What is type 2 diabetes?

Type 2 diabetes is when your body can’t make enough insulin, or use it well. Insulin helps your cells use sugar (glucose) for energy. Without insulin, glucose builds up in your blood. This leads to high blood sugar.

Type 2 diabetes is an ongoing (chronic) disease. It has no known cure. It's the most common type of diabetes.

What causes type 2 diabetes?

The exact cause of type 2 diabetes is not known. It seems to run in families. But it often takes other factors to bring on the disease. These include:

• Being overweight

• Not getting enough physical activity

• Taking certain medicines

Who is at risk for type 2 diabetes?

Risk factors include:

• Age. People ages 45 and older are at higher risk for diabetes.

• Family history of diabetes. The condition tends to run in families.

• Extra weight. Being overweight puts you at higher risk.

• Lack of exercise. Not enough physical activity also puts you at risk.

• Taking certain medicines. These include steroids, some water pills (diuretics), and medicines for mental health (antipsychotics).

• Race and ethnicity. People who have African, Hispanic, Asian, Pacific Island, or American Indian heritage are more likely to develop type 2 diabetes.

• Gestational diabetes. Having diabetes in pregnancy puts you at higher risk of type 2 diabetes later.

• Low HDL. This means low levels of the "good" cholesterol.

• A high triglyceride level. This is a type of blood fat.

• Smoking. Being a smoker puts you at higher risk.

• Other health problems. Some health problems are linked with type 2 diabetes. These include polycystic ovary syndrome, patches of darker skin (acanthosis nigricans) , or being born at a low birth weight. Type 2 diabetes is often preceded by a "pre-diabetes" period, during which weight loss and certain medications can prevent a person from developing type 2 diabetes.

What are the symptoms of type 2 diabetes?

Symptoms may include:

• Frequent bladder infections

• Skin infections that don't heal easily

• Feeling very thirsty

• Peeing often

• Weight loss

• Blurred vision

• Nausea and vomiting

• Feeling very weak and tired

• Irritability and mood changes

• Dry, itchy skin

• Tingling or loss of feeling in the hands or feet

Some people who have type 2 diabetes don’t have symptoms. Symptoms may be mild and you may not notice them. Half of all Americans who have diabetes don't know it.

The symptoms of type 2 diabetes may feel like other health problems. See your healthcare provider for a diagnosis.

How is type 2 diabetes diagnosed?

Diabetes can be diagnosed with several tests. It's best to repeat the tests a second time to confirm the results. The tests include:

• Hemoglobin A1C test. This is the A1C test. It measures your average blood glucose for the past 2 to 3 months. An A1C of 6.5% or higher means you have diabetes. Some conditions can affect how accurate the A1C test is. These conditions include sickle cell disease, pregnancy , glucose-6-phosphate dehydrogenase deficiency, HIV, hemodialysis, recent blood loss or transfusion, and erythropoietin therapy.

• Fasting plasma glucose (FPG). This test checks your blood glucose levels after 8 hours of fasting. You usually get this test before your first meal of the day. This is called your fasting blood glucose level. A result higher than or equal to 126 mg/dL means you have diabetes.

• Oral glucose tolerance test (OGTT). For this test, your glucose level is measured before and then after 2 hours after you drink a sugary drink. This shows how well your body processes glucose. A result of 200 mg/dL or higher after 2 hours means you have diabetes.

• Random glucose test. This blood test is done at any time of the day. Blood glucose of 200 mg/dL or higher with symptoms of high blood sugar means you have diabetes.

If you don't have any symptoms of hyperglycemia, you will need to have 2 abnormal test results from the same sample or in 2 separate test samples to be diagnosed. For example: a fasting plasma glucose greater than 126 and an A1C greater than 6.5% from the same sample.

How is type 2 diabetes treated?

Treatment will depend on your symptoms, age, and general health. It will also depend on how severe the condition is.

The goal of treatment is to keep blood sugar levels as close to normal as possible, but not too low. To do this, you will need to control your blood sugar. You will need to check it regularly.

You may be able to control your type 2 diabetes with:

• Weight loss

• Exercise

• Healthy eating habits

But you may also need to take medicine or insulin.

Treatment may include some or all of these:

• Being more active. Get at least 150 minutes a week of exercise or physical activity. Don’t let more than 2 days go by without being active. When sitting for long periods of time, get up for light activity every 30 minutes.

• Meal planning. You will need to eat foods that don’t cause your blood sugar to rise too quickly. Your healthcare provider will give you resources about what foods to plan your meals around.

• Weight loss. Losing just 5% to 7% of your body weight can help. Talk with your healthcare provider about ways to help you lose weight.

• Taking medicine. There are different types of medicines to treat type 2 diabetes. Each type works in a different way to lower blood sugar. You may take one or more medicines to improve your blood sugar control.

• Taking insulin. If oral medicines don’t work well for you, you may need to inject insulin into your body.

• Getting blood tests. You will need to have your A1C level checked several times a year. Experts advise testing at least twice a year if your blood sugar level is in the target range and stable. You will need this test more often if your blood sugar level is not stable.

• Routine healthcare. Keep all appointments. This is so your healthcare provider can track your diabetes. You will also need to check your feet daily. This is to look for injuries, sores, or infection. These can lead to severe foot problems.

What are possible complications of type 2 diabetes?

Diabetes that is not treated or controlled well can cause problems. These can include problems with:

• Kidneys

• Legs

• Feet

• Eyes

• Heart

• Nerves

• Blood flow

This can lead to:

• Heart failure

• Kidney failure

• Gangrene

• Amputation of feet

• Blindness

• Stroke

For these reasons, it is important to follow a strict treatment plan.

Key points about type 2 diabetes

• Type 2 diabetes is when your body can’t make enough insulin, or use it well.

• Insulin helps the cells in your body absorb glucose for energy. Without insulin, too much glucose is left in the blood. This causes high blood sugar.

• Type 2 diabetes is a chronic disease. It has no known cure. It is the most common type of diabetes.

• The exact cause of type 2 diabetes is not known. It tends to run in families.

• Diabetes that is not treated or controlled can lead to serious health problems.

• The goal of treatment is to keep your blood sugar levels as close to normal as possible, but not too low. You will need to control your blood sugar. You will need to get physical activity, plan meals, and get regular healthcare.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

• Know the reason for your visit and what you want to happen.

• Before your visit, write down questions you want answered.

• Bring someone with you to help you ask questions and remember what your provider tells you.

• At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

• Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.

• Ask if your condition can be treated in other ways.

• Know why a test or procedure is recommended and what the results could mean.

• Know what to expect if you do not take the medicine or have the test or procedure.

• If you have a follow-up appointment, write down the date, time, and purpose for that visit.

• Know how you can contact your provider if you have questions.