What causes most cases of type 1 diabetes?
It is thought that there are several reasons for the development of type 1 diabetes, but most of them are debated or still need to be studied. The most commonly mentioned one involves the body’s own immune system attacking beta cells in the pancreas, causing the organ to stop producing insulin. The development of the disease is thought to be part genetic, but scientists (to date) agree that no one characteristic seems to bring about type 1 diabetes.
How long does it take for type 1 diabetes to develop?
There is no real set “schedule” for a person to eventually develop type 1 diabetes. According to research and statistics, the body’s autoimmune system can attack a person’s beta cells over months or even years, eventually resulting in type 1 diabetes.
What are some of the definitions of “type 1.5 diabetes”?
The term “type 1.5 diabetes” has been used to describe several different types of conditions. In some research, it is also called LADA, or latent autoimmune diabetes in adults. Type 1.5 diabetes has also been used to describe the condition of a person who has both type 1 and 2 diabetic features. In particular, the body not only fails to make its own insulin but also resists injected insulin (it has also been called “double diabetes”).
Do only young children develop type 1 diabetes?
No, it is a misconception that only children develop type 1 diabetes. Although the majority of type 1 diabetics are children—which is why so many people erroneously believe any adult-onset diabetes must be type 2—an adult can develop a slow-onset form of type 1 diabetes called latent autoimmune diabetes in adults (or LADA; for more about LADA, see above).
Can exposure to chemicals or drugs cause type 1 diabetes?
A few studies suggest that there may be a connection between type 1 diabetes and exposure to chemicals or drugs. But it is unlikely that such an environmental factor (such as exposure to a chemical or drug) alone can cause diabetes. It may be that if a person with a genetic susceptibility (inheriting a particular set of genes) is exposed to a certain chemical or environmental “triggering” factor, he or she may develop type 1 diabetes. But overall, this concept is highly debated.
What are the chances of developing type 1 diabetes because someone in the person’s family has the disease?
According to several studies, including one from the Joslin Diabetes Center, if a father has type 1 diabetes, the child has a 7 percent chance of developing the disease; if the mother has type 1 diabetes, the child has a 2 percent chance of developing type 1 diabetes. Other research suggests that the risk for developing type 1 diabetes is between 1 and 10 percent for people with a parent or sibling with the disease. Overall, the average chance of a child’s developing type 1 diabetes is 0.3 to 0.4 percent.
Why does heredity play a part in type 1 diabetes?
Although the genetic component of type 1 diabetes is not as strong as for type 2 diabetes, there is a reason for the higher risk of the disease being passed from generation to generation. Research has shown that DNA, or deoxyribonucleic acid—the set of instructions that tells the cells in the body how to grow, live, and function—mutates, increasing the risk for the disease.
What are antibodies and autoantibodies?
Certain white blood cells of a person’s immune system are mainly responsible for protecting the body from germs and foreign invaders, including T cells (they attack foreign cells directly) and B cells (they produce antibodies, or special proteins that can recognize the surface shapes of molecules that attack the body).
Autoantibodies—usually found in people with autoimmune disorders—are B cells that sometimes make their own antibodies and recognize a person’s own cells. In the case of type 1 diabetes, it is thought that the autoantibodies identify the insulin-producing cells of the pancreas (beta cells) as cells to be attacked, and from there, the T cells destroy the beta cells.
What autoantibodies are common in people with type 1 diabetes?
There appear to be three autoantibodies that are common in people with type 1 diabetes. In the pancreas, these autoantibodies recognize and attack the islet cells (of which beta cells are one type), insulin, and glutamic acid decarboxylase (a protein made by the beta cells in the pancreas, also called GAD or the 64 K protein). The autoantibodies seem to be markers in the body and contribute to the destruction of the pancreas’ beta cells by identifying which cells should be attacked by the immune system. Ultimately, this causes the immune system’s T cells to destroy the insulin-producing cells of the pancreas.
Overall, of the people who are newly diagnosed with type 1 diabetes, 70 to 80 percent have autoantibodies to islet cells, 30 to 50 percent have autoantibodies to insulin, and 80 to 95 percent have autoantibodies to GAD. These autoantibodies often appear before the symptoms of type 1 diabetes show up. Thus, some researchers suggest that people who are at higher risk of developing type 1 diabetes be screened for these autoantibodies.
Can a virus cause type 1 diabetes?
Through the many years of research on type 1 diabetes, several reports have suggested that the disease may be caused by a virus. To date, no such virus—or even indirect evidence of such a virus—exists. Here are several of the viral-diabetes connection suggestions:
- One suggestion is that people who develop type 1 diabetes, according to some reports, often have had a recent viral infection before they are diagnosed. It has also been reported that many diagnoses of type 1 diabetes occur after a major viral outbreak.
- Another suggestion comes from research suggesting that viruses that cause mumps and German measles, along with the Coxsackie family of viruses (related to the virus that causes polio), may play a role in the development of type 1 diabetes. The researchers note that a certain autoantibody (see above) is almost identical to a region of a protein found in the virus Coxsackie B4. And because both are similar, the immune system’s T cells may not be able to tell the difference, thus destroying the “invading” cell, but in reality destroying the body’s own beta cells.
- Still another virus suggestion is that type 1 diabetes is a relatively new disease caused by a slow-acting virus, causing the immune system to attack proteins in the pancreas. To date, no such virus has been found.