Ailments and Situations - Diabetes - Type 2 Diabetes Mellitus

Type 2 Diabetes Mellitus / Non-Insulin-Dependent Diabetes Mellitus (NIDDM)

The second type of diabetes is called type 2 diabetes mellitus or non-insulin-dependent diabetes mellitus (NIDDM). The latter name is somewhat misleading because up to 25% of people with this form of DM require insulin. It is the most common form of diabetes; 90-95% of all diabetics have type 2. These diabetics have some effective insulin with an absence of ketosis. Eighty to ninety percent of these individuals are overweight. It usually present in adults 40 years of age and older. When it occurs in the young it is often called maturity-onset diabetes of youth (MODY). Obesity, advancing age, and a high fat diet are risk factors. Type 2 diabetes is a major health problem associated with high morbidity and mortality, and high health care cost.

The symptoms of NIDDM usually develop gradually, and are not as noticeable as those of Type 1 DM. Symptoms include excessive urination (polyuria), unusual thirst, weight loss, blurred vision, frequent infections, slow healing of sores, glycosuria, hyperglycemia, and excessive hunger. These diabetics often feel tired, ill, or weak, and their urine is usually pale due to the large amount of water excreted.

At first, there is normal insulin output from the pancreas. However, the cells of the body are said to be insulin resistant. This can occur because of intrinsic defects in insulin receptors on the cell surface, such that insulin cannot bind to them and get glucose into the cell. It can also be due to anti-insulin antibodies, which render the insulin unusable, or due to accelerated rates of breakdown of the insulin molecule. Regardless of the reason, the insulin resistance results in ineffective use of insulin. The result is a condition of impaired glucose tolerance (IGT) and hyperglycemia. IGT increases the risk of developing NIDDM and cardiovascular disease. The prevalence of IGT in adults is 11 to 20 percent in North America (incidentally, that number is 3 to 10 percent in Europe). A large number of people with IGT go on to develop NIDDM via the following process. The pancreas produces more insulin to make up for the high blood glucose levels. This can cause a decrease in the number of receptors that are expressed on cell surfaces (down-regulation) and hyperinsulinemia results. The b-cells become exhausted in the effort and diabetes results.