Small Dense Low-Density Lipoprotein Level in Newly Diagnosed Type 2 Diabetes Mellitus Patients With Normal Low-Density Lipoprotein

Abstract

Background and objective There are three subtypes of low-density lipoprotein (LDL): large buoyant (lb), intermediate, and small dense (sd). Among these LDL subtypes, small dense low-density lipoprotein (sdLDL) has been proven to be an independent risk factor for atherosclerosis. Type 2 diabetes mellitus (T2DM) encompasses several metabolic abnormalities and patients suffering from T2DM without good glycemic control are prone to develop atherosclerosis. Hence, in T2DM, it is recommended to evaluate blood lipids for early detection of hyperlipidemia to identify the risk. A larger percentage of sdLDL in T2DM patients with an optimal or near-optimal LDL level might be a hidden risk factor for atherosclerosis. Hence, we aimed to find the level of sdLDL cholesterol (sdLDL-C) among newly diagnosed T2DM patients with optimal or near-optimal blood lipids and to compare it with age and sex-matched controls. Materials and methods In this study, we enrolled newly diagnosed T2DM patients from the diabetic clinic of a tertiary care hospital. The patients were then tested for blood lipids, namely, total cholesterol, triglyceride, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol (LDL-C), including sdLDL-C. Then, age and sex-matched controls with similar baseline lipid levels to the T2DM group (without sdLDL-C) were recruited. After recruitment, both groups were measured for blood lipids including sdLDL-C in a single day. The level of sdLDL-C between the groups was tested statistically by the Mann-Whitney U test. Results A total of 50 T2DM patients with a median age of 36 years (Q1-Q3: 33.75-41) were included as the study group and 50 age and sex-matched controls with a median age of 34 years (32-37.25; p = 0.09) were recruited. The median fasting glucose was 165 (Q1-Q3: 145-199.25) mg/dL and 90.5 (Q1-Q3: 87.75-95.25) mg/dL (p < 0.0001) in the study and control groups, respectively. The LDL-C was 109.9 (Q1-Q3: 99.4-119.4) mg/dL and 108.5 (Q1-Q3: 87.55-124.1) mg/dL (p = 0.94) in the study and control groups, respectively. The sdLDL-C was 40.11 (Q1-Q3: 36.28-43.58) mg/dL and 24.64 (Q1-Q3: 22-32.49) mg/dL (p < 0.0001) in the study and control groups, respectively. Conclusion Newly diagnosed T2DM patients with blood lipids within an optimum or near-optimum level may have a higher percentage of sdLDL-C when compared with healthy controls. Hence, they may have a higher risk of atherosclerosis and cardiovascular diseases. Clinicians may miss the potential risks if they do not advise the sdLDL-C component of LDL-C while advising for the test for blood lipid.