Overview of Diabetes Mellitus

What is diabetes mellitus?

Diabetes is a condition in which sufficient amounts of insulin are either not made, or the body is unable to use the insulin that is made. Diabetes can be defined as a metabolic disorder because the disease affects the way the body uses food to make glucose. This is the main source of fuel for the body. The three main types of diabetes include:

• Type 1 diabetes. Type 1 diabetes is an autoimmune disease in which the body's immune system attacks the cells that produce insulin. This results in either no insulin or a low amount of insulin. People with type 1 diabetes must take insulin daily in order to live.

• Type 2 diabetes. Type 2 diabetes is a result of the body's inability to make enough, or to properly use, insulin. Type 2 diabetes may be controlled with diet, exercise, and weight loss. It may also need oral or injected medicine and/or insulin injections.

• Gestational diabetes. Gestational diabetes is a condition in which the glucose level is elevated. Also, other diabetic symptoms appear during pregnancy when the woman has not previously been diagnosed with diabetes. In many cases of gestational diabetes, all diabetic symptoms disappear following delivery, but the woman is at risk for future diabetes.

What is prediabetes?

Type 2 diabetes is commonly preceded by prediabetes. In prediabetes, blood glucose levels are higher than normal but not high enough to be defined as diabetes. However, many people with prediabetes develop type 2 diabetes within 10 years, states the National Institute of Diabetes and Digestive and Kidney Diseases. Prediabetes also increases the risk of heart disease and stroke. With modest weight loss and moderate physical activity, people with prediabetes can delay or prevent type 2 diabetes.

How does diabetes affect blood glucose?

For glucose to be able to move into the cells of the body, the hormone insulin must be present. Insulin is made in the pancreas, and, normally, is readily available to move glucose into the cells. However, in people who have diabetes, either the pancreas makes too little or no insulin, or certain cells in the body do not respond to the insulin that is made. This causes a build up of glucose in the blood. This passes into the urine where it is eventually eliminated. The body is left without its main source of fuel.

What is maturity-onset diabetes in the young (MODY)?

Although often misdiagnosed initially as the more common type 1 or type 2 diabetes, maturity-onset diabetes of the young (MODY) is a group of diseases characterized by inherited early-onset diabetes (usually in adolescence or early adulthood) from a single gene mutation. 

Severity of the diabetes symptoms associated with MODY varies depending on the type of MODY diagnosed. MODY 2 appears to be the mildest form of the disease, often only causing mild hyperglycemia and impaired glucose tolerance. MODY 1 and 3 may need treatment with insulin, much like type 1 diabetes. MODY accounts for about 1% to 5% of all cases of diabetes in adults in the U.S. Family members of people with MODY are at greatly increased risk for the condition. MODY should be considered when three successive generations in a family have been diagnosed with mild diabetes (not requiring insulin) before age 25 and appear neither obese nor significantly insulin-resistant.