Thyroid function tests in metabolic syndrome

OBJECTIVE: We evaluated the thyroid function tests in individuals with metabolic syndrome to explore the possibility of thyroid receptor resistance. MATERIALS AND METHODS: The study was a cross-sectional study. It included 40 patients (group I) and 20 healthy individuals served as controls (group II). Patients in group I fulfilled the three or more of the NCEP ATP III (National Cholesterol Education Programme – Adult Treatment Panel III) criterion to define the metabolic syndrome. Blood sugar and serum insulin levels were measured in both the groups. All the patients (group I) had insulin resistance as per the HOMA IR (the homeostasis model for insulin resistance) model. The HOMA IR value obtained in group II individuals served as a reference mark to define insulin resistance. T(3), T(4), TSH levels were measured as indicators of thyroid functions. There was an increase in TSH levels with normal T(3) and T(4) in group I indicating that increased TSH probably due to thyroid receptor resistance may be a part of metabolic syndrome rather than a state of hypothyroidism. RESULTS: T(3) and T(4) levels were comparable in patients and controls. There was a significant increase in TSH levels in patients as compared to the controls. CONCLUSION: Raised TSH in patients with metabolic syndrome independent of lowered T(3) and T(4) suggest it to be a part and parcel of this syndrome.