The term “diabetes” is often used to refer to the health condition in general, but how many types of diabetes are there? Diabetes is a condition in which your glucose (blood sugar) levels are too high. There are several types of diabetes, but they all result from the body either not having enough insulin or not using this hormone properly.

Not everyone with diabetes has actually received the diagnosis. Nearly 23 percent of people with diabetes don’t realize they have it, according to the Centers for Disease Control and Prevention (CDC). Most forms of diabetes are chronic — they last throughout life and can be treated but not cured. Diabetes is technically called diabetes mellitus, although this term isn’t as commonly used.

This article explores the six types of diabetes, including each type’s causes, risk factors, and treatment options.

1. Type 1 Diabetes

Type 1 diabetes, which affects about 5 percent of people with diabetes, was previously called juvenile diabetes. It is most often diagnosed in children or young adults and can sometimes have a sudden and serious onset, including a potentially life-threatening condition called diabetic ketoacidosis. In type 1 diabetes, the body stops producing insulin, a hormone that helps cells absorb glucose from the blood to use for energy.

Type 1 diabetes is an autoimmune condition, meaning the immune system mistakenly attacks and destroys beta cells (cells in the pancreas that produce insulin). When more than 80 percent of these beta cells are destroyed, blood sugar levels become hard to control and diabetes symptoms appear. In some cases, blood tests can detect specific antibodies years before a person develops symptoms.

People with type 1 diabetes rely on insulin therapy to survive, which is why it’s sometimes called “insulin-dependent diabetes.”

2. Type 2 Diabetes

Type 2 diabetes is the most common type of diabetes. About 1 in 10 people in the U.S. have diabetes, and of those, 90 percent to 95 percent have type 2. Type 2 diabetes is most commonly diagnosed in adults age 45 or older but may also occur in younger adults and children.

Unlike people with type 1 diabetes, those with type 2 diabetes still produce insulin. However, as type 2 develops, the body’s cells gradually become resistant to insulin. This condition, called insulin resistance, means cells can no longer take up glucose effectively, leading to higher blood glucose levels. Over time, elevated blood glucose can damage nerves (neuropathy), blood vessels, and organs, especially the kidneys (diabetic nephropathy) and eyes (diabetic retinopathy).

Some people manage their condition with medical treatments for type 2 diabetes, diet, and physical activity without needing insulin. Others with more severe type 2 diabetes may require insulin injections in addition to diabetes medications.

What Is the Main Cause of Type 2 Diabetes?

The main cause of type 2 diabetes is insulin resistance. Several factors can contribute to insulin resistance, including:

• Genetics
• Obesity or being overweight
• Sedentary lifestyle
• Unhealthy diet
• Medication
• Hormone imbalances

Racial and ethnic background may also increase the risk of type 2 diabetes. For example, according to Mayo Clinic, Hispanic, Black, Asian American, and American Indian people have a higher risk of type 2 diabetes, though the reason for this is unclear.

Family history may be a risk factor for all types of diabetes. Many DiabetesTeam members share that diabetes has affected several of their family members. “My father and his mother both had diabetes, type 2. I have had it for more than 25 years,” one member said.

Is It Possible To Have Both Type 1 and Type 2 Diabetes?

It’s rare but possible for someone who has type 1 diabetes to develop insulin resistance, resulting in “double diabetes.” Double diabetes can be difficult to treat. A person with both types of diabetes must continue to take insulin and add medications for type 2 that increase insulin sensitivity. Lifestyle changes such as losing weight, increasing exercise, and improving eating habits are vital to avoid severe complications.

3. Prediabetes

Doctors diagnose prediabetes (also called impaired glucose tolerance or impaired fasting glucose) when blood glucose test results are higher than normal, but not yet as high as those seen in type 2 diabetes. Prediabetes indicates that someone is becoming insulin resistant and may progress to type 2 diabetes without treatment.

Prediabetes can often be reversed with significant weight loss, healthy dietary changes, and increased physical activity. In some cases, health care providers may prescribe medication to help manage blood glucose levels. One DiabetesTeam member who reported that their prediabetes was reversed: “I’m celebrating. I’m glad that I gained a lifestyle. There’s no going back from here.”

4. Gestational Diabetes

Gestational diabetes affects between 2 percent and 10 percent of U.S. pregnancies each year, and screening for it is a routine part of prenatal care. Testing typically occurs during the second trimester but may be done earlier if the pregnant person has risk factors, such as a high body mass index (BMI) or a family history of diabetes. Although gestational diabetes often doesn’t cause noticeable symptoms of diabetes, it can lead to complications, including a larger-than-average newborn size, which may affect delivery. It also raises the risk of the child developing obesity and type 2 diabetes later in life.

Gestational diabetes typically disappears after pregnancy. However, about 50 percent of people who have gestational diabetes later develop type 2 diabetes. One DiabetesTeam member wrote, “Had gestational diabetes with my pregnancy. Ten years later, type 2 diabetes … textbook. My maternal grandmother also had diabetes, and I tend to take after her healthwise.”

Between 30 percent and 69 percent of people who develop gestational diabetes will have it again during another pregnancy.

5. Monogenic Diabetes

Monogenic diabetes is a rare form of diabetes caused by a mutation (variant, or change) in a single gene and makes up 2 percent to 3 percent of diabetes cases diagnosed before age 35, according to Diabetes in America. The mutated gene is usually inherited from one or both parents but can also happen spontaneously. The genetic change that causes monogenic diabetes prevents the body from making enough insulin, and glucose levels rise because the cells can’t take in enough glucose from the blood.

6. Secondary Diabetes

Secondary diabetes is a type of diabetes that results from another health problem or use of certain medications. Managing high blood glucose in secondary diabetes depends on the underlying cause.

Health conditions that may lead to secondary diabetes include:

• Polycystic ovary syndrome (PCOS)
• Pancreatic cancer
• Chronic pancreatitis (inflammation of the pancreas)
• Glucagonoma, a rare pancreatic tumor
• Cystic fibrosis
• Cushing’s syndrome
• Hemochromatosis, which causes excess iron buildup
• Pheochromocytoma, a benign adrenal gland tumor
• Thyroid disorders

Medications that may cause secondary diabetes (drug-induced diabetes) include:

• Beta-blockers
• Corticosteroids
• Thiazide diuretics
• Atypical antipsychotics
• Immunosuppressants

Sometimes secondary diabetes can be reversed if the underlying condition is treated in time. For example, diabetes caused by hemochromatosis or glucagonoma may go away if these conditions are successfully treated early on.

Diabetes Insipidus: Similar to but Different From Diabetes Mellitus

Not a type of diabetes mellitus, diabetes insipidus is a rare condition usually caused by problems in the brain (pituitary gland) or kidneys. Similar to diabetes mellitus, diabetes insipidus causes excessive thirst and urination.

Diabetes mellitus and diabetes insipidus were named in the Middle Ages, when doctors commonly tasted people’s urine for clues about the sickness. “Mellitus” is Latin for “honey,” indicating that the urine of people with this type of diabetes tastes sweet. “Insipidus” is Latin for “tasteless,” indicating that the urine of people with this condition had no flavor. Diabetes insipidus is not curable, but it’s treatable.

Talk With Others Who Understand

On DiabetesTeam, the social network for people with type 2 diabetes and their loved ones, more than 159,000 members come together to ask questions, give advice, and share their stories with others who understand. Many members also live with fatty liver disease.

Have you been diagnosed with diabetes? Which type do you have, and how do you manage it? Share your experience in the comments below, or start a conversation by posting on your Activities page.