Association of Liver Fibrosis with Cognitive Test Performance and Brain Volume Changes in the UK Biobank Study

Abstract Background Liver fibrosis is a chronic liver condition that, though frequently subclinical, has widespread systemic effects. We hypothesized that liver fibrosis is associated with worse cognitive performance and corresponding brain imaging changes. Method We examined the association of liver fibrosis with cognition and brain volumes among adults in the UK Biobank study, which prospectively enrolled approximately 500,000 people starting in 2007 and subsequently collected cognitive test and brain MRI data for some participants. We included participants with available liver fibrosis, cognitive test, and brain imaging data. Liver fibrosis was defined at baseline using validated cutoffs of the Fibrosis‐4 (FIB‐4) liver fibrosis score. The primary cognitive test outcome was the Digit Symbol Substitution Test (DSST), a multidomain test. Secondary cognitive test outcomes were executive function tests (Trails A, Trails B, Reaction Time) and memory tests (Numeric Memory, Pairs Matching). The primary imaging outcome was white matter hyperintensity volume; secondary outcomes were hippocampal volume and total brain volume. We used multiple linear regression models to evaluate the association of liver fibrosis with cognitive test performance and brain volumes while adjusting for potential confounders. Results Among 105,313 participants with cognitive test data, the mean age was 56.1 years and 56% were women. Standard liver chemistries were largely in the normal range. However, 2.0% (95% CI, 1.9‐2.1%) had liver fibrosis based on FIB‐4 scores. Cognitive tests were completed a median of 5.8 years after baseline liver fibrosis assessment. After adjusting for demographics, socioeconomics, education, body mass index, metabolic syndrome, hypertension, diabetes, dyslipidemia, and tobacco and alcohol use, liver fibrosis was associated with worse performance on the DSST (β = ‐0.40; 95% CI, ‐0.60, ‐0.20; P<0.001) (Figure). Liver fibrosis was associated with worse executive function but not memory test performance (Table). We included 34,730 participants with brain MRI, obtained a median of 9.3 years after baseline. In adjusted models, liver fibrosis was associated with lower hippocampal volume (β = ‐58.8; 95% CI, ‐94.7, ‐22.9; P = 0.001) and higher white matter hyperintensity volumes (β = 1142.8; 95% CI, 311.6, 1973.9; P = 0.007) (Table, Figure). Conclusion Liver fibrosis is associated with worse cognitive performance, perhaps explained by hippocampal volume loss and white matter hyperintensity burden.