Estimation of Thyroid Profile and Serum Fasting Insulin in Newly Detected Hypothyroid Adults: A Case Control Study

Abstract

Background: Thyroid hormone inuences glucose homeostasis by modications of the circulating insulin levels and peripheral tissues uptake of glucose. Thyroid function has been associated with insulin resistance. There is infrequent information about thyroid function in relation with glucose homeostasis in young adults. Objective: To evaluate the thyroid prole, fasting serum insulin, HOMA-IR, Fasting blood sugar among newly detected hypothyroid adults (cases) in comparison with normal healthy adults (controls). Methodology: A case control study of 164 subjects was carried out on hypothyroid adults (n=82) and controls (n=82), general medicine OPD, RRMC & hospital, Bengaluru. Fasting blood samples were taken. Thyroid prole, serum fasting insulin was done with CLIA. HOMA-IR was employed to assess the level of insulin resistance. Results: The study subjects with mean age of 35 years and female predominance. TSH levels were higher in cases as compared to controls (p<0.01). However, the value of both T3 and T4 levels were found to be lower in cases as compared to controls and the difference of T3 between the groups was statistically signicant (p=0.03) while that of T4 was not signicant (p=0.07). FT3 & FT4 levels were within the reference range. Serum fasting insulin levels and HOMA-IR levels were higher in cases than controls (p=0.007) and (p<0.01) respectively. A strong positive correlation was found between TSH and insulin (r=.528, p<.01), TSH and HOMA-IR (r=.462, p<.01), insulin and HOMA-IR (r=.962, p<.01). Conclusion: Our study shows that hypothyroidism is common among females and associated with mild degree of insulin resistance as reected by HOMA-IR.