Novel Biomarkers for Assessing the Risk of Cardiovascular Disease in Individuals with Thyroid Dysfunction: Non-High-Density Lipoprotein Cholesterol Versus Non-High-Density Lipoprotein Cholesterol/High-Density Lipoprotein Cholesterol Ratio

Objectives: Both the non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol-C ratio (NHHR) and non-high-density lipoprotein cholesterol (HDL-C) are important indicators for assessing cardiovascular disease (CVD) risk. Non-HDL-C provides a comprehensive evaluation of all cholesterol particles that could contribute to plaque formation, while NHHR indicates the balance between atherogenic and protective cholesterol. This study aimed to assess and compare NHHR and non-HDL-C as indicators for assessing the risk of CVD in individuals with thyroid disorders. Material and Methods: In this case-controlled study, 122 subjects were recruited. The group included 62 individuals diagnosed with thyroid dysfunction and 60 healthy controls matched for gender and age, all aged between 20 and 65 years. Anthropometric variables such as body mass index (BMI), waist circumference (WC), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were measured. In addition, free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), total cholesterol (TC), triglycerides (TG), and HDL-C were estimated using standard procedures. Low-density lipoprotein cholesterol (LDL-C), very LDL-C (VLDL-C), nonHDL-C, and other atherogenic indices were calculated. Significant difference was pegged at p < 0.05. Results: Mean values of DBP, SBP, WC, BMI, TC, fasting blood glucose, TG, non-HDL-C, TSH, LDL-C, high-sensitive C-reactive protein, VLDL-C, interleukin 6, and other atherogenic indices were significantly higher ( p < 0.05) in subjects compared to controls; mean values of HDL-C, FT3, and FT4 were significantly decreased ( p < 0.05). Non-HDL-C and NHHR showed a significant positive correlation with TSH and lipid profile parameters ( p < 0.05), but a non-significant negative correlation with BMI, FT3, and FT4. The receiver operating characteristic analysis indicated that all atherogenic indices were better at assessing CVD risk than lipid profile parameters, with an area under the curve >0.7. Logistic regression showed that NHHR (odds ratio: 5.46; 95% confidence interval: 4.168–16.798; p < 0.001) was the most significant independent predictor of CVD risk. Conclusion: All atherogenic indices examined showed significant correlation with lipid profiles and thyroid hormones in individuals with thyroid dysfunction. However, the NHHR outperformed traditional lipid parameters and other atherogenic indices, making it a more sensitive indicator of CVD risk assessment and dyslipidemia.