FGF21 and metabolic syndrome: Serum FGF21 levels were also significantly elevated in subjects with metabolic syndrome (defined as having 3 or more of the following criteria: central obesity (waist circumference ≥ 80 cm in women and 90 cm in men), hypertriglyceridemia (fasting triglycerides ≥ 1/69 mmol/L), low HDL cholesterol (fasting HDL < 1.29 mmol/L in women and < 1.04 mmol/L in men), hyperglycemia (fasting glucose ≥ 5.6 mmol/L or taking oral hypoglycemic agents for the treatment of type 2 diabetes), or hypertension (sitting blood pressure ≥ 130/85 mmHg) (28).