Obesity and type 2 diabetes are tightly coupled. Excess ectopic fat in the body is the major cause of insulin resistance and fat also damages the beta cell. It is therefore unusual to see a thin Type 2 diabetic. In fact the author teaches medical students to “beware the thin type 2 diabetic”. The point is that a careful search for other pathologies may be required.
The question to ask is why does this individual have beta cell failure?
1. Is it due to an immune attack (positivity for anti GAD antibodies) if so this is Latent Autoimmune Diabetes of Adults (LADA).
2. Is it due to pancreatic failure (chronic pancreatitis or pancreatic cancer)
3. Is it due to toxic damage to the beta cell (haemochromatosis)
4. Is it due to genetic susceptibility to beta cell failure with modest insult (Non European ethnicity)
To develop diabetes, it is essential to have beta cell failure. There are many mechanisms known that can damage these cells including nutrient toxicity, cytokine attack and hyper-stimulation. Some mechanisms will be discussed.