Association between serum free thyroxine (FT4) and uric acid levels in populations without overt thyroid dysfunction.

In this study, we investigated the relationship between thyroid function and serum uric acid (UA) levels in subjects without overt thyroid dysfunction. A total of 6,085 patients were included in this cross-sectional study. Free thyroxine (FT4) levels were positively and linearly associated with serum UA levels (p<0.001), even after adjusting for age, thyroid-stimulating hormone, renal function, and other metabolic components (B 37.13; 95%CI 25.99-48.28; p<0.001). Furthermore, quartile analysis indicated that the prevalence of hyperuricemia was significantly elevated with increasing FT4 levels (quartile II: OR 1.232, 95%CI 1.022-1.486, p=0.029; quartile III: OR 1.234, 95%CI 1.025-1.486, p=0.026; quartile IV: OR 1.409, 95%CI 1.168-1.701, p<0.001). In summary, FT4 is linearly associated with serum UA levels in subjects lacking clinical thyroid dysfunction, and the prevalence of hyperuricemia is elevated with increasing FT4 levels.