Patients displaying overt and subclinical hypothyroidism have more cardiovascular risk factors. Consequently, they are more likely to develop atherosclerosis and cardiovascular diseases.
Objective
To analyze whether low free-thyroxine levels (FTL) would also be associated with atherosclerosis in euthyroid patients.
Methods
We selected a group of 1434 healthy euthyroid male patients without known histories of thyroid disease and with levels of thyroid-stimulating hormone values within the normal range (mean 1.70 ± 0.76 mUl/l, range 0.13–4.01 mUl/l). Mean age of these patients who had been referred for assessment of hyperlipidemia was 44.6 years and mean FTL was 14.25 ± 3.06 pmol/l. We divided the population according to the degree of atherosclerosis in the carotid arteries.
Results
Mean age, body mass index, systolic blood pressure, cigarettes/day, blood level of glucose, cholesterol levels, and fibrinogen levels were significantly higher for the patients with atherosclerotic lesions whereas mean FTL was lower for patients with carotid atherosclerosis (P = 0.0002). The relationship between FTL and carotid atherosclerosis was independent from the following cardiovascular risk factors: age, hypertension, amount of excess weight, cholesterol level, fibrinogen level, smoking status, and presence versus absence of diabetes mellitus.
Conclusions
Low FTL is a risk factor for atherosclerosis in male euthyroid hyperlipidemic patients.
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