Alcohol Consumption and Dementia Risk

A recent study indicates that any level of alcohol consumption may raise the risk of developing dementia as people age, which contradicts earlier research findings.

Some past studies suggested that light drinking—defined as fewer than seven drinks weekly—might offer more protection than abstaining entirely from alcohol. However, those studies mainly focused on older populations and did not distinguish between those who used to drink and lifelong nondrinkers, potentially influencing the outcomes, according to the researchers.

The new research, published in the journal BMJ Evidence-Based Medicine, explored how specific genes related to alcohol could affect its impact on the brain.

“The genetic analysis revealed that even small amounts of alcohol could increase the risk of dementia,” explained Anya Topiwala, the lead author and a senior clinical researcher at the University of Oxford in the UK.

This study is notably large, and combining observational data with genetic analysis proved crucial, Topiwala noted in an email.

The methodological approach, known as Mendelian randomization, minimizes the risk of extraneous factors clouding the connection between alcohol and dementia, according to Topiwala. This method also reduces concerns about whether dementia might be influencing alcohol consumption rather than the other way around, and it evaluates the lifetime impact of drinking.

In contrast, observational studies typically provide a limited view of drinking behaviors later in life, relying on individuals’ memories, which can be unreliable.

Dr. Richard Isaacson, a neurologist and director of research at the Institute for Neurodegenerative Diseases in Florida, remarked that while this study offers some evidence of alcohol’s detrimental effects on brain health, it isn’t conclusive. He emphasized that for individuals with the APOE4 gene, which heightens Alzheimer’s risk, avoiding alcohol seems wise based on current findings.

Isaacson pointed out that for those with a lower genetic predisposition to Alzheimer’s, the effects of drinking could vary significantly based on factors like timing and quantity. For instance, having two drinks on an empty stomach just before bed may be worse for the brain than a single drink a few times a week with dinner.

An Emerging Link Between Alcohol and Dementia

The investigation analyzed data from nearly 560,000 participants in the UK Biobank, which includes individuals from England, Scotland, and Wales, as well as data from the US Million Veteran Program, representing diverse ancestral backgrounds.

In the observational segment, participants self-reported their alcohol consumption, which researchers then correlated with their dementia risk over time.

“Individuals who reported small alcohol consumption (under 7 drinks per week) had lower dementia risk compared to heavy drinkers (over 40 drinks per week),” remarked Tara Spires-Jones, a professor of neurodegeneration at the University of Edinburgh.

Interestingly, non-drinkers and those who claimed never to drink had similar dementia risks to heavy drinkers in this part of the study, according to Spires-Jones, who is also affiliated with the UK Dementia Research Institute.

The researchers also analyzed genetic data from 45 different dementia studies involving 2.4 million individuals, comparing genetic markers linked to lifetime alcohol use.

A higher genetic risk correlated with an increased likelihood of dementia, exhibiting a direct relationship between alcohol consumption and dementia risk. Topiwala noted that the risk of dementia increased by 15% for individuals consuming three drinks weekly versus just one.

Moreover, double the genetic predisposition for alcohol dependency was associated with a 16% rise in dementia risk, the study indicated.

While neither part of the study can definitively conclude that alcohol consumption directly causes dementia, Spires-Jones emphasized that it adds to a growing body of evidence linking alcohol intake to a higher dementia risk. Additionally, foundational neuroscience research has demonstrated that alcohol can be harmful to brain neurons.