treatment of alcohol use disorders,” says Dr. Schwarzinger.

There are some limitations to the study, including that there is a risk of individual medical details being misclassified or missing due to the administrative recording of data. In addition, due to stigma, it is likely that alcohol use disorders are underreported and only the most severe cases included as they involved hospitalizations, which could mean that the association is underestimated.