Moderate Alcohol Consumption Linked to Pathological Changes in Brain

Jun 12, 2017 by News Staff / Source

A new study led by University of Oxford researchers has found that alcohol consumption, even at moderate levels, is associated with increased risk of adverse brain outcomes including hippocampal atrophy — a form of brain damage that affects memory and spatial navigation. The study was published online in the journal BMJ on June 6, 2017.

              Even moderate drinking is linked to pathological changes in the brain. Image credit: Howerla.

“Alcohol use is widespread and increasing across the developed world. It has historically been viewed as harmless in moderation, defined variably from 9-18 units (72-144 g) a week,” said lead author Dr. Anya Topiwala, a clinical lecturer in psychiatry at the University of Oxford, and co-authors.
“While chronic dependent drinking is associated with Korsakoff syndrome and alcoholic dementia, the long term effects of non-dependent alcohol consumption on the brain are poorly understood.”
“Light-to-moderate drinking has been associated with a lower risk of dementia and a reduced incidence of myocardial infarction and stroke. Brain imaging studies, however, have thus far failed to provide a convincing neural correlate that could underpin any protective effect.”
          So Dr. Topiwala and colleagues set out to investigate whether moderate alcohol consumption has a beneficial or harmful association — or no association at all — with brain structure and function.
The researchers used data on weekly alcohol intake and cognitive performance measured repeatedly over 30 years for 550 healthy men and women (mean age 43 at study baseline) who were taking part in the Whitehall II cohort study.
Brain function tests were carried out at regular intervals and at the end of the study, participants underwent an MRI brain scan.
Several factors that could have influenced the results (known as confounding) were taken into account, such as age, sex, education, social class, physical and social activity, smoking, stroke risk and medical history.
After adjusting for these confounders, the authors found that higher alcohol consumption over the 30 year study period was associated with increased risk of hippocampal atrophy.
While those consuming over 30 units a week were at the highest risk compared with abstainers, even those drinking moderately (14-21 units per week) were 3 times more likely to have hippocampal atrophy compared with abstainers.
          There was no protective effect of light drinking (up to 7 units per week) over abstinence.
Higher consumption was also associated with poorer white matter integrity and faster decline in language fluency. But no association was found with semantic fluency or word recall.
“This is an observational study, so no firm conclusions can be drawn about cause and effect; some limitations could have introduced bias,” the scientists said.
“However, key strengths include the information on long term alcohol consumption and the detailed available data on confounding factors.”
“As such, our findings have important potential public health implications for a large sector of the population.”
“The findings support the recent reduction in UK safe limits and call into question the current US guidelines, which suggest that up to 24.5 units a week is safe for men, as we found increased odds of hippocampal atrophy at just 14-21 units a week, and we found no support for a protective effect of light consumption on brain structure,” they said.
“Alcohol might represent a modifiable risk factor for cognitive impairment, and primary prevention interventions targeted to later life could be too late.”