Tests for Type 1 Diabetes
If your doctor suspects diabetes, he or she will perform a blood test, such as the A1C, fasting plasma glucose test, or the random plasma glucose test. These tests are discussed in more detail in chapter 2. If a fasting plasma glucose test is 126 mg/dl or higher or the random plasma glucose test is 200 mg/dl or higher, you may be diagnosed with diabetes.
Your own description of the way your diabetes symptoms developed will help your health care provider classify your diabetes as type 1.
Your health care provider may also take a urine sample to check for the presence of ketones. Ketones are byproducts produced by the body when it breaks down fat for energy. The presence of ketones could be a clue that you have type 1 diabetes. However, keep in mind that ketones are also common in people with type 2 diabetes who are under stress or who have a medical emergency.
In addition, once diabetes has been diagnosed, your health care provider may take a blood sample to test for the presence of autoantibodies in your blood (see more about autoantibodies in the next section). The presence of autoantibodies could mean you have type 1 diabetes. However, some people with type 1 diabetes do not have autoantibodies.
Another measurement, called the “C-peptide” test, measures the amount of insulin produced by the body. It may be ordered if you’ve just been diagnosed with diabetes and is sometimes ordered in conjunction with a diagnosis of type 1 diabetes.
Causes and Risk Factors
Scientists do not know the exact cause of type 1 diabetes. They suspect that it is a combination of factors due to a person’s genetics and environment.
However, scientists do know that in people with type 1 diabetes, their immune system mistakenly destroys the insulin-producing cells of their pancreas. The destruction can happen over months and years. The body treats these insulin-producing cells as foreign invaders (not good!). This is called an autoimmune response.
Autoantibodies
In fact, the body creates specific proteins called autoantibodies. When certain autoantibodies are present, they indicate an autoimmune response is helping to kill cells in the pancreas.
Four antibodies are particularly common in people with type 1 diabetes: islet cell autoantibodies, insulin autoantibodies, glutamic acid decarboxylase autoantibodies, and tyrosine phosphatase autoantibodies. Doctors often test for the presence of these autoantibodies to determine whether someone has type 1 diabetes.
Autoimmune responses can occur in other diseases, such as multiple sclerosis and lupus. In fact, people with other autoimmune disease, such as thyroid disease and celiac disease, are more likely to have type 1 diabetes.
Scientists do not know what causes autoimmune diseases. However, in diabetes, researchers have found a few triggers that may point to why the body starts attacking itself.
Celiac Disease
One in 20 people with type 1 diabetes has celiac disease.
Genes and Family History
Scientists have long suspected that family history and genes play a role in type 1 diabetes. For example, if your parent or sibling has diabetes, you are more likely to develop the disease than someone without a family history.
The way in which genes interact to cause diabetes is an extremely complex process that scientists are only just beginning to unravel. Some of the most promising discoveries have been made with a group of genes called HLA that are involved in the body’s immune response. Scientists can test a person’s DNA for specific mutations in HLA genes that would indicate that that person might get type 1 diabetes.
Race and Ethnicity
In addition to family history, race and ethnicity appear to play a role in who develops type 1 diabetes. White people are much more likely to develop type 1 diabetes than other racial groups. For example, 1 in 100,000 people in Shanghai, China, has type 1 diabetes, but more than 35 in 100,000 people in Finland have type 1 diabetes. Most likely, certain racial groups pass down genes that either trigger or protect against type 1 diabetes.
Viruses
Many scientists suspect that viruses may cause type 1 diabetes. Some people who develop diabetes have often had a recent viral infection. Also, cases of diabetes have frequently occurred after viral epidemics. Viruses—such as those that cause mumps, German measles, and a virus related to the one that causes polio—may play some role in causing type 1 diabetes. Nonetheless, there is no virus known that specifically triggers type 1 diabetes.
Chemicals and Drugs
Several chemicals, in rare cases, have been shown to trigger diabetes. Pyriminil, a poison used to kill rats, can trigger type 1 diabetes. Two prescription drugs, pentamidine (used to treat pneumonia) and L-asparaginase (an anticancer drug) can also cause type 1 diabetes.
Prevention
There is no way to prevent type 1 diabetes. However, scientists are deeply interested in finding ways to delay or reduce the severity of type 1 diabetes.
People without outward symptoms of type 1 diabetes often produce autoantibodies that can be detected in the blood. The autoantibodies may be present several years before diabetes is diagnosed. Currently, scientists can screen people who may be at high risk because they have a family member with type 1 diabetes or because they carry mutations in certain HLA genes.
For example, if you have a parent or sibling with type 1 diabetes, you are 10% more likely to get diabetes. However, if you also carry certain HLA genes or autoantibodies in your blood, you are even more likely to get type 1 diabetes.
Several studies currently underway are testing whether treating these people early may improve their lives. One study is treating people with insulin in a pill form, and other studies are examining whether certain diets could affect the development of type 1 diabetes. Still other studies are aimed at vaccines to slow the progression of diabetes after diagnosis.
In summary, it is unlikely that either genetics or environment alone causes diabetes. Instead, it is probably a complicated interplay between the genes you were born with and the world in which you live.
Management and Treatments
How you manage your diabetes depends on your personal goals and needs. No two people with diabetes are exactly alike. Therefore, everyone with diabetes needs an individualized diabetes care plan.
Common Goals for People with Diabetes
• Prevent short-term problems, such as a glucose level that is too low or too high.
• Prevent or delay long-term health problems, such as heart disease and damage to the nerves, kidneys, and eyes.
• Maintain a healthy lifestyle and keep doing enjoyable activities, such as exercising, working, and socializing.
Work with your health care providers to come up with a plan for managing your diabetes and meeting your goals. You’ll find more about this topic in chapter 9. For now, though, let’s talk about some of the treatments for managing type 1 diabetes.
• People with type 1 diabetes must take insulin. Therefore insulin injections play a big role in your diabetes care plan. How much insulin you need to take depends on your blood glucose level or what you predict the level will be after a meal.
• Naturally, certain food choices also play an important role in your diabetes management plan, because they can add