Association Between Non-alcoholic Fatty Liver Disease and Subclinical Atherosclerosis Assessed by Carotid Intima-Media Thickness: A Systematic Review and Meta-Analysis.

Non-alcoholic fatty liver disease (NAFLD) is variably associated with subclinical atherosclerosis, measured using carotid intima-media thickness (CIMT), although findings across studies remain inconsistent. This systematic review and meta-analysis aimed to evaluate the association between NAFLD and subclinical atherosclerosis, assessed by CIMT, and to explore possible sources of heterogeneity. A literature search covering almost 25 years (January 2000 to March 2026) was conducted. Included studies reported CIMT measurements in adults diagnosed with NAFLD using either liver biopsy or ultrasonography. A random-effects model was used to calculate pooled effect sizes using Hedges' g. Subgroup analyses were performed based on geographic region (Asia vs Europe) and diagnostic modality for NAFLD. Eight studies comprising 4,384 patients with NAFLD and 2,843 controls were included. The pooled effect size showed a significant increase in CIMT among patients with NAFLD (Hedges' g = 0.79; 95% CI: 0.42 to 1.17). Considerable heterogeneity was observed (I² = 94.13%). Studies using ultrasonography demonstrated a smaller effect size (Hedges' g = 0.66; p = 0.001) compared with those using liver biopsy (Hedges' g = 1.36). A borderline significant difference was observed between European populations (Hedges' g = 1.12) and Asian populations (Hedges' g = 0.64; p = 0.090). Publication bias was detected; however, after adjustment using the trim-and-fill method, the association remained significant (adjusted Hedges' g = 0.62; 95% CI: 0.36 to 0.88). Overall, NAFLD was significantly associated with increased CIMT, suggesting a higher burden of subclinical atherosclerosis in affected individuals. Future studies should employ standardized diagnostic criteria and uniform measurement protocols to reduce heterogeneity.