Relationship between fibroblast growth factor 21 and thyroid stimulating hormone in healthy subjects without components of metabolic syndrome

Objective:To determine the relationship between human fibroblast growth factor 21(FGF21)and thyroid stimulating hormone(TSH)by testing the level of FGF21,lipid metabolism,and car-bohydrate metabolism-related indices,as well as the level of TSH,among metabolic syndrome-free patients with normal physical examination results.Methods:An enzyme-linked immunosorbent assay(ELISA)was used to test the levels of serum FGF21 and free fatty acids(FFA)in metabolic syndrome-free patients with normal physi-cal examination results,and electrochemiluminescence(ECLIA)was used to measure TSH,thy-roglobulin antibodies(TGAbs),and thyroid peroxidase antibody(TPOAb)levels.Results:Three hundred fifty-six metabolic syndrome-free patients(116 males and 240 females;average age,43±13 years)with normal physical examination results were enrolled.Among the pa-tients with normal physical examination results,FGF21 had a weak relationship with obesity indices,such as the waist circumference(r=0.110,P=0.038),the waist-to-hip ratio(r=0.119,P=0.025),and the triglycerides level(TG;r=0.302,P=0.000),and a weak relationship with blood lipid levels,such as total cholesterol(TCHO;r=0.113,P=0.012)and low-density lipoprotein-cholesterol(LDL-C;r=0.175,P=0.001),but no relationship with TSH(r=-0.023,P=0.666).In addition,the FGF21 levels in thyroid autoantibody-positive and-negative groups were not significantly different.Conclusion:Among the metabolic syndrome-free patients with normal physical examina-tion results,FGF21 has no apparent relationship with TSH or thyroid autoimmunity.