Associations between twelve composite inflammatory indices and sarcopenia in a health examination population: a cross-sectional study.

Background: Sarcopenia is strongly linked to chronic inflammation, yet most studies have focused on individual inflammatory markers. Moreover, associations between inflammatory status and sarcopenia have not been systematically compared in health examination populations. This study explored the relationships between composite inflammatory indices and sarcopenia in individuals undergoing routine health examinations. Methods: This retrospective cross-sectional study included 2617 participants from a health examination cohort. Composite inflammatory indices were derived from peripheral blood cell counts and standard biochemical parameters. Independent associations between each index and sarcopenia were examined using multivariable logistic regression. Subgroup analyses by sex and age were conducted, restricted cubic spline models assessed potential non-linear relationships, and receiver operating characteristic curves were used to compare discriminative performance. Results: Among 2,617 participants, sarcopenia prevalence was 5.5%. After adjustment for confounders, higher inflammatory status was associated with increased sarcopenia risk. The C-reactive protein-to-lymphocyte ratio (CLR) showed the strongest association (Q4 vs. Q1: OR = 4.31, 95% CI 2.35-7.90). Higher levels of the C-reactive protein-to-albumin ratio (CAR), systemic immune-inflammation index (SII), and platelet-to-lymphocyte ratio (PLR) were also significantly associated with higher sarcopenia risk. Associations were consistent across sex and age subgroups (all interaction Conclusion: Several composite inflammatory indices derived from routine laboratory data are associated with sarcopenia risk in health examination populations and may provide additional information for assessing inflammation-related sarcopenia risk.