Beta Cell Restoration Through Fat Mitigation

BetaFat is a 2-arm, unblinded study to compare gastric banding to treatment with metformin over a 24-month period in moderately obese adults with pre- or mild type 2 diabetes. The primary outcome will be change in β-cell compensation for insulin resistance, which the investigators will compare between groups. Secondary analyses will include other potential markers of β-cell health and potential mediators of treatment-specific effects. The main focus will be on mediators related to obesity. Clinically, the project will serve as a test of concept for use of gastric banding relatively early in the spectrum of obesity and β-cell disease. Biologically, the results will provide crucial information on potential mediators of β-cell failure and its arrest or reversal in the context of obesity. Those mediators will guide the development of more effective treatment and monitoring for the β-cell disease that causes type 2 diabetes.

Inclusion criteria

• Prior completion of at least two months in a diet, exercise and lifestyle intervention program within the past two years
• Fasting plasma glucose >90 mg/dl plus 2-hour glucose ≥140 mg/dl on 75 gm OGTT plus HbA1C ≤7.0%. There is no lower limit for the A1C and no upper limit for the OGTT 2-hour glucose based on prior studies that allow us to identify people with falling β-cell function
• Age 22-65 years
• Body mass index (BMI) 30-40 kg/m2
• For participants with diabetes, known duration <1 year
• No history of use of antidiabetic medications except during pregnancy

Exclusion criteria

• Contraindications to LapBand(see Appendix 1)
• Contraindication to MRI (claustrophobia; permanent metal objects such as pacemakers, prostheses, aneurysm clips)
• Underlying disease(s) likely to (a) limit life span to less than study duration and/or (b) increase risk of intervention outside of the study and/or (c) limit ability to participate in outcomes assessment and/or (d) limit participation
• An underlying disease known to have important effects on glucose metabolism
• Active infections
• Renal disease (serum creatinine ≥1.4 mg/dl for men; ≥1.3 mg/dl for women) or serum potassium abnormality (<3.4 or >5.5 mmol/l)
• Anemia (hemoglobin <11g/dl in women, <12 g/dl in men) or known coagulopathy
• Cardiovascular disease, including uncontrolled hypertension and symptomatic congestive heart failure. Participants must be able to safely tolerate administration of fluid/volume challenges during clamp studies.
• Serum AST >3 times upper limit of normal in local clinical lab
• Excessive alcohol intake
• Suboptimally treated thyroid disease
• Conditions or behaviors likely to affect the conduct of the study

• unable or unwilling to give informed consent
• unable to adequately communicate with clinic staff
• another household member is a participant or staff member
• current or anticipated participation in another intervention research project that would interfere with any of the interventions/outcomes
• likely to move away from participating clinic in next 2 years
• current (or anticipated) pregnancy and lactation.
• major psychiatric disorder that, in the opinion of clinic staff, would impede the conduct of the study
• weight loss >5% in past three months for any reason except postpartum weight loss.
• additional conditions may serve as criteria for exclusion at the discretion of the local site