- Non-diabetic adults aged between 40 and 64 years fulfilling the American Heart Association/National Heart, Lung and Blood Institute diagnostic criteria of metabolic syndrome (at least 3 of the following: waist circumference ≥102 cm (males) or ≥88 cm (females); fasting triglycerides≥150 mg/dL or on drug therapy for decreasing triglycerides; fasting HDL-cholesterol ˂40 mg/dL (males) or ˂50 mg/dL (females) or on drug therapy for increase HDL-c; systolic blood pressure ≥130 mmHg or diastolic blood pressure ≥85 mmHg or on antihypertensive drug therapy; fasting glycemia≥100 mg/dL