The association between liver fibrosis markers and carotid atherosclerosis in non-alcoholic fatty liver disease is strongly influenced by age

Although an association between liver fibrosis and carotid atherosclerosis(CAS) in non-alcoholic fatty liver disease(NAFLD) is recognized, the influence of age on this relationship is unclear. This study aims to dissect this association and to determine the role of age therein. A total of 12,095 participants who underwent health check-ups were included in this study. They were categorized into CAS group (3,454 cases) and non-CAS group (8,641 cases). Multivariate logistic regression and propensity score matching (PSM) were employed to examine the associations of NAFLD and age with CAS. Furthermore, within the NAFLD subgroup, the relationships between liver fibrosis scoring models (NAFLD Fibrosis Score(NFS), Fibrosis-4(FIB-4), Aspartate Aminotransferase to Platelet Ratio Index(APRI), and CAS were assessed. The predictive performance of age and the liver fibrosis models for CAS was compared using receiver operating characteristic (ROC) curves and decision curve analysis (DCA). Additionally, restricted cubic spline (RCS) curves were applied to explore the potential non-linear relationship between age and CAS. In the overall population, both before and after PSM, multivariate logistic regression consistently demonstrated that older age (OR = 1.292, 95% CI: 1.227–1.360) and the presence of NAFLD (OR = 1.182, 95% CI: 1.034–1.351) were significantly associated with a higher prevalence of CAS (P < 0.05). Further analysis within the NAFLD subgroup confirmed that older age, higher NFS, and higher FIB-4 score were also positively correlated with CAS (P < 0.05). Both ROC and DCA curves consistently indicated that age had superior predictive performance for CAS compared to each of the liver fibrosis indices. In both sexes, RCS analysis revealed a non-linear relationship between age and CAS, characterized by an initial plateau followed by a sharp increase (P for non-linear < 0.001). In male individuals with NAFLD, hypertension, diabetes, and LDL-C demonstrated significant positive associations with CAS prevalence (P < 0.05). Among female individuals, only LDL-C showed a statistically significant association with CAS (P < 0.05). Both older age and NAFLD were independent positive correlates of CAS. Among individuals with NAFLD, age exhibited a significant positive correlation with the prevalence of CAS. The sharp rise in CAS prevalence underscores the necessity for early management of dyslipidemia, hypertension, and diabetes in middle-aged and elderly patients with NAFLD.