Effect of Hypothyroidism on Lipid Profile and Liver Enzymes: Implications In Non-Alcoholic Fatty Liver Disease

Hypothyroidism is known to affect lipid metabolism, and its association with non-alcoholic fatty liver disease (NAFLD) is of growing interest. This study aimed to evaluate the effects of hypothyroidism on lipid profiles and liver enzymes, with a particular focus on the implications for NAFLD.

A case-control study was conducted with 74 participants, including 44 hypothyroid patients (22 with overt hypothyroidism and 22 with subclinical hypothyroidism) and 30 healthy controls. Participants were aged 20-65 years, and a detailed clinical history was obtained to exclude comorbid conditions such as diabetes, liver disorders, alcohol consumption, and acute inflammatory diseases. Waist circumference, BMI, and blood pressure were measured, and venous blood samples were drawn for analysis. Thyroid hormones (TSH, T3, T4) were measured using enzyme-linked fluorescent assays, while lipid profile (cholesterol, triglycerides) and liver enzymes (ALT, AST, ALP) were assessed using an automated clinical analyzer. Statistical analysis included ANOVA, post-hoc tests, and correlation analysis.

Significant differences were observed in TSH levels between the groups (p < 0.001), with the overt hypothyroid group showing the highest mean TSH. BMI was higher in the hypothyroid groups compared to controls, but the difference was not statistically significant (p = 0.065). Cholesterol levels were significantly elevated in both the overt and subclinical hypothyroid groups (p = 0.032), with post-hoc analysis revealing significant differences between the overt hypothyroid group and controls (p = 0.016). No significant differences were found in triglyceride levels across groups (p = 0.191). Outlier analysis of TSH levels revealed several extreme values in the overt hypothyroid group, reflecting more severe thyroid dysfunction. Correlation analysis showed a weak positive correlation between TSH and BMI (r = 0.18, p = 0.044), while no significant correlations were observed between TSH and age, or BMI and age.

Hypothyroidism, particularly overt hypothyroidism, is associated with altered lipid metabolism and higher cholesterol levels. These changes may contribute to an increased risk of NAFLD in individuals with thyroid dysfunction.