Despite an extensive literature on the associations of alcohol consumption with brain structure and microstructure in individuals with AUD, there is limited research exploring these associations in individuals who consume alcohol but do not have AUD. In some studies of middle-aged and older adults, moderate alcohol consumption was associated with lower total cerebral volume28, gray matter atrophy29,30, and lower density of gray matter in frontal and parietal brain regions30. However, other studies have failed to show an association31, and one study showed a positive association of light-to-moderate alcohol consumption and GMV in older men32. One interpretation of these findings is that an inverse U-shaped, dose-dependent association exists between alcohol consumption and brain structure32. However, this interpretation was not supported by a longitudinal cohort study, which showed no difference in structural brain measures between individuals who did not consume alcohol and those who consumed between 1 and <7 alcohol units per week (i.e., light alcohol consumption), while individuals who consumed moderate-to-high amounts of alcohol (i.e., 14 or more alcohol units per week) showed GMV atrophy in the hippocampi and altered WM microstructure (lower FA, higher MD) in the corpus callosum33.
