Insulin resistance assessed by estimated glucose disposal rate and risk of coronary artery calcification in middle-aged participants without diabetes undergoing health check-ups

Background and aims Insulin resistance, assessed by estimated glucose disposal rate (eGDR), is linked to atherosclerosis, yet evidence primarily comes from diabetic populations. The aim of this study was to investigate the association between eGDR and coronary artery calcification (CAC) in non-diabetic adults. Methods In this cross-sectional study, 4750 participants aged 40–65 years without diabetes were enrolled from Jinling Hospital between 2022 and 2024. CAC was assessed via CT scans. Multivariable Logistic regression and restricted cubic splines were used to analyze the relationship of eGDR with CAC prevalence and severity. Results The mean age was 47.98 ± 6.61 years; 79.31% were male, and 665 participants (14.0%) had CAC. After multivariable adjustment, lower eGDR was significantly associated with higher CAC risk. Each 1-unit increase in eGDR was associated with a 9% risk reduction (OR = 0.91, 95% CI: 0.84–0.98, P = 0.02). Compared to the lowest eGDR quartile (Q1), the odds ratios for Q2, Q3, and Q4 were 0.84 (0.66–1.07), 0.69 (0.52–0.92), and 0.63 (0.44–0.90), respectively ( P for trend = 0.004). Tobit regression confirmed an inverse association between eGDR and CACS (β = -4.07, P = 0.0002). Multivariate ordered Logistic regression analysis revealed that after adjusting for multiple factors, eGDR was significantly associated with the severity of CAC, both as a continuous variable (mild CAC: OR = 0.90, 0.83–0.97; moderate-to-severe CAC: OR = 0.86, 0.78–0.95) and across quartiles ( P for trend = 0.03). A nonlinear dose-response relationship was observed ( P for nonlinearity = 0.01), with CAC risk increasing as eGDR fell below 10.8. Conclusion Lower eGDR is independently associated with increased prevalence and severity of CAC in non-diabetic middle-aged Chinese adults.