Facts About Diabetes

Diabetes, also called diabetes mellitus, is a condition that affects insulin, a hormone that breaks down sugars in the food you eat and converts them into glucose to fuel the body.

What You Need to Know

  • There are three types of diabetes: type 1, type 2 and gestational. Type 2 is the most common, and cases of both type 1 and type 2 are on the rise.
  • Diabetes is diagnosed with one or more blood tests.
  • Diabetes may be managed with monitoring, medication, diet and lifestyle changes.

What is diabetes?

Diabetes occurs when your body does not process food as energy properly. Insulin is a critical hormone that gets glucose (sugar that is used as energy) to the cells in your body. When you have diabetes, your body either doesn’t respond to insulin or doesn’t produce insulin at all. This causes sugars to build up in your blood, which puts you at risk of dangerous complications.

Types of Diabetes

Diabetes can be classified as type 1, type 2 or gestational.

Type 1 Diabetes

Type 1 diabetes is an autoimmune disease in which the immune system attacks and destroys the cells in the body that produce insulin. The rate of type 1 diabetes is rising worldwide, with the greatest increase occurring in children younger than age 5.

In people with type 1 diabetes, the body does not make enough of the hormone insulin, which enables the body to convert glucose (a simple sugar) into energy. Type 1 diabetes develops when the insulin-producing beta cells in the pancreas are destroyed due to an autoimmune process in which the body’s immune system mistakenly destroys its own organs or tissues. The onset of symptoms can happen quickly. People with type 1 diabetes may need daily insulin shots.

Type 2 Diabetes

Type 2 diabetes is a metabolic disorder that results from the body’s inability to make enough insulin or to properly use insulin. Type 2 diabetes is the most common type of diabetes. In type 2 diabetes, the pancreas produces enough insulin, but the body cannot use it effectively. This is referred to as insulin resistance. Gradually, insulin production slows down, as is the case in type 1 diabetes. Previously unheard of in children and teens, type 2 diabetes is now being diagnosed more often in children and teens, which some research links to increasing rates of childhood obesity.

Gestational Diabetes

Gestational diabetes develops during pregnancy when a hormone made by the placenta prevents the mother’s body from using insulin effectively. It is not caused by a lack of insulin but by other hormones produced during pregnancy that can make insulin less effective. Gestational diabetic symptoms disappear following delivery of the baby.


In a condition called prediabetes, the blood sugar level is elevated but not to a degree that constitutes diabetes. People who have repeated tests showing elevated fasting glucose have increased risk of developing full-blown diabetes. Those over age 45 should be tested for prediabetes or diabetes. If a first blood glucose test is normal, individuals should be retested every three years.

Those under age 45 should consider testing for prediabetes or diabetes if they have a body mass index (BMI) greater than or equal to 25 kg/m2 and have several risk factors, such as a sedentary lifestyle, taking certain medications (including some antipsychotic, steroid, diuretic medicines) or having a family history of the disease.

Diabetes Symptoms

Depending on the type, diabetes can cause too much glucose in the blood or too little.

Hyperglycemia (High Blood Sugar)

Diabetes is characterized by a failure to secrete enough insulin. Insulin is a hormone produced in the pancreas. It is needed by the body to convert glucose into energy. Without adequate insulin, abnormally high levels of glucose accumulate in the blood.

Hypoglycemia (Low Blood Sugar)

Hypoglycemia is characterized by a blood sugar (glucose) level that is too low to fuel the body’s normal functioning. Hypoglycemia may be a condition by itself, a complication of diabetes or a sign of another disorder.

Problems with blood sugar regulation due to diabetes can cause:

  • Headaches
  • Increased thirst
  • Frequent urination
  • Increased appetite
  • Weight loss
  • Blurred vision
  • Fatigue
  • Dry mouth

If your child develops any of the above symptoms, consult a pediatrician immediately.

Note: Even though type 1 diabetes may take years to develop, the onset of symptoms is fairly sudden and rapid. Undiagnosed and untreated, a person with type 1 diabetes can go into a life-threatening diabetic coma (ketoacidosis). Symptoms of type 2 diabetes are the same as the symptoms of type 1 diabetes, but unlike type 1 diabetes, symptoms tend to develop slowly and gradually.

Diabetes Diagnosis

A doctor can diagnose diabetes with one or more of the following blood tests:

  • Random blood sugar test: Taken any time, regardless of how recently you have eaten.
  • A1C test: Assesses blood sugar levels over several months.
  • Fasting blood sugar test: Measures blood sugar levels after you have not eaten overnight.
  • Glucose tolerance test: Takes blood levels over the course of several hours to show how quickly your body metabolizes the glucose in a special liquid you drink.

Diabetes Treatment

Treatment for diabetes depends on its type and severity, and may include:

  • Frequent blood glucose checking to monitor blood glucose levels
  • Lifestyle changes, including diet and exercise
  • Oral medication
  • Daily insulin injections

Regular physical exams are critical for people with any type of diabetes to monitor and treat any arising complications, such as eye problems, kidney disease, cardiovascular disease and neuropathy (damage to the nerves).


Wellness and Prevention

Research Shows Biomedical Discoveries Underpin Good Health

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Virtually every major medical breakthrough in the past half-century has been achieved because a biomedical scientist unraveled one more mystery of biology. The discoveries of Johns Hopkins scientists have led to vaccine, treatment and diagnostic breakthroughs. The Johns Hopkins Institute for Basic Biomedical Sciences continues the legacy by leading research into the causes and treatments of numerous biomedical conditions.