Association between Free Triiodothyronine Levels and Peripheral Arterial Disease in Euthyroid Participants

This current cross-sectional study investigates the relationship between thyroid hormones and peripheral artery disease (PAD) among euthyroid Chinese population aged 40 years and above. Serum free triiodothyronine (FT3), free thyroxin (FT4), thyroid-stimulating hormone (TSH), and thyroid antibodies were measured. PAD was defined as ankle-brachial index (ABI) < 0.9. There were 91 (2.9%) PAD cases among the 3,148 euthyroid study participants. Participants in the highest quartile of FT3 and free-triiodothyronine-to-free-thyroxin (FT3/FT4 ratio) had a decreased risk of prevalent PAD (multivariate-adjusted odds ratio, 95% confidence interval: 0.32, 0.15-0.62, P for trend = 0.01 and 0.31, 0.13-0.66, P for trend = 0.004, respectively) compared to those in the lowest quartile. To conclude, FT3 levels and the FT3/FT4 ratio was inversely associated with prevalent PAD in euthyroid Chinese population aged 40 years and above.