Abstract P139: Ft3 Level Correlates with Arterial Stiffness and Systolic Blood Pressure: A Cross-sectional Study

Background: Previous studies have suggested that thyroid dysfunction was associated with numerous risk factors of cardiovascular diseases, but whether thyroid function status could influence arterial stiffness and blood pressure (BP) has not been investigated sufficiently. Methods: From January to December 2011, we enrolled 1732 patients who took physical examination in our center consecutively. The exclusion criteria were: previous histories of cardiovascular and cerebrovascular diseases, current usage of any anti-hypertensive drugs, anti-thyroid drugs, or thyroxin. All patients underwent testing for thyroid function status, brachial-ankle pulse wave velocity (baPWV), and ankle brachial index (ABI). We investigated the relationship between thyroid hormone levels, arterial stiffness markers (baPWV and ABI) and BP. Results: There were 97 patients (5.6%) who had thyroid dysfunction, including low-T3-syndrome (11 patients, 0.64%), subclinical hypothyroidism (51 patients, 2.94%) and clinical hypothyroidism (19 patients, 1.10%), subclinical hyperthyroidism (16 patients, 0.92%). After adjusting for conventional risk factors (age, gender, smoking, diabetes mellitus, dyslipidemia, previous hypertension), free triiodothyronine (FT3) was negatively correlated with baPWV (r=-0.482, P<0.001) and positively correlated with ABI (r=0.290, P<0.001), indicating that the lower FT3 level correlates with arterial stiffening. FT3 also had a moderate negative correlation with systolic BP (r=-0.375, P<0.001). TSH was significantly associated with baPWV (r=0.327, P=0.002), but it did not have any relationship with ABI and BP. No significant correlation was found between other thyroid hormone levels (TT4, FT4 and TT3), baPWV, ABI and BP. Conclusions: Lower FT3 and higher TSH were associated with arterial stiffening markers. In addition, FT3 is negatively correlated with systolic BP. These results indicate that thyroid hormone levels play an important role in arterial stiffness and hypertension. Further study is warranted to investigate whether thyroid hormone therapy could benefit people with arterial stiffening and hypertension.