Association Between Neutrophil‐To‐ HDL Cholesterol Ratio and Insulin Resistance in Individuals With Obesity: Cross‐Sectional Study of Chinese and U.S. Cohorts

This study aimed to evaluate whether the neutrophil-to-high-density lipoprotein cholesterol ratio (NHR) is independently associated with Insulin Resistance (IR) among individuals with obesity and to examine the robustness of this association across distinct populations. Two independent cohorts were analyzed: a Chinese training cohort (n = 764) and a US validation cohort from the National Health and Nutrition Examination Survey (NHANES; n = 2963). Multivariable logistic regression and restricted cubic spline (RCS) models were applied to assess associations between NHR and IR. Subgroup analyses evaluated consistency, and receiver operating characteristic (ROC) curves assessed predictive performance. NHR was positively associated with IR in both cohorts. After full adjustment, each unit increase in NHR was associated with a 23% higher IR risk in the training cohort (OR = 1.23, 95% CI: 1.10-1.38) and a 21% higher risk in the validation cohort (OR = 1.21, 95% CI: 1.09-1.35). Participants in the highest NHR quartile had markedly increased IR risk compared with the lowest quartile (training: OR = 4.45, 95% CI: 2.27-8.69; validation: OR = 2.04, 95% CI: 1.37-3.03). RCS analysis indicated a linear association in the training cohort and a nonlinear pattern in the validation cohort. Associations were consistent across subgroups. NHR showed modest predictive ability (AUC: 0.677 and 0.654). NHR demonstrated a significant positive association with insulin resistance in Chinese and US obese cohorts, indicating its potential utility as a biomarker for IR and associated diseases.