Carotid intima-media thickness as a marker of cardiovascular risk in patients with subclinical hypothyroidism

Subclinical hypothyroidism (SH) has been associated with an increased risk for coronary disease. Carotid intima-media thickness (IMT), as assessed by ultrasonography, is a precise marker of atherosclerotic changes and can be used as an endpoint for cardiovascular events. Aims of this study were to determine carotid IMT in a group of patients with SH and its possible association with an increase in cardiovascular risk. There were no significant differences in mean carotid IMT between patients and controls. Results of both groups were, respectively: common carotid arteries, 0.573 +/- 0.070 mm and 0.576 +/- 0.068 mm (p= 0.904); carotid bifurcation, 0.602 +/- 0.079 mm and 0.617 +/- 0.102 mm (p= 0.714). Similar results were obtained when analyzing subgroups with serum TSH < or > 8 mIU/L and with positive or negative titers of TPOAb. The mean carotid IMT in these subgroups were: TSH 4-8 mIU/L: 0.579 +/- 0.070 mm and 0.586 +/- 0.063 mm; TSH > 8 mIU/L: 0.569 +/- 0.073 mm and 0.616 +/- 0.091 mm; TPOAb+: 0.585 +/- 0.070 mm and 0.621 +/- 0.085 mm; TPOAb-: 0.554 +/- 0.072 mm and 0.571 +/- 0.066 mm. No differences in the lipid profile and in the apoprotein B and lipoprotein (a) levels between the groups were found. These findings suggest that mild SH with no related metabolic changes is not associated with an increase in cardiovascular risk, as assessed by carotid IMT.