also have impaired glucose tolerance, a condition in which blood plasma glucose levels are higher than normal (140 mg/dl to 199 mg/dl) 2 hours after the start of an oral glucose tolerance test. If your A1C is 5.7–6.4%, you may be at similar risk.
If you have impaired fasting glucose and/or impaired glucose tolerance, you may be diagnosed with prediabetes. This is not the same as having diabetes, but it sometimes occurs before diabetes develops.
If you have been diagnosed with prediabetes, you will want to have your blood glucose tested routinely and watch for symptoms of diabetes. Also, you need to talk with your health care provider about reducing your risk of heart disease. Keeping your weight in the healthy range and exercising regularly will lower your chances of developing diabetes.
Prediabetes
Some people with prediabetes never get diabetes, especially if they make lifestyle changes that help improve their health, such as exercising more, making healthier food choices, and losing some unwanted weight. However, some of the same problems that result from having diabetes also occur in people with prediabetes.
Which Type of Diabetes?
If tests reveal that you have diabetes (and you’re not pregnant), the next question is whether you have type 1, type 2, or another type of diabetes. Although the symptoms and blood test results can be similar for both type 1 and type 2 diabetes, the causes are very different.
Part II
Types of Diabetes
CHAPTER 3
Type 1 Diabetes
Now, that you’ve brushed up on some of the basics of diabetes and glucose, you’re probably wondering about your specific type of diabetes. In this chapter, you’ll find out all about type 1 diabetes.
Type 1 diabetes used to be called juvenile diabetes. Half of all people with type 1 diabetes are diagnosed during childhood or their early teen years.
As you know, being diagnosed with diabetes can be a scary—no matter how old you are when you find out. However, being diagnosed with type 1 diabetes as a child can be downright terrifying. For example, it might have come on so fast that you went into a coma before anyone suspected diabetes. After asthma, type 1 diabetes is the second most common chronic disease in children.
Keep in mind, type 1 diabetes can occur at any age. About 5% of adults with diabetes have type 1 diabetes.
Early Symptoms and Tests
People with type 1 diabetes make very little or no insulin, which means that the symptoms of diabetes are often serious and swift. Without insulin, the cells in your body can’t do their essential work. Most people with type 1 diabetes will feel quite sick and may even be rushed to the hospital due to high blood glucose.
Common Symptoms of Type 1 Diabetes
• Frequent urination as the body tries to flush out excess glucose in the blood
• Extreme thirst due to dehydration
• Fatigue because the necessary glucose is not getting to your cells
• Blurred vision because of a buildup of fluid in your eyes or elevated glucose levels
• Weight loss, even with increased appetite
• Nausea and vomiting
A Different Type 1 Diabetes
Some people with type 1 diabetes may have a slow and relentless progression of symptoms. In fact, they may not need to start insulin right away. This condition is called latent autoimmune diabetes of the adult (LADA). As its name suggests, it occurs in adults. Scientists are still trying to clearly define the disorder to improve diagnosis and treatment of people with LADA.
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
