The association of serum thyroid stimulating hormone and serum lipids and lipoproteins in patients with suspected hypothyroidism.

Serum levels of thyroid stimulating hormones (TSH), cholesterol, triglycerides, lipoproteins and high density lipoprotein subfractions were determined in 80 patients and 150 age and sex matched controls. The lipids and lipoproteins distribution showed a significant increase in total cholesterol and LDL-C levels in the patient group (p < 0.001). In contrast the HDL-C and its subfractions (HDL2-C and HDL3-C) were significantly lower in the patient groups (p < 0.001). The ratio of HDL-C:total cholesterol was significantly higher in the control group (p < 0.001). This is suggestive of low HDL-C in hypothyroid patients and a high HDL-C in the control group. The relationship of TSH and lipids or lipoproteins indicates a positive association. These results suggest that thyroid dysfunction exerts atherogenic effects through the metabolism of cholesterol. Furthermore, the study indicates that the ratios of HDL and its subfractions of total cholesterol and LDL provide additional parameters for the assessment of the risk of developing coronary heart disease.