How many types of diabetes are there?

While some types of diabetes may not be preventable, all types are treatable.

How many types of diabetes are there? The answer is more complicated than you might think. Although there are three main types of diabetes – Type 1, Type 2 and gestational diabetes – the lines between these are blurring as doctors learn more about the disease and how it affects people at different stages of life.

What is diabetes?

Diabetes is a build-up of sugar – glucose – in the blood that happens when the body doesn't convert the food you eat into energy like it should. Usually, our bodies make a hormone called insulin in the pancreas to help break down food into energy. Sometimes the pancreas stops making insulin, or the body stops being able to use insulin effectively. That's when sugar builds up in the blood, causing high blood sugar, which can lead to a variety of symptoms. The first signs of high blood sugar can include:

• Frequent urination
• Being very thirsty and/or hungry
• Weight loss
• Blurred vision
• Feeling very tired
• Wounds that don't heal
• More infections than usual
• Numbness or tingling in hands or feet

Over a long time, high blood sugar can lead to a wide range of serious complications, such as heart disease, stroke, amputation and loss of eyesight. If diabetes is detected and treated early with medication, diet and exercise, the risk of complications decreases, and the chances of living a long and healthy life increase. If you notice any of the symptoms above, contact your doctor, especially if diabetes runs in your family.

While the signs of diabetes can be similar regardless of the cause, treatment depends on many different factors, including what type of diabetes you have and how long you may have had the condition before being diagnosed.

How many types of diabetes are there?

"There are actually lots of types of diabetes," says Dr. Andrey Manov, a board-certified physician in internal medicine, endocrinology, diabetes and metabolism at MountainView Hospital in Las Vegas, Nevada. If you add up all the types, Dr. Manov explains, as many as 1 in 3 people either have some form of diabetes or are at risk of developing it. He urges anyone who has a family member with diabetes and anyone age 35 or older to get tested for the condition.

If you are diagnosed with diabetes, the type and subtype, as well as other factors, can determine the treatment and recommendations.

Type 1 diabetes

Type 1 diabetes is the least common type of diabetes, according to Dr. Manov. It affects fewer than 1.6 million people in the U.S. The disease usually comes on suddenly, and people with the disease must monitor their blood sugar and take insulin to turn food into energy and keep their blood sugar levels from rising too high. People with Type 1 diabetes can get their insulin via a pump, or by giving themselves a shot.

Type 1 diabetes has several subtypes, Dr. Manov says. The first, Type 1a, is an autoimmune disease, which means the body attacks itself, in this case destroying the cells in the pancreas that produce insulin. In addition to glucose tests and A1C blood tests, doctors will check for certain antibodies that generally indicate Type 1a diabetes. Type 1b diabetes also comes on suddenly, but it is not an autoimmune disease. It occurs mostly in people of Asian or sub-Saharan African origin. Dr. Manov points out that there are other subtypes too.

While Type 1 is most often diagnosed in children, adults can develop Type 1 diabetes as well, and it can be diagnosed at almost any age. It tends to run in families, so if you have a family member with Type 1 diabetes, you have a higher risk of also developing the condition. While not everyone with the risk factors to get Type 1 diabetes will develop the disease, doctors have not found a way to prevent Type 1 diabetes. "I hope in the next years we will have some ways to prevent Type 1 diabetes," says Dr. Manov.

Gestational diabetes

Another type of diabetes occurs during pregnancy. This is called gestational diabetes, and it can cause problems for both pregnant people and their babies. Doctors routinely test for gestational diabetes between 24 and 28 weeks of pregnancy. Eating healthy foods, staying active and avoiding too much weight gain during pregnancy can help reduce your risk of developing this type of diabetes. If you develop gestational diabetes, you may have to take oral insulin to bring your blood sugar down.

Gestational diabetes usually resolves after the baby's birth. Dr. Manov explains that if someone develops diabetes before the 24th week of pregnancy, they likely have Type 2 diabetes and may require ongoing treatment and lifestyle changes to keep their blood sugar under control. If you have had gestational diabetes, you and your children are at higher risk of developing Type 2 diabetes later and should be checked regularly so that it can be detected and treated early.

Type 2 diabetes

Type 2 diabetes is the most common type of diabetes. More than 34 million Americans have been diagnosed with the disease, accounting for more than 90% of all diabetes cases. However, experts think that many, many more Americans may have Type 2 diabetes and do not know it.

While Type 2 diabetes is most often diagnosed in people older than 40, people can develop it at any age. In fact, Type 2 diabetes is on the rise among children and teens, and even infants can develop the disease. Family history plays a role, and so do diet and activity levels.

Type 2 diabetes is treated with medications and lifestyle changes that help to lower blood sugar levels. This may include oral or injected insulin and medicines that help the body process sugar more effectively. Your doctor will work with you to choose the combination that's right for you.

People who are overweight or have obesity are more likely to develop Type 2 diabetes. More than one-third of Americans have obesity, and 1 in 3 are overweight. That means many Americans are at risk of developing Type 2 diabetes. According to Dr. Manov, as many as 80-90 million Americans have a condition called prediabetes, in which blood sugar levels are elevated but not yet to the point of diabetes. People with prediabetes usually go on to develop diabetes, most often Type 2.

The good news is that the results of the Diabetes Prevention Program show you can lower your risk of Type 2 diabetes and even reverse it to some degree by moving more, eating healthy foods and losing weight. Dr. Manov recommends following a Mediterranean diet that emphasizes fresh fruits, vegetables, nuts, fish, lean proteins and healthy fats.

"Diabetes is a treatable disease, and Type 2 can be prevented to a degree with the appropriate way of eating, exercising and keeping weight down," says Dr. Manov.

A balanced diet and regular exercise can help keep you healthy, regardless of your risk level for developing diabetes.