News reports were reasonably accurate in their interpretation of the study. With measured headlines using words such as “may damage the brain” and “linked with”, these reported that the observational study found an association between moderate drinking and brain damage, not a causation.
The Financial Review ran the headline:
"The silent damage from drinking moderately down the decades"
and CBS News said:
"Even moderate drinking could harm the brain."
Others, such as the Deccan Chronicle, were more hyperbolic, hinting at causation:
"Moderate drinking leads to severe brain damage."
We know about 17% of Australians drink at levels considered to put them at risk of long-term harm such as diabetes, liver disease and cognitive problems.
And it’s well established heavy drinking over ten years or more can cause significant cognitive difficulties. These include disorders such as Korsakoff’s Syndrome and Wernicke’s Encephalopathy, where memory and other essential thinking functions, as well as motor coordination, are severely and permanently damaged.
But what about those of us who have two to three drinks a night?
First, this is an observational study that followed people over time, showing an association between their alcohol intake and certain cognitive functions. Observational studies cannot prove that one (alcohol) caused the other (impaired brain function).
And while alcohol can potentially affect multiple parts of the brain, the researchers found significant impact in only one part of the brain. And that did not appear to correlate with poorer brain functioning overall.