Moderate Alcohol Consumption and the Brain: Friend or Foe?

Thesis

Background

Alcohol consumption is widespread and increasing in some sectors of society. Whilst adverse effects on the brain of chronic heavy use are well characterised, the effects of more moderate use are poorly understood. Previous work has lacked prospectively gathered data on alcohol use. Robust evidence of harm would have important public health implications.

Methods

Associations between self-reported alcohol consumption data gathered over a thirty-year period (1985-2015), neuroimaging markers of brain structure and function, and cognition were examined in community dwelling older adults in the Whitehall II cohort (n=550). Structural, diffusion tensor, and resting state functional magnetic resonance imaging was performed in 2012 to 2015. Cognitive performance was determined cross-sectionally across multiple domains at the time of scanning and longitudinally throughout the study.

Results

No participants scored as alcohol dependent on the CAGE screening questionnaire. Higher alcohol consumption throughout the study was associated with hippocampal atrophy (even in those drinking 14-21 units (112-<168g) weekly), lower white matter integrity of the corpus callosum, increased functional connectivity within the Default Mode Network, and faster decline of lexical fluency. No protective effects of light drinking were found. Age, sex, premorbid IQ and white matter integrity predicted better verbal memory performance in the presence of small hippocampi.

Discussion

This thesis describes three novel neuroimaging associations with moderate alcohol consumption. Alcohol, even in small quantities, may represent a modifiable risk factor for adverse brain outcomes and faster cognitive decline. Learning effects or confounding by higher premorbid intelligence or social class may explain previous findings of a protective effect of moderate alcohol consumption.

Authors: Topiwala, A

• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford