Type 2 diabetes is a condition affecting slightly more than 7% of Americans. It used to be called adult-onset diabetes, but we now know it can occur in children as well as in adults. Another term for it was non-insulin-dependent diabetes mellitus (NIDDM), but about 30% of type 2 diabetics are treated with insulin.
Type 1 diabetes begins with death of insulin-producing beta cells in the pancreas. Typically this happens over a period of weeks or months and is not reversible. Type 2 diabetes may begin with a diminished production of insulin by the pancreas. Several risk alleles have been identified and have been found to have an additive effect, resulting in decreased glucose sensitivity in the pancreas of people who have not yet developed overt diabetes. This condition may go undetected for years, only becoming evident when the patient starts to experience insulin resistance. Often this happens during pregnancy, when the mother's body becomes less responsive to insulin during the third trimester. Gestational diabetes is a temporary condition, but can be an early indicator of a predisposition to type 2 diabetes. More often, as a person ages and becomes overweight, his or her muscles, liver and pancreas gradually develop increasing resistance to the action of insulin, and the symptoms of hyperglycemia start to appear. Insulin resistance in the liver may lead to overproduction of glucose by the liver, causing even more hyperglycemia. Hyperglycemia, in turn, may initiate a process called apoptosis (programmed cell death) in the pancreas, resulting in a pancreas that is significantly smaller and less able to produce insulin than the pancreas of a person who does not suffer from type 2 diabetes.
Unlike type 1 diabetes, the progression to type 2 diabetes usually occurs over several years. It does not typically result in the death of all the beta cells of the pancreas, but the ability of the pancreas to regulate blood glucose is significantly compromised. The presence of a genetic component is even more significant than it is in type 1 diabetes. In fact, if a person has a relative with type 2 diabetes, chances are 80% that the person will develop type 2 diabetes in his or her lifetime. With that in mind, it is a good idea to monitor fasting and postprandial glucose levels to see if blood sugars are starting to trend outside the normal range. If symptoms are detected early and the condition is managed appropriately, the progression to fullblown type 2 diabetes can be slowed or perhaps prevented altogether.
If you would like to do some more reading on the progression to type 2 diabetes, here are some links:
Reversing Insulin Resistance
(For those who are interested, the picture at the top is a Texas snowman.)