Association of the Neutrophil to High-Density Lipoprotein Cholesterol Ratio and Platelet to High-Density Lipoprotein Cholesterol Ratio with Early Vascular Aging

Purpose: This cross-sectional study aimed to investigate the association of complete blood count parameters and lipid metabolism‑related inflammatory indices with early vascular aging (EVA). Methods: A total of 1114 participants were included with an overall EVA prevalence of 19.6%. Logistic regression was adopted to assess the independent associations of neutrophil to high-density lipoprotein cholesterol ratio (NHR) and platelet to high-density lipoprotein cholesterol ratio (PHR) with EVA after adjusting for traditional cardiovascular risk factors. Restricted cubic spline (RCS) models were applied to examine nonlinear relationships. Subgroup analyses were conducted to evaluate effect modification, and decision curve analysis (DCA) was used to assess the net benefit for risk stratification. Results: In the fully adjusted model, both NHR (OR = 1.583, 95% CI: 1.078-2.327, P = 0.019) and PHR (OR = 2.050, 95% CI: 1.325-3.173, P = 0.001) remained independently associated with increased odds of EVA. The RCS analysis did not reveal significant nonlinear relationships for either biomarker (P for non-linearity > 0.05), suggesting that the associations were adequately captured by linear models. Subgroup analyses revealed that the positive association between NHR and EVA risk was more pronounced in men and smokers. For PHR, there was no significant interaction among different subgroups. DCA demonstrated that both NHR and PHR conferred modest net benefit gains (maximum 0.0127 and 0.0162, respectively) across clinically relevant threshold probabilities. Conclusion: In this cross‑sectional population, both NHR and PHR were independently associated with EVA, with essentially linear dose‑response relationships. The association between NHR and EVA was particularly significant in men and smokers, showing population heterogeneity. Both indices provided a modest net benefit for identifying individuals with EVA, but the modest magnitude of this benefit suggests limited immediate clinical utility. Limitations include the cross‑sectional design and single‑center cohort, which limit causal inference and generalizability. Further prospective, multi‑center studies are needed to validate these findings.