Causes of Diabetes
Type 1 Diabetes is an autoimmune disease and occurs relatively infrequently. The body’s own immune system attacks the pancreatic beta cells that produce insulin, thereby creating a total deficiency in insulin production. About 80-90% of type 1 diabetics have autoantibodies (markers of auto immune destruction of the pancreas) in their blood stream.
- Type 1 diabetes may run in families via genetic inheritance. Greater than 20 different regions on the human genome are thought to be linked to diabetes.
- Environmental factors play a role in triggering the immune system to attack the pancreas. While environmental factors are believed to trigger the attack, the exact factors (e.g. toxins, viruses, etc.) are not known.
- Viral infections such as coxsackie, cytomegalovirus, mumps, Epstein-Barr, etc may affect the onset of diabetes.
- Insulitis is the infiltration of islet cells in the pancreas by activated immune cells as a response to infections.
- Diet and stress also have been implicated in diabetes.
Type 2 Diabetes is most commonly occurring form of diabetes (roughly 90% of diabetics). Unlike type 1 diabetics, type 2 diabetics still produce the hormone insulin, but their pancreas produces too little and their bodies are unable to utilize the insulin in a normal fashion (insulin resistance). Type 2 diabetes used to be called adult-onset diabetes since it typically affected individuals over 40, but in recent years, it has been diagnosed in younger individuals at an epidemic level. Type 2 diabetes is less well understood than type 1 diabetes. It is thought that a combination of many factors lead to the disease.
- Type 2 diabetes often occurs in people that are obese. Roughly 90% of type 2 diabetics are obese. All overweight individuals are insulin resistant in varying degrees, but it is the inability to increase pancreatic beta cell production that triggers the development of diabetes.
- Genetics play a greater role in type 2 diabetes than type 1. Several genes are thought to be involved (polygenic model), but the exact mechanism of inheritance and the identity of specific genetic factors leading to the disease are not known.
- Bad diet (high fat), high blood pressure, and high alcohol consumption all play a major role in type 2 diabetes.
- Age is also an important risk factor. The risk of type 2 diabetes increases slightly after age 50 and increases significantly after age 65.
- Certain ethnic groups have a greater risk for type 2 diabetes. For instance, African Americans, Hispanic Americans and Native Americans are more susceptible to type 2 diabetes than Caucasian Americans.
- Insulin resistance can take place due to the following causes: a) target tissue defect, b) defective insulin molecule or c) excess circulating insulin antagonists. Target tissue defect is the most common cause. There are multiple biochemical mechanisms that account for this tissue impairment.