Abstract
<jats:p>ObjectiveTo investigate the associations between visceral adiposity, dyslipidemia, muscle mass, and Metabolic Syndrome (MetS) in a middle-aged and elderly Chinese population, and to quantify the mediating roles of dyslipidemia and muscle mass.MethodIn this cross-sectional analysis of 2,074 participants from the 2015 CHARLS, visceral adiposity (VAI), dyslipidemia (NHDL), and muscle mass (ASM) were assessed. Associations were evaluated using logistic regression, threshold effect models, and causal mediation analysis, with adjustment for confounders. Sensitivity was analyzed via E-values.ResultParticipants with MetS exhibited significantly higher VAI (7.24 vs. 3.38), NHDL (138.35 vs. 54.37 mg/dL), and ASM (18.54 vs. 17.67 kg) (all P<0.001). Strong associations with MetS persisted after adjustment (e.g., AIP: OR=161.59, 95% CI: 98.06–266.25). Nonlinear analysis revealed critical inflection points; for instance, the risk increase for VAI plateaued beyond 7.414. Mediation analysis identified NHDL as the strongest mediator, accounting for 60.3% of VAI&apos;s effect on MetS, while ASM mediated 12.6%. E-values indicated robustness to unmeasured confounding.ConclusionVisceral adiposity is strongly linked to MetS, a relationship significantly mediated by dyslipidemia (particularly NHDL) and altered muscle mass.The identified threshold effects offer potential clinical intervention targets, underscoring the importance of lipid profile management and muscle quality preservation in MetS prevention.</jats:p>