Background It is well known that various thyroid dysfunctions may affect the atherosclerosis. However, it was not established whether a normal range of thyroid stimulating hormone (TSH) influences the carotid intima-media thickness (IMT). We postulated that correlation between TSH and carotid IMT in patients with normal thyroid function.
Methods and Results We studied 226 consecutive patients with acute coronary syndrome (121 patients) or acute ischemic stroke (105 patients). TSH, free thyroxine, serum lipid levels and high-sensitivity C-reactive protein levels were measured and compared to the carotid IMT. In patients with high level of TSH (���2.2 關IU/mL), the levels of serum creatinine (p=0.048), the carotid IMT (p=0.030) were significantly higher than those in patients with low TSH levels. The levels of TSH were significant correlated with creatinine (r=0.161, p=0.017), fibrinogen (r=0.146, p=0.046), left carotid IMT (r=0.162, p=0.017), and right carotid IMT (r=0.138, p=0.042). Multiple linear regression analysis of all the subjects revealed that the independent factors of right carotid IMT were the levels of TSH (p=0.040) and homocysteine (p=0.003).
Conclusions The high level of serum TSH is correlated with increased carotid IMT even in patients with normal range of thyroid function.