Insulin resistance, lipid profile, C-reactive protein and homocysteine in patients with autoimmune thyroiditis and subclinical hypothyroidism
Celestino Neves1,2, Marta Alves1,2, Ema Carvalho1, Isolina Pimentel1, Miguel Pereira1, Renata Ramalho1,2, Carmo Palmares1,2, Cristina Guimarães1,2, João Ramos1,2, Davide Carvalho1,2, Luís Delgado1,2 & José Luís Medina1,2
Background: Thyroid function, insulin resistance, serum lipid, C-reactive protein (CRP) and homocysteine are associated with an increased cardiovascular risk in patients with autoimmune thyroiditis (AIT).
Objective: To evaluate the interrelations between thyroid function, insulin resistance, serum lipid concentrations, CRP and homocysteine in patients with AIT and subclinical hypothyroidism.
Subjects and methods: We recorded thyroid function tests, BMI and the levels of total cholesterol (TC), HDL, LDL-cholesterol, triglycerides (TG), apolipoprotein B (ApoB), ApoA1, lipoprotein (a) (Lp[a]), homocysteine, CRP, folic acid, vitamin B12, and insulin resistance markers comprising the HOMA-IR, HISI (Hepatic Insulin Sensitivity Index), WBISI (Whole-Body Insulin Sensitivity Index), IGI (Insulinogenic Index) in 500 patients with AIT, with a mean age of 47.2±14.8 years. 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 ANOVA and Pearsons Correlations test. A two-tailed P value < 0.05 was considered significant.
Results: TSH levels were 3.680±11.877 UI/ml and BMI was 27.5±5.6 kg/m2. There were significant positive correlations between TSH and serum TC (r=0.167; P<0.001), LDL (r=0.131; P=0.004), TG (r=0.168; P<0.001), and ApoB (0.141; P=0.008). We found significant positive correlations between IGI and anti-TPO (r=0.179; P=0.005), CRP (r=0.162; P=0.02), and TSH (r=0.126; P=0.048). We also found significant positive correlations between HISI and TSH (r=0.173; P=0.006), and significant negative correlations between WBISI and CRP (r=−0.181; P=0.008).
Conclusions: In patients with AIT, there are positive associations between the levels of TSH, the lipid profile, and insulin resistance markers, such as IGI, and HISI.