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Diabetes type 1

Overview

Type 1 diabetes mellitus is an illness where the insulin producing cells of the pancreas are destroyed by an autoimmune process which results in complete lack of insulin and therefore high blood sugars.  The prevalence in the United States is 0.5% of the population which is 1 in 400 children or 1 of 200 adults. 

Causes

Antibodies are proteins in the body that fight infections normally. Sometimes they attack the own body's organs and this is called an autoimmune disease. The autoimmune process that selectively destroys pancreatic beta cells is T-cell mediated with an unknown cause. There seem to be environmental factors including rubella and coxsackie viruses. There are dietary factors such as early exposure to cow's milk. The antibodies to pancreatic beta cells (GAD65, IA-2, and IAA) can be found in the blood of most patients before diagnosis and for a while after the onset of high blood sugars. GAD65 is positive in 80% of children and adults near the time of diagnosis. IA-2 and IAA are present in about 50% of the cases. The presence of two of the antibodies highly predicts the need for long term insulin dependency.  

Patients with diabetes type 1 are at increased risk for other autoimmune diseases such as Hashimoto's thyroiditis, Graves' disease, Addison's disease, pernicious anemia, celiac sprue, vitiligo, alopecia, and chronic active hepatitis. These risks increase with advancing age so periodic screening should be done throughout adulthood. 

The genetics of type 1 diabetes are not clear.  In a family of a patient with type 1 diabetes, the risk of an identical twin developing type 1 diabetes is 30%,  an offspring is 5%, and a sibling is 5%.  These low risks strongly suggest that environmental causes place a heavy part. 

Complications

Patients with type 1 diabetes and type 2 diabetes mellitus are at risk for the same long-term-complications and short-term-complications.  Although the complications for both types of diabetes are the same, they may not appear at the same times or with the same severity. The reasons for these complications are related to increased oxidative stress and the toxicity of advanced glycation end products which are formed by the process of glycation of lipids and proteins. Glycation is the process by which a substance in the body is coated with sugar, so basically molecules in the body are sugar-coated and become damaged by that process.  


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