The effect of thyroid hormones on structural changes in the liver through metabolic alterations in patients with hypothyroidism

Metabolic dysfunction-associated fatty liver disease is one of the most widespread chronic liver diseases globally and is one of the main factors causing structural changes in the liver. Considering that thyroid hormones influence metabolic processes in the liver through beta-1 thyroid receptors, the relationship between markers of metabolic changes and structural liver alterations in patients with hypothyroidism has still not been fully clarified. The aim of this study was to investigate the relationship between thyroid function hormones, including TSH, free T3, free T4, and their ratio, and structural liver changes assessed by FibroScan parameters through metabolic indicators. A total of 93 patients were examined, of whom 63 underwent FibroScan assessment. Thyroid function parameters, including TSH, free T4, free T3, and the free T3/free T4 ratio, as well as BMI, HOMA-IR, and lipid profile, were evaluated. According to thyroid function status, patients were divided into hypothyroid (n=48) and euthyroid (n=45) groups.

According to thyroid status, free T3 was found to be associated with the FibroScan CAP parameter (ρ=0.249; p=0.051). Liver fibrosis was associated with BMI (ρ=0.337; p=0.007) and triglyceride levels (ρ=0.281; p=0.032). BMI (ρ=0.584; p<0.001), HOMA-IR (ρ=0.506; p<0.001), and triglycerides (ρ=0.366; p=0.005) were identified as predictors of hepatic steatosis. No direct effect of thyroid hormones on structural liver changes was identified. However, in patients with hypothyroidism, metabolic alterations, such as increased BMI, insulin resistance, and hypertriglyceridemia, were found to play a significant role in the development of structural liver changes, including steatosis and fibrosis.