Metformin in Postmenopausal Women With Metabolic Syndrome

Inclusion Criteria: * Postmenopausal women aged 45-60 years with metabolic syndrome according to The American Heart Association and The National Heart, Lung, and Blood Institute Exclusion Criteria: * Previous cardiovascular diseases * Contraindicated to metformin: serum creatinine \>1.4 mg/dL, liver disease, alcoholism, congestive heart failure, chronic hypoxic lung disease, prior history of lactic acidosis * Previous administration of metformin, other hypoglycemic drugs, lipid-lowering drugs, sex steroids, antiplatelet drugs within 3 months before enrollment * Fasting blood sugar ≥ 200 mg/dL or HbA1c \>8% * Serum triglyceride ≥500 mg/dL * Abnormal EKG