Evaluation of interrelationships between thyroid function, lipid profile, homocysteine and high sensitivity C-reactive protein in patients with autoimmune thyroiditis
Celestino Neves1, Marta Alves1, Miguel Pereira1, Ema Carvalho1, Isolina Pimentel1, Renata Ramalho2, Carmo Palmares2, Cristina Guimarães2, João Pedro Ramos2, Davide Carvalho1, Luís Delgado2 & José Luís Medina1
Background: Thyroid dysfunction and lipid profile are associated with cardiovascular disease in patients with autoimmune thyroiditis (AIT).
Objective: To evaluate the association between thyroid function, lipid concentrations, C-reactive protein (CRP) and homocysteine in patients with AIT.
Patients and methods: We assessed thyroid function tests, BMI, total cholesterol (TC), HDL-cholesterol, LDL-cholesterol, triglycerides (TG), apolipoprotein B (ApoB), apolipoprotein A1 (ApoA1), lipoprotein (a) [Lp (a)], homocysteine, CRP, folic acid and B12 vitamin in 500 patients with AIT, 93.6% female, with a mean age of 46.7±15.8 years old and BMI 27.0±5.4 kg/m2. Statistic analysis was done with ANOVA and Pearson correlation tests. Results are expressed as mean±SD or percentage. A P<0.05 was considered significant.
Results: We found significant positive correlations between TSH and TC (r=0.167; P<0.001), LDL-cholesterol (r=0.131; P=0.004), TG (r=0.168; P<0.001) and ApoB (0.141; P=0.008). BMI was positively correlated with free T4 (FT4) (r=0.125; P=0.005), ApoB (r=0.152; P=0.004), TG (r=0.193; P<0.001) and LDL-cholesterol (r=0.141; P=0.002), and was negatively correlated with HDL-cholesterol (r=−0.238; P<0.001), ApoA1 (r=−0.129; P=0.01) and FT3 (r=−0.103; P=0.02). We also found negative correlations between CRP and ApoA1 (r=−0.183; P=0.01), B12 vitamin (r=−0.158; P=0.005) and FT3 (r=−0.176; P<0.001), and significant positive correlations between CRP and folic acid (r=0.858; P<0.001), FT4 (r=0.168; P=0.001) and anti-TPO antibodies (r=0.120; P=0.01). We did not find significant correlations with homocysteine.
Conclusion: In patients with AIT the interrelationships between thyroid function and TC, LDL-cholesterol, TG, ApoB and CRP determine an increased cardiovascular risk. Thus, diagnostic and therapeutic strategies should be implemented to minimize the impact of AIT, which has a high prevalence in the general population.