FGF21 and type 2 diabetes mellitus: Time-to-event analysis showed that there was a significant association between FGF21 and T2D (HR per doubling: 1.26 [95% CI 1.06–1.51]) in participants without impaired fasting glucose instead of those who had impaired fasting glucose, which indicated that FGF21 was an early biomarker of T2D before the development of impaired fasting glucose [27].