Vitamin D, systemic inflammation, and motoric cognitive risk: exploring the risk factors and mediation pathways

Introduction Motoric cognitive risk (MCR) syndrome, defined by subjective cognitive complaints and slow gait, is a predementia condition associated with multiple adverse outcomes. Although vitamin D deficiency and systemic inflammation have been implicated in cognitive and motor decline, their interaction in the context of MCR remains unclear. Methods This cross-sectional study included 312 hospitalized adults aged ≥60 years. Serum 25(OH)D levels, systemic immune-inflammation index (SII), and standardized clinical assessments were obtained within 48 h of admission. Multivariable regression and mediation analyses were performed to evaluate associations and underlying pathways. Results The prevalence of MCR was 17.9%. Older age, greater comorbidity burden, poor sleep quality, lower 25(OH)D levels, and higher SII were independently associated with MCR. Mediation analysis showed that systemic inflammation accounted for approximately one-quarter of the association between lower 25(OH)D and higher MCR risk, with the strongest indirect effect observed at 25(OH)D ≤ 20 ng/mL. Discussion Vitamin D deficiency and systemic inflammation are important determinants of MCR. The identified vitamin D–inflammation pathway may contribute to motoric cognitive vulnerability and provide insights for early risk stratification and preventive strategies in geriatric populations.