Is Thyroid Hormone a Risk Factor of Coronary Atherosclerosis in Korean Patients?

ABSTRACT

BACKGROUND AND OBJECTIVES: Overt and subclinical hypothyroidism is known to be associated with developing atherosclerosis and adverse changes in blood lipid. There has been no data regarding the effects of a normal range of thyroid hormone on the presence of coronary atherosclerosis. SUBJECTS AND METHODS: We studied 1 25 consecutive patients (age 60.0 +/-11.1 years, male female=8441) who underwent diagnostic coronary angiography. The clinical diagnoses on admission were stable angina (32.0%), unstable angina (53.6%), and acute myocardial infarction (14.4%). The thyroid hormones [thyroid stimulating hormone (TSH), free thyroxine and free 3 -iodothyronine], serum lipid levels, high sensitivity C-reactive protein (hsCRP) level, homocysteine and fibrinogen levels were measured. The coronary angiographic results were compared with laboratory findings. RESULTS: The angiographic diagnoses of coronary artery disease were no significant stenosis in 4 1 patients (32.8%), single vessel disease in 47 patients (37.6%) and multivessel disease in 37 patients (29.6%). The serum TSH levels showed a trend toward higher levels in the patients with multivessel disease compared to the patients with no significant stenosis (1.22+/-0.96 uIU/mL vs. 0.73+/-0.53 uIU/mL, respectively, p=0.053). According to the levels of TSH ( or =1.0 IU/mL), the incidence of multivessel disease was significantly higher in the patients with high serum TSH levels (23.1 % vs. 40.0%, respectively, p=0.038). A significant correlation was observed between the levels of TSH and the monocyte count (r=0.251, p=0.005), hsCRP level (r=0.208, p=0.023) and homocysteine level (r=0.279, p=0.002). CONCLUSION: The high level of serum TSH is associated with multivessel disease, abnormal inflammatory markers and high homocysteine levels.