12.4: Diabetes

Diabetes is a disease that occurs when your blood glucose, also called blood sugar, is too high. Blood glucose is your main source of energy and comes from the food you eat. Insulin, a hormone made by the pancreas, helps glucose from food get into your cells to be used for energy. Sometimes your body doesn’t make enough—or any—insulin or doesn’t use insulin well. Glucose then stays in your blood and doesn’t reach your cells. Over time, having too much glucose in your blood can cause health problems. The most common types of diabetes are type 1, type 2, and gestational diabetes.

Type 1 diabetes

If you have type 1 diabetes, your body does not make insulin. Your immune system attacks and destroys the cells in your pancreas that make insulin. Type 1 diabetes is usually diagnosed in children and young adults, although it can appear at any age. People with type 1 diabetes need to take insulin every day to stay alive.

Type 2 diabetes

If you have type 2 diabetes, your body does not make or use insulin well. You can develop type 2 diabetes at any age, even during childhood. However, this type of diabetes occurs most often in middle-aged and older people. Type 2 is the most common type of diabetes.

Gestational diabetes

Gestational diabetes develops in some women when they are pregnant. Most of the time, this type of diabetes goes away after the baby is born. However, if you’ve had gestational diabetes, you have a greater chance of developing type 2 diabetes later in life. Sometimes diabetes diagnosed during pregnancy is actually type 2 diabetes.

Other types of diabetes

Less common types include monogenic diabetes, which is an inherited form of diabetes, and cystic fibrosis-related diabetes.

How common is diabetes?

As of 2015, 30.3 million people in the United States, or 9.4 percent of the population, had diabetes. More than 1 in 4 of them didn’t know they had the disease. Diabetes affects 1 in 4 people over the age of 65. About 90-95 percent of cases in adults are type 2 diabetes.

Risk Factors for Type 2 Diabetes

Developing type 2 diabetes depends on a combination of risk factors such as genes and lifestyle. Although some risk factors are non-modifiable such as family history, age, or ethnicity, lifestyle risk factors around eating, physical activity, and weight are modifiable. These lifestyle changes can affect ones chances of developing type 2 diabetes. Read about risk factors for type 2 diabetes below and see which ones apply to you. You are more likely to develop type 2 diabetes if you

• are overweight or obese
• are age 45 or older
• have a family history of diabetes
• are African American, Alaska Native, American Indian, Asian American, Hispanic/Latino, Native Hawaiian, or Pacific Islander
• have high blood pressure
• have a low level of HDL (“good”) cholesterol, or a high level of triglycerides
• have a history of gestational diabetes or gave birth to a baby weighing 9 pounds or more
• are not physically active
• have a history of heart disease or stroke
• have depression
• have polycystic ovary syndrome, also called PCOS
• have acanthosis nigricans—dark, thick, and velvety skin around your neck or armpits

You can also take the Diabetes Risk Test to learn about your risk for type 2 diabetes.

What health problems can people with diabetes develop?

Over time, high blood glucose leads to problems such as

• heart disease
• stroke
• kidney disease
• eye problems
• dental disease
• nerve damage
• foot problems

Symptoms & Causes of Diabetes

Symptoms of diabetes include

• increased thirst and urination
• increased hunger
• fatigue
• blurred vision
• numbness or tingling in the feet or hands
• sores that do not heal
• unexplained weight loss

Symptoms of type 1 diabetes can start quickly, in a matter of weeks. Symptoms of type 2 diabetes often develop slowly—over the course of several years—and can be so mild that you might not even notice them. Many people with type 2 diabetes have no symptoms. Some people do not find out they have the disease until they have diabetes-related health problems, such as blurred vision or heart trouble.

What causes type 1 diabetes?

Type 1 diabetes occurs when your immune system, the body’s system for fighting infection, attacks and destroys the insulin-producing beta cells of the pancreas. Scientists think type 1 diabetes is caused by genes and environmental factors, such as viruses, that might trigger the disease. Studies such as TrialNet are working to pinpoint causes of type 1 diabetes and possible ways to prevent or slow the disease.

What causes type 2 diabetes?

Type 2 diabetes—the most common form of diabetes—is caused by several factors, including lifestyle factors and genes.

Overweight, obesity, and physical inactivity

You are more likely to develop type 2 diabetes if you are not physically active and are overweight or obese. Extra weight sometimes causes insulin resistance and is common in people with type 2 diabetes. The location of body fat also makes a difference. Extra belly fat is linked to insulin resistance, type 2 diabetes, and heart and blood vessel disease.

Insulin resistance

Type 2 diabetes usually begins with insulin resistance, a condition in which muscle, liver, and fat cells do not use insulin well. As a result, your body needs more insulin to help glucose enter cells. At first, the pancreas makes more insulin to keep up with the added demand. Over time, the pancreas can’t make enough insulin, and blood glucose levels rise.

Genes and family history

As in type 1 diabetes, certain genes may make you more likely to develop type 2 diabetes. The disease tends to run in families and occurs more often in these racial/ethnic groups:

• African Americans
• Alaska Natives
• American Indians
• Asian Americans
• Hispanics/Latinos
• Native Hawaiians
• Pacific Islanders

Genes also can increase the risk of type 2 diabetes by increasing a person’s tendency to become overweight or obese.

What causes gestational diabetes?

Scientists believe gestational diabetes, a type of diabetes that develops during pregnancy, is caused by the hormonal changes of pregnancy along with genetic and lifestyle factors.

Insulin resistance

Hormones produced by the placenta contribute to insulin resistance, which occurs in all women during late pregnancy. Most pregnant women can produce enough insulin to overcome insulin resistance, but some cannot. Gestational diabetes occurs when the pancreas can’t make enough insulin.

As with type 2 diabetes, extra weight is linked to gestational diabetes. Women who are overweight or obese may already have insulin resistance when they become pregnant. Gaining too much weight during pregnancy may also be a factor.

Figure \(\PageIndex{1}\). Pregnancy can sometimes contribute to diabetic complications

Hormonal changes, extra weight, and family history can contribute to gestational diabetes.

Genes and family history

Having a family history of diabetes makes it more likely that a woman will develop gestational diabetes, which suggests that genes play a role. Genes may also explain why the disorder occurs more often in African Americans, American Indians, Asians, and Hispanics/Latinas.

What else can cause diabetes?

Genetic mutations, other diseases, damage to the pancreas, and certain medicines may also cause diabetes.

Diagnosing diabetes and prediabetes?

Health care professionals most often use the fasting plasma glucose (FPG) test or the A1C test to diagnose diabetes. In some cases, they may use a random plasma glucose (RPG) test. The FPG blood test measures your blood glucose level at a single point in time. For the most reliable results, it is best to have this test in the morning, after you fast for at least 8 hours. Fasting means having nothing to eat or drink except sips of water.

The A1C test is a blood test that provides your average levels of blood glucose over the past 3 months. Other names for the A1C test are hemoglobin A1C, HbA1C, glycated hemoglobin, and glycosylated hemoglobin test. You can eat and drink before this test. When it comes to using the A1C to diagnose diabetes, your doctor will consider factors such as your age and whether you have anemia or another problem with your blood.1 The A1C test is not accurate in people with anemia.

How can I lower my chances of developing type 2 diabetes?

Research such as the Diabetes Prevention Program shows that you can do a lot to reduce your chances of developing type 2 diabetes. Here are some things you can change to lower your risk:

• Lose weight and keep it off. You may be able to prevent or delay diabetes by losing 5 to 7 percent of your starting weight.1 For instance, if you weigh 200 pounds, your goal would be to lose about 10 to 14 pounds.
• Move more. Get at least 30 minutes of physical activity 5 days a week. If you have not been active, talk with your health care professional about which activities are best. Start slowly to build up to your goal.
• Eat healthy foods most of the time. Eat smaller portions to reduce the amount of calories you eat each day and help you lose weight. Choosing foods with less fat is another way to reduce calories. Drink water instead of sweetened beverages.

Manage Diabetes

Although diabetes has no cure, it can be managed by taking the right steps to stay healthy. The National Institute of Health recommends make the following recommendations for managing diabetes:

• Follow a diabetes meal plan: Choose fruits and vegetables, beans, whole grains, chicken or turkey without the skin, fish, lean meats, and nonfat or low-fat milk and cheese. Drink water instead of sugar-sweetened beverages. Choose foods that are lower in calories, saturated fat, trans fat, sugar, and salt. Learn more about eating, diet, and nutrition with diabetes.
• Engage in physical activity daily: Set a goal to be more physically active. Try to work up to 30 minutes or more of physical activity on most days of the week. Brisk walking and swimming are good ways to move more.
• Take appropriate medicine: Take medicine(s) for diabetes and any other health problems, even when feeling good or having reached a healthy blood glucose, blood pressure, and cholesterol goals.
• Check your blood glucose levels: For many people with diabetes, checking their blood glucose level each day is an important way to manage their diabetes. Monitoring blood glucose levels is most important for anyone taking insulin. The results of blood glucose monitoring can help diabetes sufferers make decisions about food, physical activity, and medicines.

Figure \(\PageIndex{2}\). Measuring Blood Glucose Levels is an important part of managing diabetes. The most common way to check a blood glucose level is at home is with a blood glucose meter. You get a drop of blood by pricking the side of your fingertip with a lancet. Then you apply the blood to a test strip. The meter will show you how much glucose is in your blood at the moment.