ECE2013 Poster Presentations Thyroid (non-cancer) (100 abstracts)
1Service of Endocrinology, Diabetes and Metabolism, São João Hospital Centre, Porto, Portugal; 2Department of Immunology, São João Hospital Centre, Porto, Portugal; 3Department of Health Information and Decision Sciences, São João Hospital Centre, Porto, Portugal; 4Faculty of Medicine, University of Porto, Porto, Portugal.
Objective: To examine whether Graves disease (GD) and autoimmune thyroiditis (AIT) are associated with insulin resistance and other cardiovascular risk factors.
Subjects and methods: We recorded thyroid function tests, BMI, insulin resistance markers comprising the homeostasis model assessment for insulin resistance (HOMA-IR and HOMA-B), the quantitative insulin sensitivity check index (QUICKI), hepatic insulin sensitivity index (HISI), whole-body insulin sensitivity index (WBISI), insulinogenic index (IGI) and the levels of total cholesterol (TC), HDL, LDL-cholesterol, triglycerides (TG), apolipoprotein B (ApoB), ApoA1, lipoprotein (a) (Lp(a)), homocysteine, CRP (C-reactive protein), folic acid and vitamin B12, in 57 patients with GD and subclinical hyperthyroidism (SCHyper), and in 83 patients with AIT and subclinical hypothyroidism (SCHypo). SCHypo was diagnosed based on raised TSH and normal free triiodothyronine (FT3) and free thyroxin (FT4) levels. SCHyper was diagnosed based in the context of normal FT3 and FT4 levels, with a TSH level suppressed below the normal range. A 75 g OGTT was performed in the morning, and blood samples were obtained every 30 min for 120 min for measurements of plasma glucose, insulin, and C-peptide. Statistical analysis was performed with MannWhitnney and Spearmans correlation tests. Results are expressed as mean±S.D. A two-tailed P value <0.05 was considered significant.
Results: Ninety-five percent of studied subjects were female. In the GD group, TSH levels were negatively correlated with TRAb levels (r=−0.28; P=0.04), and FT3 levels were positively correlated with HOMA-B (r=40; P=0.06). In this group, HOMA-IR and Lp(a) levels were positively correlated (r=0.33; P=0.02). In the AIT group, homocysteine levels were positively correlated with TSH levels (r=0.27; P=0.04), and negatively correlated with FT3 levels (r=−0.27; P=0.04). In this group, BMI was negatively correlated with WBISI (r=−0.37; P=0.004).
Conclusion: The interrelationships between thyroid function, insulin resistance, homocysteine, Lp(a), and CRP levels translate an increased cardiovascular risk in subclinical autoimmune thyroid disease.