A cross-sectional analysis of remnant cholesterol-diabetes association in US adults

The relationship between remnant cholesterol and diabetes is a critical issue in the fields of health and public health. Currently, the relationship between remnant cholesterol (RC) and diabetes is a highly researched and trending topic. The aim of this study was to investigate association between RC and diabetes in US individuals. The secondary objective of this study was to explore the potential dose-response relationship between the exposure RC and diabetes. Our study utilized all available continuous data from the National Health and Nutrition Examination Survey (NHANES) from 2013 to 2018. Multivariable logistic regression models were used to investigate the association between RC and diabetes. The association between RC and diabetes was assessed using smoothing splines generated by generalized additive models. Additionally, a threshold effect analysis of the relationship between RC and diabetes was conducted. Analysis of 6,875 eligible adults (derived from an initial cohort of 7,780 after exclusions for missing diabetes/cholesterol data) revealed a significant threshold effect at 19 mg/dLof remnant cholesterol (RC) for diabetes prevalence. Participants with RC < 19 mg/dL exhibited substantially elevated diabetes odds in both unadjusted (OR = 1.80, 95% CI: 1.57-2.06; P < 0.001) and fully adjusted models (OR = 1.46, 95% CI: 1.30-1.64; P < 0.001), whereas RC ≥ 19 mg/dL demonstrated no significant association (adjusted OR = 0.99, 95% CI: 0.88-1.25; P = 0.96). Quartile analysis confirmed a robust dose-dependent relationship: compared to Quartile 1 (RC ≤ 12 mg/dL; reference), diabetes odds progressively increased to OR = 1.72 (95% CI: 1.37-2.16)​for Quartile 2 (13-18 mg/dL), OR = 2.32 (95% CI: 1.86-2.91) for Quartile 3 (19-26 mg/dL), and OR = 3.42 (95% CI: 2.77-4.21)​for Quartile 4 (27-80 mg/dL), with significant trend persistence after multivariable adjustment (P < 0.001). These associations remained significant despite substantial demographic variations across RC quartiles, including differences in age (P < 0.001), sex distribution (P < 0.001), and racial/ethnic composition (P < 0.001). This cross-sectional analysis observed that elevated RC levels were significantly associated with higher prevalence of diabetes in adults aged 20-80 years, with a threshold value of 19 mg/dL for increased association strength. The findings support RC as a metabolic marker associated with prevalent diabetes with a threshold value of 19 mg/dL for strengthened association.