Non-alcoholic fatty liver disease, liver fibrosis score and cognitive function in middle-aged adults: The Framingham Study

Background Non-alcoholic fatty liver disease (NAFLD) is common and has been recently related to brain health. We aimed to assess the relationships of NAFLD and its severity, using the NAFLD fibrosis score (NFS), with cognitive performance. Methods Framingham study Offspring and 3rd generation participants were included if they attended exams 9 (2002-2008) and 2 (2008-2011), respectively, were free of dementia and stroke, and did not have excessive alcohol intake. Between 2008 and 2011, participants underwent Multi-detector computed tomography scans of the abdomen to determine NAFLD diagnosis and the NFS was used to categorize the severity of fibrosis. Cross-sectional relationships of NAFLD and the NFS with cognitive testing of memory, abstract reasoning, visual perception, attention and executive function were assessed, while adjusting for multiple cardiometabolic variables including visceral adipose tissue, diabetes and insulin resistance. Results Of the 1287 participants (mean age = 61 +/- 12 years, 48% men), 378 (29%) had NAFLD. The presence of NAFLD was not associated with cognitive function. However, among those with NAFLD (mean age = 61 +/- 12 years; 58% men), high compared to low risk of advanced fibrosis was associated with poorer performance on similarities (beta = -2.22 +/- 0.83; P = 0.009) and trail-making B minus A (beta = -0.11 +/- 0.05; P = 0.028), independently of potential confounders. Conclusions Participants with high risk of advanced fibrosis may have poorer cognitive function compared to those with low risk, particularly in executive function and abstract reasoning. Future findings are necessary to evaluate the value of the NFS as a biomarker that predicts cognitive impairment and dementia and to explore the role of hepatic fibrosis in brain health.