Type 1 diabetes (T1D) is commonly diagnosed in childhood and the teen years. It’s a lifelong condition that requires treatment.

Type 1 diabetes (T1D) is an autoimmune disease that occurs when the immune system attacks and destroys the pancreas’s insulin-producing beta cells.

Over 300,000 young people under 20 years old have T1D in the United States, and the numbers are rising. This lifelong illness has no cure, and researchers are still unsure of its exact cause.

People who are diagnosed with T1D in their teenage years are insulin-dependent for life.

Read on for more information about T1D in teens.

Historically referred to as juvenile diabetes or insulin-dependent diabetes, type 1 diabetes (T1D) is an autoimmune condition in which the body’s immune system accidentally attacks the insulin-producing beta cells of the pancreas, mistakenly identifying them as foreign bodies.

Once attacked, these beta cells no longer produce insulin, which cells need to properly process glucose from the foods we eat. Once diagnosed, people with diabetes make no insulin and must inject insulin to survive, which is critical for the body’s cells to function as they should.

Without it, glucose cannot enter the body’s cells. It overflows into the bloodstream and causes high blood sugar, which, without treatment, is fatal.

T1D can be diagnosed at any age, but is commonly diagnosed during several age ranges: between 4 and 7 years old and again between 10 and 14 years old. This is due to rapid growth spurts and the onset of puberty.

Although many people are diagnosed with T1D in their teenage years, once diagnosed, they will have the condition into adulthood and for the rest of their lives. There is currently no cure for T1D.

In addition to someone generally feeling unwell, the following are the classic signs and symptoms of undiagnosed type 1 diabetes.

If you or someone you know has been experiencing any of the following symptoms for several weeks without improvement, seek emergency medical help immediately:

  • frequent urination
  • rapid weight loss
  • extreme thirst (unquenchable thirst)
  • fruity-smelling breath
  • blurry vision
  • body aches
  • fever
  • sunken in face
  • flushed face

T1D can sometimes be mistaken for the flu or another virus, so if you’re not feeling great and have any of the aforementioned symptoms, call your doctor immediately.

There is no known cause for T1D, but researchers believe it is a combination of genetics and environmentaltriggers, like a virus. A family history of the disease may also play a role.

For someone to develop T1D, they have to inherit risk factors from both parents or experience both genetic risk factors and an environmental trigger, like a virus.

Many people do have a family history of T1D and never go on to develop the condition, and many people develop T1D without a family history.

One 2018 study suggests that children exposed to enteroviruses are more likely to develop T1D.

Other risk factors for T1D include:

  • Gender: Males are more susceptible to T1D than females.
  • Race/ethnicity: Non-Hispanic Caucasians develop T1D the most frequently.
  • Where you live: T1D is more common in countries farther from the equator.
  • Diabetes-related autoantibodies: Having diabetes-related autoantibodies in your body is a risk factor.
  • Low vitamin D levels: Having decreased levels of vitamin D may be a risk factor.
  • Another autoimmune disease: If you have other autoimmune diseases like Celiac disease, multiple sclerosis, rheumatoid arthritis, or lupus, you may be at a higher risk.

An official diagnosis of T1D requires a blood test, where one’s blood glucose is measured (just one drop of blood is required). This will happen either in a doctor’s office or at a hospital with a standard glucometer.

Typically blood glucose levels for someone without diabetes range between 70 and 140 mg/dL.

Someone with a blood glucose level of 126 mg/dL or higher on more than one occasion is indicated for diabetes, but someone with symptomatic T1D can be diagnosed with a blood sugar as high as 900 mg/dL or more and while the patient is in diabetic ketoacidosis (DKA).

Around 40% of cases of T1D are diagnosed with DKA, which is a deadly complication of undiagnosed diabetes in which one’s blood sugar and ketone levels are so high that the blood turns acidic.

One 2019 study noted that the rate of DKA at diagnosis in young people rose from 41% to 58% between 2010 and 2017.

DKA usually sets in after blood sugar levels have surpassed 250 mg/dL for several hours or days, along with the presence of ketones in the blood and urine. It develops when the body cannot metabolize any glucose ingested because there is no insulin available.

This results in rapid deterioration and requires immediate emergency medical attention. A DKA diagnosis is typically made in a hospital.

If a person is indicated for T1D, follow-up blood tests are usually given, including a hemoglobin A1C test, which measures average blood glucose levels over the previous 3-month period, and a C-peptide test to measure the amount of C-peptide in the blood or urine.

This can help healthcare professionals determine whether someone has type 1 or type 2 diabetes. A C-peptide test can also determine whether the pancreas is making insulin.

Physicians may also order an insulin assay test, which measures how much insulin is in the bloodstream.

Typical fasting insulin levels range between 5 and 15 ?U/mL, but with more sensitive assays, normal fasting insulin should be lower than 12 ?U/mL.

Very high circulating levels of insulin, along with high blood sugar, are found in people with severe insulin resistance, which is indicative of type 2 diabetes.

Also, you may request or receive auto-antibody testing, which can show a genetic link to T1D.

The antibodies for which these screening tests check are:

  • islet-cell-cytoplasmic auto-antibodies
  • glutamic-acid-decarboxylase auto-antibodies
  • insulinoma-associated-2 auto-antibodies
  • insulin auto-antibodies
  • zinc-transporter-8 auto-antibodies

If you test positive for one or more of these autoantibodies, it can confirm a T1D diagnosis.

Treating T1D in teens requires strict, lifelong management of blood sugar levels with insulin, diet, and physical activity.

Insulin is almost always only injectable; however, there is one kind of inhalable insulin that is short-acting. People with diabetes must test their blood sugar levels multiple times throughout the day.

You can administer injectable insulin via multiple daily manual injections or with an insulin pump. You can also test blood sugar levels with an at-home glucometer or a continuous glucose monitor (CGM).

Some management systems are an integrated insulin pump and CGM. The insulin pump makes automatic insulin dosing adjustments based on blood sugar levels to help prevent hyper- and hypoglycemia. These systems must be worn continuously to be effective. There is currently no cure for T1D.

Affecting nearly every organ of the body, T1D will affect your teen for life. While it’s manageable, it can cause both short and long-term complications.

The short-term complications of T1D include:

  • high blood sugar levels
  • low blood sugar levels
  • diabetic ketoacidosis (DKA) from dangerously high blood sugars
  • diabetic coma from dangerously low blood sugars
  • cerebral edema (brain swelling from high or low blood sugars)
  • premature death

High blood sugar levels over many years can damage major organ systems.

This may cause the following long-term complications:

  • heart disease, heart attacks
  • stroke
  • nerve damage (neuropathy)
  • lower limb amputations
  • diabetic retinopathy and/or blindness
  • kidney disease or failure
  • premature death

However, with good blood sugar management, people with T1D can live a long, healthy life.

Recent estimates of the reduction in life expectancy for someone with type 1 diabetes range from 7.6 to 19 years. In 2022, the life expectancy for someone with T1D will be longer than ever, ranging from 65 to 72 years old.

In another study, the average life expectancy for people with diabetes was 13 years less than people without diabetes (including both type 1 and type 2 diabetes in the data.)

One older study published in 2015 reported at the age of 20, people with type 1 diabetes would live 12 fewer years than 20-year-olds without the condition.

Another study reports that people with type 1 diabetes who have better blood glucose management lived longer lives than those with worse blood glucose management.

People with T1D are living longer and healthier than ever before, and with improvements in medication and technology, this is getting better every day.

Type 1 diabetes (T1D) is an autoimmune condition commonly diagnosed in childhood and throughout the teenage years. This chronic condition has no known exact cause, and there is currently no known cure.

T1D is diagnosed with a simple blood test — any results of 126 mg/dL or higher on two separate tests indicate diabetes. Follow-up tests may be ordered to confirm a T1D diagnosis.

T1D is often diagnosed when someone is already in DKA, a short-term, deadly complication of high blood sugar levels that can be fatal if not treated immediately.

T1D is managed with daily injections of insulin and the close monitoring of blood sugar levels. Although diabetes can cause many short- and long-term complications, people with diabetes can live long, healthy lives, and people with diabetes are living longer and healthier than ever before.