Plasma CRP, apolipoprotein A-1, apolipoprotein B and Lp(a) according to thyroid function status

Suh, Jung Yul; Lee, Won Young; Park, Jeong Sik; Kim, Sun Woo

Abstract

BACKGROUND: Alterations of lipid profiles are well known in thyroid dysfunction. Hypothyroidism is associated with premature atherosclerosis. This relation has been attributed to increased levels of total cholesterol, low density lipoprotein cholesterol and apolipoprotein B. However, there have been dissenting reports of abnormalities in serum lipid concentrations in patients with subclinical hypothyroidism. Serum Lp(a), an independent risk factor of atherosclerosis, is predicted according to thyroid function status. C-reactive protein (CRP) is very sensitive acute phase reactant and independently associated with the occurrence of atherosclerosis. Overt hypothyroidism is a cause of atherosclerosis, so it is expected that serum level of CRP may be related with thyroid dysfunction. However, no study has been performed about it. The objective of the study was to evaluate the relation of plasma CRP, apo A1, apo B and Lp(a) with thyroid function.
METHODS
We undertook this study in 54 patients with hyperthyroidism, 35 patients with subclinical hyperthyroidism, 29 patients with overt hypothyroidism, 194 patients with subclinical hypothyroidism and 100 age and sex matched healthy control subjects. Serum CRP and Lp(a) were measured by immuno-nephelometry.
RESULTS
There were no significant differences of serum CRP, Lp(a), HDL-C and apo A1 according to thyroid dysfunction. Serum total cholesterol level was lower in hyperthyroidism than in overt hyperthyroidism, subclinical hypothyroidism, subclinical hyperthyroidism and healthy control subjects (p<0.05). Serum LDL-C level was lower in hyperthyroidism than overt hypothyroidism (p<0.05). Serum triglyceride level was higher in overt hypothyroidism than in hyperthyroidism and healthy control subjects (p<0.05). Serum apo B level was lower in hyperthyroidism than in overt hyperthyroidism, subclinical hypothyroidism and healthy control subjects (p<0.05).
CONCLUSION
Serum CRP and Lp(a), risk factors of atherosclerosis, were not significantly different according to thyroid dysfunction. Increased risk for atherosclerosis in overt hypothyroidism seems not to be associated with serum CRP level.