We know that Type 1 diabetes is not contagious like a cold. Three factors seem to be important in determining why a person develops Type 1 diabetes:
Although 90 percent of people who develop Type 1 diabetes have no close relative with the condition, there is still a strong genetic component. Most people with Type 1 diabetes inherit an HLA DR3 or DR4 gene from each parent, which makes them at high risk to develop diabetes. A person with a close family member with diabetes has about a 10 percent (1 in 10) chance of developing diabetes (compared to a 1 percent chance in the general population). When one identical twin develops Type 1 diabetes, the second twin has a 66 percent chance of also developing the disease.
The second cause that seems to be important in Type 1 diabetes is self-allergy (or autoimmunity). Normally, our immune system protects our bodies from disease. In the case of Type 1 diabetes and other autoimmune diseases, such as lupus, arthritis and multiple sclerosis, the immune system turns against a body part. The immune system treats that body part like an allergen and damages it. The allergic (autoimmune) reaction in Type 1 diabetes is against the islet cells in the pancreas, which make insulin. Islet cell autoantibodies (ICA) may be present in the blood for many years before insulin is required.
Because the genetic predisposition for autoimmunity is present in people with Type 1 diabetes, other autoimmune conditions are more apt to be present. From 3 to 5 percent of people develop celiac disease, an allergic reaction to the protein gluten. Gluten is found in wheat, rye and barley and must be excluded from the diet. Approximately 10 percent of people with Type 1 diabetes eventually develop thyroid autoimmunity requiring treatment. Autoimmune adrenal disorders are rare, but also occur.
This environmental factor is most likely a virus, but could also be something in the food we eat or something we do not yet know about. This factor may be the bridge between the genetic (inherited) susceptibility and the allergic reaction.
The incidence of new cases of Type 1 diabetes is increasing worldwide at 3 to 5 percent per year (doubling in 10 years). It is unknown why this is happening, but it may be secondary to a causative agent in the environment or to the loss of protective agents.
A recent scientific report found that eating high amounts of sugar did not lead to a greater likelihood of the self-allergy. However, once the self-allergy (positive islet cell antibodies) was present, eating higher amounts of sugar led to a more rapid onset of diabetes.
The prevention of Type 1 diabetes is being studied in a large program called Type 1 Diabetes/TrialNet (diabetestrialnet.org). Healthy relatives of people with Type 1 diabetes are screened for the islet cell antibodies in their blood. If the antibodies are present, individuals may be eligible to enter a prevention study. Five medications have been found that delay the onset of diabetes, but none that prevent it completely. If you are interested in participating in the free study, call 1-800-425-8361 for more information.