Background: Autoimmune thyroiditis (AIT) is associated with increased risk of cardiovascular disease.
Objective: To evaluate the interrelationships between insulin resistance (IR) and other cardiovascular risk factors, such as high sensitivity CRP (C reactive protein) and homocysteine in patients with AIT.
Patients and methods: We analysed thyroid function, anti-thyroid antibodies, BMI, indices of IR, such as HOMA-IR, HISI (Hepatic Insulin Sensitivity Index), WBISI (Whole-Body Insulin Sensitivity Index), IGI (Insulinogenic Index), total cholesterol (TC), HDL-cholesterol, LDL-cholesterol, triglycerides (TG), ApoB, ApoA1, Lp(a), homocysteine, CRP, folic acid and B12 vitamin levels in 260 patients with AIT, 93.8% female, with a mean age of 47.2±14.8 years old and BMI 27.5±5.6 kg/m2. Each patient was submitted to an OGTT (75 g glucose) with measurements of glucose, insulin and C-peptide each 30 min, during 2 h. Statistic analysis was done with ANOVA and Pearson correlation tests. Results are expressed as mean±SD. A P<0.05 was considered significant.
Results: Analitical results are presented: TSH 3.680±11.877 UI/ml; FT3 2.94±0.99 pg/ml; FT4 1.52±1.84 ng/dl; C-peptide 2.62±1.04 ng/ml; TC 203.58±41.12 mg/dl; TG 117.27±83.87 mg/dl; HDL-cholesterol 57.08±14.87 mg/dl; ApoA1 145.24±29.71 mg/dl; ApoB 97.02±24.36 mg/dl; Lp(a) 28.21±32.22 mg/dl; CRP 0.47±0.83 mg/dl. We found positive significant correlations between IGI and anti-TPO (r=0.179; P=0.005), C-peptide (r=0.463; P<0.001), TG (r=0.227; P<0.001), CRP (r=0.162; P=0.02) and TSH (r=0.126, P=0.048) levels. HISI results positively correlated with TSH (r=0.173; P=0.006). We also detected significant negative correlations between WBISI and TG (r=−0.191; P=0.003), and CRP (r=−0.181; P=0.008) levels.
Conclusion: The interrelationships between thyroid function, insulin resistance, lipid profile and inflammation may explain the increased cardiovascular risk associated with AIT.
Prague, Czech Republic
24 - 28 Apr 2010
European Society of Endocrinology