Can high normal TSH level predispose to hypercholesterolemia?

Background: Thyroid hormone plays an important role in carbohydrate, protein, and lipid and electrolyte metabolism. Studies have demonstrated the association of hypothyroidism with dyslipidaemia. However the impact of high normal TSH on lipid profile is lacking. Also, thyroid hormone is known to influence glomerular filtration rate, and renal electrolyte handling. So, this study compared TSH levels in normal ranges with fasting lipid profile and electrolytes. Objectives: To measure and compare the levels of serum TSH, fasting lipid profile and electrolytes in euthyroid individuals with normal TSH and to correlate serum TSH with lipid profile and electrolytes across different age groups in both sexes. Materials and methods: After obtaining ethical clearance, 2 ml of fasting venous blood sample was drawn from 200 subjects (males=100, females=100) aged between 20-75years who consented to participate. Serum was used for estimation of TSH, lipid profile and electrolytes. TSH was measured by 4th generation Immunoassay in Cobas 6000 e601 autoanalyzer (Roche). The lipid profile and electrolytes were assayed in Cobas 6000 c501 autoanalyzer (Roche). Results: Serum TSH values showed significant positive correlation with total cholesterol (p=<0.001), triglycerides (p=<0.001) and LDL cholesterol (p=<0.001), but did not show any significant correlation with HDL cholesterol. Also serum TSH showed significant negative correlation with sodium (r=-0.185, p=0.048) and potassium (r=-0.205, p=0.028) levels. Conclusion: TSH and thyroid status can influence lipid and electrolyte metabolism. High normal TSH level may predispose to hypercholesterolemia and hypertriglyceridemia. High normal TSH patients can have lower serum electrolytes.