What is diabetes?

There are four major types of diabetes and there are many other types of diabetes due to genetic mutations, health conditions, and other factors.
There are four major types of diabetes and there are many other types of diabetes due to genetic mutations, health conditions, and other factors.

Diabetes mellitus, the condition commonly referred to as diabetes, is a disease that affects how your body makes and handles the hormone insulin. This hormone directly affects your blood sugar (glucose) levels by allowing sugar to enter cells. Cells then use sugar for energy. Diabetes results when your body either can’t make enough insulin or becomes resistant to the insulin it makes.  

There are several ways that diabetes develops. One way this happens is when insulin-producing cells in the pancreas are damaged, causing no or low insulin. Without insulin, sugar remains in the blood rather than going into cells that need energy. The result is a low blood level of insulin and a high blood sugar level. 

The second way that diabetes happens is when the pancreas makes insulin, but body cells become resistant to its effect. If cells do not respond to insulin, they will not let sugar enter. In this case, blood insulin levels are high, and blood sugar levels remain high. In both cases, other health problems result when sugar levels in the blood remain high over time.

Over 37.3 million American adults have diabetes. The most common types of diabetes are diabetes type 1 and type 2. However, there are several other types of diabetes identified, as well as new categories suggested from current research. 

What are the major types of diabetes?

According to the Centers for Disease Control and Prevention (CDC), the three main types of diabetes are diabetes type 1, type 2, and gestational diabetes. The CDC also mentions  prediabetes as a type. 

Diabetes type 1 

Type 1 occurs when your immune system attacks insulin-producing beta cells in your pancreas, an autoimmune disease. Type 1 diabetes results in damaged pancreas cells that can’t produce insulin. Without insulin, high blood sugar levels result. 

About 5% to 10% of people with diabetes have type 1. With this type, symptoms of diabetes develop quickly and most often in children or young adults. However, it can occur at any age. 

Symptoms include the following:

  • Frequent urination
  • Feeling thirsty
  • Losing weight rapidly
  • Feeling hungry
  • Having blurry vision
  • Numbness or tingling in hands or feet
  • Feeling extremely tired
  • Having dry skin and sores that heal slowly
  • Having more infections than usual

Diabetes type 1 can be controlled by continuously monitoring blood sugar levels and taking insulin as needed. There are no known ways to prevent type 1 diabetes.

Diabetes type 2 

Diabetes type 2 is the most common form. Approximately 90% to 95% of people with diabetes have type 2. With diabetes type 2, your body can’t use insulin properly, which increases blood sugar levels. 

While most commonly found in adults, children can also be diagnosed with type 2 diabetes. It can take years to develop and may not show symptoms. Its symptoms are similar to but milder than diabetes type 1. However, if left untreated, diabetes type 2 can cause complications that affect the eyes, heart, and feet. 

Testing blood sugar levels are necessary for diagnosis. For diabetes treatment, you’ll need to regularly monitor your blood sugar levels and take insulin or diabetes medication to control them. Lifestyle changes can prevent type 2 diabetes, including weight loss, healthy eating, and exercise.

Gestational diabetes

Gestational diabetes develops during pregnancy. It occurs in women who have never had diabetes. With gestational diabetes, you and your baby can be at a higher risk of health problems. 

Gestational diabetes may not show any symptoms. A blood test at 24 to 28 weeks of pregnancy diagnoses gestational diabetes. It usually goes away after your baby is born. But it can increase your risk of developing diabetes type 2 later in life. It can also increase the risk of your baby experiencing obesity or diabetes type 2 later in life.

Prediabetes

In America, about 96 million adults have prediabetes. If you have prediabetes, your blood sugar levels are higher than normal, but not high enough to be diagnosed as diabetes type 2. Prediabetes increases your risk of developing diabetes type 2, heart problems, and stroke. You can reverse the condition by regularly monitoring your blood sugar levels and changing your lifestyle.

Other types of diabetes

Apart from the main types, there are other types of diabetes caused by genetic mutations, health conditions, or other factors.

They are as follows: 

Latent autoimmune diabetes in adults (LADA)

This type of diabetes has features of diabetes type 1 and type 2. It is often called diabetes type 1.5. Studies are currently underway to understand how it is different from diabetes type 1 and 2.

Diabetes type 3

The term diabetes type 3 was first proposed in a 2005 research review, to explain how insulin resistance can lead to Alzheimer’s disease, a type of dementia

Another research review in 2018 showed that people with diabetes type 2 have a higher risk of developing Alzheimer’s disease. Type 3 is not officially an accepted diabetes type. However, it is currently under research.

Diabetes type 4

Diabetes type 4 describes diabetes caused by age-related insulin resistance in people who are not overweight or obese. Type 4 is not an officially recognized category. Studies only looked at animals, like mice, and have not included humans.

Maturity onset diabetes of the young (MODY)

MODY is different from diabetes type 1 and 2. It is a rare, genetic type of diabetes. Up to 2% of all people with diabetes in America who are 20 or younger may develop this condition.

Caused by a change or mutation in a single gene, it is a monogenic condition. This mutation affects insulin production, resulting in high blood sugar levels. If one of your parents has this mutation, you have a 50% chance of getting it. Those who inherit this gene mutation develop MODY before they turn 25, regardless of their lifestyle.

Neonatal diabetes

Neonatal diabetes is another type of monogenic diabetes, occurring due to a mutation in a single gene. Typically, diagnosis occurs between 6 and 12 months of age. A rare condition, it affects 1 out of 400,000 American infants. 

Neonatal diabetes is often confused with diabetes type 1. Its symptoms include frequent urination, rapid breathing, and dehydration. Diagnosis is by testing sugar levels in the blood or urine.

Diabetes type 3c 

Type 3c diabetes happens when the pancreas is damaged or removed. Other diseases affecting the pancreas like pancreatic cancer, pancreatitis, or hemochromatosis can damage the insulin-producing cells, resulting in diabetes type 3c.

Wolfram syndrome

Wolfram syndrome is a rare genetic disorder that includes four presenting features:  diabetes insipidus (a condition unrelated to blood sugar but characterized by increased urine output), diabetes mellitus, optic atrophy, and deafness.

Alström syndrome

Alström Syndrome is a rare, genetically inherited syndrome, characterized by common findings.  One finding is insulin resistance in childhood, leading to type 2 diabetes.

Steroid-induced diabetes

Steroids can cause diabetes in people who are otherwise at risk of developing diabetes type 2.

Cystic fibrosis-related diabetes

This type of diabetes occurs in people with cystic fibrosis. It has features similar to diabetes types 1 and 2. 

Check your blood sugar levels 

If you suspect diabetes, get your blood sugar levels checked. Your doctor may also check your family history of diabetes. They may prescribe insulin or diabetic medication and suggest lifestyle changes to reverse the condition.

SLIDESHOW

Diabetes: What Raises and Lowers Your Blood Sugar Level? See Slideshow

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Medically Reviewed on 3/24/2022
References
SOURCES:

Center for Disease Control and Prevention: "Diabetes Symptoms," "Insulin Resistance and Diabetes," "What is Diabetes?"

Diabetes UK: "Monogenic Diabetes (Neonatal Diabetes Mellitus & MODY)," "Types of Diabetes."

Frontiers in Neuroscience: "Insulin Resistance in Alzheimer's Disease."

Journal of Alzheimer's Disease: "Impaired insulin and insulin-like growth factor expression and signaling mechanisms in Alzheimer's disease--is this type 3 diabetes?"

National Institutes of Health: “What is Diabetes?"

Nature: "Depletion of Fat Tregs Prevents Age-Associated Insulin Resistance."

Salk: "FAQ on Type 4 Diabetes.”