Neutrophil‐to‐Albumin Ratio Mediates the Association Between Life's Crucial 9 and Sarcopenia: A Cross‐Sectional Study

Background: Emerging evidence links cardiovascular health, inflammation, and sarcopenia (SP), but the mediating mechanisms remain unclear. Life's Crucial 9 (LC9), a novel metric integrating mental health with cardiovascular risk factors, and neutrophil-to-albumin ratio (NPAR), a cost-effective inflammatory biomarker, may jointly influence SP risk. This investigation seeks to examine the connection between LC9 and sarcopenia, assessing whether NPAR acts as a mediator in this relationship. Methods: Multivariable logistic regression, smooth curve fitting, subgroup analysis, and other methods were employed to investigate the relationship between LC9 and the incidence of SP. Additionally, mediation analysis was conducted to examine the potential relationship between NPAR levels, LC9, and SP. Results: for non-linearity = 0.001). Subsequent threshold analysis identified a turning point at an LC9 score of 73.33; the risk of SP decreased gradually before this point, whereas a more pronounced and accelerated decline was observed once the score exceeded 73.33. Conclusion: LC9 inversely correlates with SP, partially mediated by NPAR-driven inflammation, suggesting anti-inflammatory interventions may mitigate SP risk.