Objective: Subclinical and cli nical hypothyroidism are relatively common endocrine disorders in the general population. Subclinical hypothyroidism is defined as an elevated serum thyroid stimulating hormone (TSH) level associated with normal total or free T4 (fT4) and T3 (fT3) values. Thyroid hormones are known to play a regulatory role in the synthesis, metabolism, and mobilization of lipids. The effects of subclinical hypothyroidism on serum lipid values are less clear. The aim of this study was to compare whether clinical and subclinical hypothyroidism is associated with lipid levels and lipoprotein electrophoresis pattern.

Materials and Methods: We investigated 34 patients with subclinical hypothyroidism and 22 patients with clinical hypothyroidism. 44 female and 12 male patients were included in this study. Serum levels of fT3, fT4, TSH, total cholesterol (TC), HDL-cholesterol (HDL-C) and triglyceride (TG) were measured. LDL-cholesterol (LDL-C) level was calculated with Friedewald formula. Lipoprotein fractions were analysed by agarose gel electrophoresis.

Results: In 38% of subclinically hypothyroid and %36 of clinically hypothyroid patients TC levels were above the cut off value, these ratios were %29 and %18 for TG respectively. In %30 of subclinically hypothyroid and %19 of clinically hypothyroid patients HDL-C levels were under the cut off value.

Conclusion: There were no significant differences between the levels of TC, TG, HDL-C, LDL-C and alpha, prebeta and beta bands in clinical and subclinical hypothyroidism. As a result there are no significant differences between the tests of lipid panel and results of lipoprotein electrophoresis in subclinical and clinical hypothyroidism.