Endocrine Abstracts

Introduction: Level of TSH respond to fluctuations in serum free (FT₄) but remain in a very narrow individial range. Thyroid function tests are intrinsically linked to variables of insulin resistance and endothelial function. It is possible that underlying factors lead simultaneously to increased serum TSH, insulin resistance, even within current normal TSH levels.

Description of methods and design: We aimed intestigate the patients with upper limit TSH and insulin resistance in patients of our out-patients clinics of endocrinology where they were adressed for obesity. Serum insulin, C-peptide and TSH Levels were measured by chemiluminescence method on advia centour XP and HbA1C measured by immune – inhibition on Advia 2400 chemistry system (Siemens Healtcare Diagnostics Inc).

Results and conclusion: Some characteristics of study group (means ±S.D.) (totaly 152 patients): age (years): 49.7±14.8, systolic blood pressure (mm/Hg): 128.8±19.2, diastolic blood pressure (mm/Hg): 78.3±9.6, fasting blood glucose (mg/dl): 110.3±48, HbA1C (%): 5.74±1.35, insulin (μU/ml): 12.2±11.4, C-peptide (ng/ml): 3.04±1.71, TSH (μIU/ml):2.56±2.7, FT₄ (ng/ml): 1.28±0.47, weight (kg): 84.5±18.7, BMI (kg/m²): 32.2±7.5, circumference of waist (cm): 98.9±16.3, WHR (waist/hip ratio): 0.87±0.07. When we divided into two group according to TSH levels. We found hyperinsulinemia (P<0.04), elevated C-peptide levels (P<0.01), and WHR (P<0.04) in the second group. This findings could justify the increased risk for insulin resistance associated disorders, such as cardiovascular disease, observed in patients with high TSH levels.