Objective
Fibroblast growth factor 21 (FGF21) plays regulatory roles in glucose and lipid metabolism. Thyroid dysfunction may affect body weight, energy expenditure, and glucose metabolism. We evaluated serum FGF21 levels in patients with hyperthyroidism or euthyroidism.
Subjects and methods
We recruited 30 newly-diagnosed hyperthyroid (HY) patients and treated them with anti-thyroid regimens as clinically indicated. Thirty euthyroid (EU) patients were recruited as controls. Laboratory parameters were measured at baseline and at 6 months. Associations between levels of FGF21 and free thyroxine (fT4), thyroid-stimulating hormone (TSH), log transformation of TSH (logTSH) or demographic, biochemical, and anthropometric data were analyzed.
Results
There were no significant difference of FGF21 levels among the HY and EU patients, both at baseline (p = 0.217) and at 6 months (p = 0.445). Serum FGF21 levels had no associations with levels of fT4, TSH, or logTSH, both at baseline and at 6 months. However, levels of FGF21 had positive associations with age, fasting plasma glucose (FPG) and triglyceride (TG) at baseline (β = 3.99, p = 0.005; β = 4.69, p = 0.008; and β = 0.90, p = 0.002, respectively) and at 6 months (β = 2.06, p = 0.020; β = 1.90, p = 0.007; and β = 0.49, p = 0.004, respectively).
Conclusions
Serum FGF21 levels are not associated with levels of fT4, TSH, or logTSH in patients with hyperthyroidism or euthyroidism. In this study, positive associations exist between levels of FGF21 and age, FPG or TG. Changes of serum FGF21 levels in the whole thyroid function spectrum remain to be investigated.