In the study they say that 27% of the variance is explained by age. So the effect of alcohol consumption certainly is insignificant compared to the effect of age.

However, the authors think the effect of alcohol is notable because that 0.8% was still larger than any other factor they tested, like smoking.

> Alcohol consumption was linearly and negatively associated with indices of brain health across most of the brain.

> Detrimental effects of drinking appear to be greater than other modifiable factors. Current ‘low risk’ drinking guidelines should be revisited to take account of brain effects.

The authors are pretty clear. You are, of course, free to draw your own conclusions.

No, it was found to have a statistically significant influence on grey matter volume.