Cardiovascular Effects of Metformin on Obesity

Inclusion Criteria:

• Adolescents 12 to 17 years old under clinical care at the UCSF WATCH clinic
• Body mass index> 95th percentile for age and gender according to the Centers for Disease Control and Prevention 2000 growth charts for the United States
• Insulin resistant after 6 months of healthy diet and exercise
• Able to understand the assent form

Exclusion Criteria:

• Patients with known cardiac disease

• Patients with contraindications to metformin as listed below:

  • Renal disease or renal (serum creatinine levels ≥1.5 mg/dL for males, and ≥1.4 mg/dL for females;
  • Known hypersensitivity to Metformin;
  • Acute or chronic metabolic acidosis;

• Patients with contraindications to MRI including:

  • Cardiac pacemaker;
  • Claustrophobia;
  • Metallic foreign body in the eye,
  • Aneurysm clip in the brain
• Pregnancy;
• Patients who could not stay still for 30 minutes within the MRI scanner due to other reasons besides claustrophobia