Volume 4,Issue 3
Association between White Blood Cell Count and Remnant Cholesterol Inflammatory Index in Middle-Aged and Older Adults: A Cross-National Database Study Using NHANES and CHARLS
Objectives: The remnant cholesterol inflammatory index (RCII) is a novel composite biomarker that integrates lipid residual risk and inflammatory status. White blood cell (WBC) count, one of the most routine clinical inflammatory indicators, has an undefined association with RCII and unknown joint prognostic significance. This study aimed to investigate the cross-sectional association and longitudinal prognostic implications of WBC and RCII in middle-aged and older populations, so as to deepen the understanding of the “lipid-inflammation” cycle. Methods: Cross-sectional analyses were performed in two cohorts of adults aged 45 years and older: NHANES (2015–2016, n = 2,839) and CHARLS (2011, n = 5,955). Multivariable logistic regression and restricted cubic spline (RCS) analyses were used to assess the association and its nonlinearity. Longitudinal analyses utilized CHARLS follow-up data (2011–2015), applying Kaplan-Meier curves and Cox proportional hazards models to examine differences in long-term survival across categories of RCII and WBC. Results: In fully adjusted models, WBC was significantly and positively associated with RCII in both cohorts (NHANES: OR = 1.097, 95% CI: 1.038–1.158; CHARLS: OR = 1.309, 95% CI: 1.266–1.354). RCS analyses further revealed a nonlinear relationship. Longitudinal analyses demonstrated a noteworthy interactive phenomenon: in the low RCII group, individuals with high WBC exhibited significantly lower 5-year survival than those with low WBC, whereas in the high RCII group, the survival curves for different WBC levels tended to overlap. Conclusion: WBC count is nonlinearly and positively associated with RCII in both U.S. and Chinese middle-aged and older adults, with elevated WBC independently predicting higher mortality specifically in low-RCII individuals. This supports WBC as a low-cost adjunctive marker for risk stratification and highlights its prognostic value beyond RCII alone.
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