T1D develops as a result of the destruction of the beta-cells of the pancreas. It is characterized by absolute insulin deficiency, and may be fatal if not treated with lifelong insulin therapy. Severe complications at onset of T1D include hyperglycemia, ketoacidosis and even death. At present, approximately 20 million people worldwide, mostly children and adults, have T1D.

In the past, T1D has also been called juvenile onset diabetes (JOD) because it is seen most often in children and young adults. It was also referred to as insulin-dependent diabetes mellitus (IDDM) because of the absolute requirement for life long insulin therapy. Today, it is called type 1 diabetes (T1D).

At the present time, two forms of T1D are recognized. Type 1A is the more common form of the disease. It is immune mediated and characterized by the presence of autoantibodies to beta cell proteins, known as antigens. Type 1B is very rare and is considered to be idiopathic because it may be a secondary complication of conditions like cystic fibrosis, or it may be induced by particular environmental toxins. When the term T1D is used in this Module, we are referring to Type 1A.

Treatment for T1D requires a strict regimen that is designed to maintain near normal levels of blood glucose. This typically includes multiple daily insulin injections, a carefully calculated diet, planned physical activity, and blood glucose testing several times a day. Individuals with good glycemic control are less likely to develop some of the serious long-term complications of the disease, which include cardiovascular, peripheral vascular, ocular, neurologic and renal abnormalities.