Are Serum Thyrotropin level and Subclinical Hypothyroidism Predisposing Factors for Coronary Artery Disease?

vert hypothyroidism has been found to be associated with cardiovascular diseases. Whether or not subclinical hypothyroidism is also a risk factor for cardiovascular disease is controversial. The aim of this study was to investigate serum thyrotropin levels and subclinical hypothyroidism in relation to presence and extent of coronary artery disease (CAD). Materials and Methods: In a sample of 390 persons (239 men and 151 women) with mean age of 55.12±10.52 years who had referred for coronary angiography, data on general health, thyroid status, medications and previous myocardial infarction were obtained at baseline. They were screened for impaired thyroid function using a sensitive immunoradiometric assay for thyrotropin. Subclinical hypothyroidism was defined as an elevated serum thyrotropin level (≥ 4. 0mU/L) and a normal serum free thyroxine level. A single-, two- or triple vessel disease or normal vessels was documented by coronary angiography. Results: Subclinical hypothyroidism was present in 6.4% of persons and was not associated with a higher frequency (P=0.51) or greater severity (x2=2.172; P=0.70) of CAD. The mean serum thyrotropin level was significantly higher in women (P<0.001). There was neither correlation between serum thyrotropin level and the presence of CAD (P=0.37) in either sex (men: P=0.67 /women: P=0.97) nor with the extent of CAD (P=0.30) in either of the two groups (men: P=0.70 /women: P=0.34). Also, serum thyrotropin level was not higher significantly in patients who had has previous myocardial infarction (P=0.95). Conclusions: There was no correlation between thyrotropin levels or subclinical hypothyroidism and presence or severity of CAD in a cohort of patients who referred for coronary angiography.