There is no safe amount of alcohol when it comes to dementia, study finds

Drinking any amount of alcohol increases your risk of dementia later in life, according to a new study which questions the results of previous research.

Some research has suggested that light consumption – like less than seven drinks per week – can be more neuroprotective than not at all alcohol. These studies, however, focused on the elderly and did not make the difference between old drinkers and non-luns for life, have potentially distorted the results, the study authors said.

In the new study, published Tuesday in the journal BMJ Evidence-Based Medicine, researchers have analyzed how certain alcohol-related genes could have an impact on the way alcohol consumption affects the brain.

“The results of genetic analyzes (have shown) that even small amounts of alcohol could increase the risk of dementia,” said the main study author, Anya Topiwala, a researcher in the main clinic in the Oxford University of Psychiatry in the United Kingdom.

“This is the biggest study on the subject, and the combination of observational and genetic analyzes has been essential,” said Topiwala by e-mail.

Genetic analysis, called Mendelian randomization, is less likely to introduce a confusing or “parasitic” variable to explain the alcohol dementia relationship, Topiwala said.

Mendelian randomization also reduces the risk of reverse causality, such as dementia processes influencing alcohol consumption rather than the reverse, and it can also estimate the cumulative impact of alcohol consumption throughout a person’s life, Topiwala said. Observation studies, however, tend to capture an instantaneous consumption habits from median consumption to late and depend on the subject’s recall, which may not be exact.

“This is a fairly complicated study that provides evidence, but not final evidence, that alcohol can harm the brain, whatever the amount consumed,” said neurologist Dr. Richard Isaacson, director of research at the Institute of Neurodegenerative Diseases in Florida. Isaacson, who conducts studies on cognitive improvement in people genetically at risk of Alzheimer’s disease, was not involved in the new study.

“In my clinic, we say to people with the APOE4 genetic variant, which is the most common genetic risk factor for Alzheimer’s disease, that zero alcohol consumption is better based on available evidence,” he said in an email.

However, for people with less genetic risk for Alzheimer’s disease, it often depends on “when” and “how” people drink, added Isaacson. For example, he said, two glasses before bed on an empty stomach several nights will have a more harmful effect on brain health compared to a drink several times a week with a dinner early.

An emerging link between alcohol and dementia

The new study examined the data of nearly 560,000 people who participated in British biobank, a longitudinal study which included participants from England, Scotland and Wales, and the veteran program of the American millions, or MVP, which includes people of European, African and Latin American origin.

In this observational part of the study, people provided self-assessment of the quantity they drank and the researchers compared alcohol consumption with their risk of developing dementia over time.

“In the self-assessment study, people who declared consuming small amounts of alcohol (less than 7 drinks per week) had a lower risk than large drinkers (more than 40 drinks per week),” said Tara Spires-Jones, professor of neurodegeneration and director of the Center for Discovery Brain Sciences at the University of Edinburgh, in a declaration.

“Interestingly, in this part of the study, non-droops and people who declared that they never drink had a similar risk of dementia for people who drank a lot,” Spires-Jones, who is also a group leader at the United Kingdom Research Institute in London. It was not involved in the study.

The study then examined genetics of 45 dementia studies in 2.4 million people and compared genetic markers associated with alcohol consumption during a lifetime.

A higher genetic risk was associated with an increased risk of dementia, with a linear increase in the risk of dementia, the higher alcohol consumption.

“There is a risk of dementia of 15% higher for 3 drinks per week, against 1 drink per week through life,” said Topiwala.

In addition, a doubling of the genetic risk of alcohol dependence was associated with a 16% increase in the risk of dementia, according to the study.

“None of the two parties of the study can prove in a conclusive manner that alcohol consumption directly causes dementia,” said Spires-Jones. “But this adds to a large quantity of similar data showing associations between alcoholic contribution and the increase in the risk of dementia, and fundamental work of neuroscience has shown that alcohol is directly toxic to neurons in the brain.”

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