Abstract
Low-level alcohol consumption at or below current guidelines (≤1 standard drink equivalent/day for females, ≤2 standard drink equivalents/day for males) has been proposed to carry minimal systemic health risks. The neurobiological correlates of low-level drinking in healthy adults are not well characterized. To date, no study has concurrently assessed the associations of low-level alcohol consumption, modeled as a continuous rather than categorical variable, with regional brain perfusion (blood flow) and morphometrics in healthy, non-smoking adults. This study examined the associations between alcohol consumption and magnetic resonance measures of regional brain perfusion (n = 27) and cortical volumes and thickness (n = 45) in healthy non-smoking adults (22-70 years of age) with no history of alcohol use disorder. All participants consumed ≤60 standard drink equivalents/month over the 1 year preceding study. Average number of drinks/month over lifetime was 21 ± 11. We hypothesized that a greater multiplicative product of age and total lifetime drinks consumed predicts lower regional brain perfusion, volumes, and thickness. Greater age by total lifetime drinks were related to lower perfusion in numerous bilateral regions, primarily in the frontal, parietal, and occipital lobes, as well as lower bilateral average cortical perfusion. Greater age by total lifetime drinks were related to thinner cortex, primarily in the bilateral frontal and parietal lobes, as well as lower bilateral average cortical thickness. Findings indicate alcohol consumption considered "low risk" may have consequences for the integrity of cortical tissue, particularly with advancing age. These results may have implications for current harm reduction strategies and alcohol consumption public health guidelines.