Objective: To assess associations between nonalcoholic fatty liver disease (NAFLD) and measures of brain health in a population-based sample of adults. Methods: Participants from the CARDIA study (Y25 exam; age 43-55 years) with concurrent computed tomography quantification of liver fat, visceral adipose tissue (VAT), and brain magnetic resonance (MR) images were included (n = 505). NAFLD was identified after exclusion of other causes of liver fat. Total tissue volume (TTV) and gray matter cerebral blood flow (GM-CBF) were estimated using 3T brain MR images. Results: NAFLD prevalence was 18%. NAFLD was associated with lower TTV and GM-CBF after adjusting for intracranial volume, demographics, and health behaviors (P < 0.04 for all). In models with additional adjustment for cardiovascular risk factors, the association of NAFLD with GM-CBF remained significant (P = 0.04) but was attenuated after adjustment for VAT (P = 0.06) and eliminated with BMI (P = 0.20). NAFLD was not associated with TTV after adjustment for cardiovascular risk factors (P = 0.10) or additional adjustment for VAT (P = 0.14) or BMI (P = 0.05). Conclusions: NAFLD is negatively associated with early brain health as assessed by MR measures of structure (TTV) and perfusion (GM-CBF). BMI and VAT attenuated this relationship, providing insight into the potential metabolic role of liver fat in brain health and disease.
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The authors thank the participants of the CARDIA study for their long-term commitment and important contributions to the study. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.