Association of Thyroid Disorders with Glycemic and Lipid Profiles in Subjects with Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) and cardiovascular diseases (CVD) share an underlying pathology with thyroid dysfunction, affecting glycemic and lipid profiles, particularly in rapidly transitioning populations. This study, conducted at a tertiary care hospital in Dhaka, Bangladesh, explored the association of thyroid disorders with glycemic and lipid profiles in subjects with T2DM. Blood samples from 172 subjects (75% male and 25% female) were analyzed for fasting plasma glucose (FPG), plasma glucose after breakfast (PGABF), glycated hemoglobin (%HbA1c), lipid profiles, and thyroid-stimulating hormone (TSH) levels. Subjects were categorized as euthyroid, hypothyroid and hyperthyroid groups according to TSH levels. The euthyroid group had FPG 6.1±0.8 mmol/L, PGABF 7.5±1.3 mmol/L, and HbA1c 6.2±0.5%, while higher FPG was observed in hypothyroid [10.3±4.2 (p < 0.001)] and hyperthyroid [10.3±4.6 (p = 0.001)] groups, along with increased PGABF and HbA1c levels. The euthyroid group presented with 52% elevated total cholesterol, 45% elevated triglycerides, 41% low high-density lipoprotein (HDL) cholesterol, and 51% elevated low-density lipoprotein (LDL) cholesterol. Notably, the hyperthyroid group showed 87% elevated serum triglycerides (p < 0.001), whereas the hypothyroid group had 23% elevated serum total cholesterol (p < 0.001). Findings indicate thyroid disorders are linked to elevated plasma glucose and HbA1c, with hyperthyroidism potentially elevating triglycerides in T2DM.