Lipid Profile Abnormalities in Hypothyroidism

The present investigation was conducted to study the contributive role of clinical and subclinical hypothyroidism in causing dyslipidemia. A total of 220 clinical hypothyroidism patients, 146 subclinical hypothyroids and 200 euthyroid controls, with a mean age of 39 years (range25 – 55 years) were included. The thyropropin, triiodothyronine and thyroxine levels of the patients were assayed by enzyme immunoassay method on ELISA Reader and lipid profile of the patients was estimated by enzymatic colorimetric method. The clinical hypothyroid patients exhibited decline in T3 and T4 concentration (T3 < 0.80 ng/ml, T4 < 4.5 μg/dl) and elevation in TSH level (TSH > 6 mIU/dl) whereas subclinical hypothyroidism patients have high thyrotropin concentration (TSH >6 mIU/dl) with normal thyroxin and triiodothyronine levels. The patients with clinical hypothyroidism exhibited significant increase in concentration of total cholesterol ((p<0.0001), LDL (p<0.0001) and triglycerides (p<0.0001), whereas HDL (p<0.0001) showed a decrease in its concentration in comparison to euthyroid controls. A decline in the the hepatic lipase activity (p<0.0001) was also noted. Subclinical hypothyroid patients revealed significant increase in concentration of total cholesterol (p<0.0001), LDL (p<0.0001) and triglycerides level (p<0.0001). Non significant decrease in HDL was observed in subclinical hypothyroid patients. We have found that hypothyroidism is associated with an atherogenic lipid and lipoprotein profile, characterized by an increase in concentration of total cholesterol, LDL and triglycerides and by decrease in HDL levels.