Correlation of sdLDL-C with cardiometabolic risk indices in women with subclinical hypothyroidism– A cross-sectional study

Introduction and Aim: Subclinical hypothyroidism (SCH) characterised by normal free thyroxine (FT4), “free triiodothyronine (FT3)”, and raised serum TSH, is an early stage of mild thyroid hormone deficiency. A change in the lipid profile most often observed in SCH is mainly caused by increased serum levels of Triglycerides (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C), whereas high-density lipoprotein cholesterol (HDL-C) levels can be normal or elevated. Studies on small dense Low-Density Lipoprotein – Cholesterol (sdLDL-C), associated with CVD risk are few. The aim of this study was to estimate serum sdLDL-C and find its correlation with thyroid profile (FT4 and TSH) and cardiometabolic risk indicators in female subjects with subclinical hypothyroidism. Materials and Methods: The study had 112 female participants in total. After screening, subjects were divided into two groups. Control group (euthyroid) and study group (SCH). Age, TSH, FT4, TC, TG, HDL-C, LDL-C, sdLDL-C & Lipid ratios “(TC/HDL-C, LDL-C/HDL-C”, “Log TG/ HDL-C)” were examined and compared between the two groups. Results: The correlation of sdLDL-C with TSH, FT4, lipid parameters & lipid ratios were studied. TG, TC, HDL-C, and LDL-C were not clinically significant. While sdLDL-C and lipid ratios had a statistical decrease, it was not clinically significant. A highly significant negative association between sdLDL-C, other lipid parameters, except HDL-C, lipid ratios are observed in the study group. Conclusion: As anticipated, the current investigation did not demonstrate any statistically significant improvement in the sdLDL-C as a better predictor of CVD risk. No apparent lipid abnormalities were also seen in women, in the age group of 20-40 years as observed in the correlation studies. However, measurement of AIP along with FT4 would make a better assessment of CVD risk.