Type 1 diabetes

Type 1 diabetes
Other namesType 1 diabetes mellitus, insulin-dependent diabetes, insulin-dependent diabetes mellitus (IDDM), juvenile diabetes, childhood-onset diabetes
A blue circle, the symbol for diabetes
Pronunciation
Medical specialtyEndocrinology
SymptomsFrequent urination, increased thirst, weight loss
ComplicationsDiabetic ketoacidosis, severe hypoglycemia, cardiovascular disease, and damage to the eyes, kidneys, and nerves
Usual onsetAt any age; over days to weeks
DurationLifelong
CausesBody does not produce enough insulin
Risk factorsFamily history, celiac disease, autoimmune diseases
Diagnostic methodHigh blood sugar levels, autoantibodies targeting insulin-producing cells
PreventionTeplizumab (Delays onset but does not permanently prevent onset of disease)
TreatmentMonitoring blood sugar, injected insulin, managing diet
Prognosis10-12 years shorter life expectancy
Frequency9 million cases globally

Type 1 diabetes (also called T1D, Type 1 DM, diabetes mellitus type 1), is an autoimmune disease that results in high blood sugar (hyperglycemia). It causes hyperglycemia because the body cannot create enough insulin. Insulin is a hormone that is made in the pancreas that lowers blood sugar. People with this autoimmune disease are called diabetics.

People with type 1 diabetes need to take insulin injections to stay healthy and have a normal or safe level of sugar (glucose) in their blood. Diabetics that do not get enough insulin can become very sick or even die if it goes unchecked. People with type 1 diabetes have an higher risk of developing neuropathy (nerve pain), kidney disease, retinopathy (which affects sight), depression as well as diseases involving blood vessels such as stroke, heart disease or gangrene.[source?]

There are two types of diabetes. About 5-10% of people with diabetes have type 1.[source?] In addition to type 1 and 2 diabetes mellitus there is diabetes insipidus.

3D medical animation still of type 1 diabetes showing insulin production in a diabetic patient and in normal condition.

Cause

Type 1 diabetes is a condition caused by a lack of insulin in the body. Insulin is a hormone produced by beta (B) cells in the pancreas. Insulin is responsible for moving sugars out of the blood and into cells to be used by the body for energy. If insulin is not made, the body will search for other ways to get the sugars needed to feed the cells, including breaking down muscle and fat, leading to a loss of weight and the production of ketones in the body, which can cause ketoacidosis.

In type 1 diabetes, insulin not produced in the pancreas due to an autoimmune condition, where it attacks its own cells. The immune system attacks the cells responsible for producing insulin in the pancreas, called beta cells. The beta cells are damaged in a way that prevents them from producing more insulin. As more and more of these cells are damaged, less insulin is produced in the body. This means that more sugar remains in the bloodstream rather than being moved into cells. This high blood sugar causes the symptoms seen in type 1 diabetes.

The disease is thought to be strongly linked to genetic factors, but the trigger that starts the autoimmune disease is not currently known.

Epidemiology

In the past, type 1 diabetes was generally thought to be a disorder in children and teenagers. However, it has now been found that adults can be diagnosed with the disease.

Although type 1 diabetes can now be diagnosed at any age, it is one of the most common chronic conditions in children and young adults. Being diagnosed at ages 5–7 or at the start of puberty is the most common. Type 1 diabetes is also slightly more common in boys.

Cases of type 1 diabetes have been increasing across the world for several decades. Approximately 1 in 300 people are diagnosed with type 1 diabetes by the age of 18 in the United States.

Symptoms

In type 1 diabetes, symptoms generally develop over a few days or weeks, though may take longer in adults. The main symptoms are:

Nausea, vomiting (being sick) and heavy breathing are more serious symptoms that occur at a later stage in the disease.

Complications

People with type 1 diabetes may have to deal with both short-term and long-term complications, particularly if the disease is not well managed.

Short-term complications

Hypoglycaemia

Hypoglycaemia is when blood sugar levels decrease to below normal. This is most commonly due to overuse of medications for diabetes type 1 like insulin, poor diet control, and rigorous exercise. The risk of suffering from low blood sugar is increased by drinking alcohol. This may lead to various other symptoms, including confusion, loss of consciousness, clumsiness, seizures or death.

Diabetic ketoacidosis

Diabetic ketoacidosis (DKA) is a very serious complication of type 1 diabetes. It is a medical emergency and requires rapid medical attention to prevent further damage to diabetic, because when it is left untreated it can potentially lead to death. DKA occurs when there is not enough insulin in the body to supply sugars to the cells. In order to give its cells enough energy to survive, the body begins to produce acidic ketones which are then used to feed energy to the cells.

If too many ketone bodies build up the blood becomes acidic, damaging the body and leading to the symptoms:

Treatment induced neuropathy in diabetes (TIND)

Another short-term complication is treatment induced neuropathy in diabetes (TIND). This leads to nerve pain and retinopathy, both of which persist for a few months to years. The cause is known to be a sudden drop in HbA1c, at least 3 percentage points within 3 months. This means that slowly reducing high long term blood sugar values (measured by HbA1c) is important.

Long-term complications

If diabetes is not treated, even mildly raised blood sugar levels can damage nerves, organs and blood vessels in the body.

Small blood vessel complications

Large blood vessel complications

Management

There is no known cure for diabetes. Instead, treatment is designed to help keep blood sugar levels normal in order to reduce the chances of complications developing as the disease progresses. There are two main method that are combined to manage diabetes type 1:

Lifestyle

  • Healthy eating: eating a diet focused on fruit and vegetables, whilst limiting fats, salt, and sugar helps keep blood sugar levels in check
  • Exercise: regular physical activity helps to lower blood sugar level to normal. A good goal to aim for is 150 minutes of exercise a week[source?]
  • Stopping smoking: smoking further increases the risk of heart disease, peripheral arterial disease (PAD), and stroke. Stopping or reducing smoking will reduce the risk of these complications
  • Reducing alcohol: alcohol can either raise or lower blood sugar, and makes it difficult to monitor your own blood sugar levels. Drinking less alcohol can reduce these risks

Insulin injections

Type 1 diabetes occurs due to the bodies inability to produce its own insulin. To counter this, insulin can be injected into the blood manually. When diabetes is first diagnosed, a plan should be made for insulin treatment in order to not under or overdose, which can lead to serious complications. A diabetic should monitor their own blood sugar levels continuously to know whether they need a dose of insulin to lower their blood sugar.

There are different kinds of insulin that can be taken:

  • Rapid-acting insulin and short-acting insulin get insulin into the bloodstream very quickly. They are typically taken before a meal to prepare for the rise in blood sugar that follows eating food
  • Long acting insulin provides insulin in the system for up to 24 hours. It is generally taken once a day

References

  1. ↑ Zheng, Yan; Permanyer, Iñaki; Canudas-Romo, Vladimir; Aburto, José Manuel; Nigri, Andrea; Plana-Ripoll, Oleguer (2023). "Lifespan variation among people with a given disease or condition". PLOS ONE. 18 (9) e0290962. Bibcode:2023PLoSO..1890962Z. doi:10.1371/journal.pone.0290962. ISSN 1932-6203. PMC 10473533. PMID 37656703.
  2. ↑ Livingstone, Shona J.; Levin, Daniel; Looker, Helen C.; Lindsay, Robert S.; Wild, Sarah H.; Joss, Nicola; Leese, Graham; Leslie, Peter; McCrimmon, Rory J.; Metcalfe, Wendy; McKnight, John A.; Morris, Andrew D.; Pearson, Donald W. M.; Petrie, John R.; Philip, Sam (2015-01-06). "Estimated life expectancy in a Scottish cohort with type 1 diabetes, 2008-2010". JAMA. 313 (1): 37–44. doi:10.1001/jama.2014.16425. ISSN 1538-3598. PMC 4426486. PMID 25562264.
  3. ↑ Arffman, Martti; Hakkarainen, Pirjo; Keskimäki, Ilmo; Oksanen, Tuula; Sund, Reijo (April 2023). "Long-term and recent trends in survival and life expectancy for people with type 1 diabetes in Finland". Diabetes Research and Clinical Practice. 198 110580. doi:10.1016/j.diabres.2023.110580. ISSN 1872-8227. PMID 36804193.
  4. ↑ "Diabetes". World Health Organization. 14 November 2024. Type 1 diabetes. Archived from the original on 15 November 2024. Retrieved 28 August 2025. In 2017 there were 9 million people with type 1 diabetes; the majority of them live in high-income countries.
  5. ↑ "MeSH Browser". meshb.nlm.nih.gov. Retrieved 2026-04-21.
  6. ↑ Type 1 Diabetes, NHS Choices, http://www.nhs.uk/Conditions/Diabetes-type1/pages/introduction.aspx Archived 2015-11-12 at the Wayback Machine. Accessed 09/11/2015
  7. 1 2 Daneman D (2006). Type 1 diabetes. The Lancet 367(9513): 847-858 http://www.sciencedirect.com/science/article/pii/S0140673606683414
  8. ↑ Atkinson MA et al. Type 1 Diabetes. The Lancet 2014; 383(9911): 69-82
  9. ↑ Harjutsalo V, Sjoberg L, Tuomilehto J. Time trends in the incidence of type 1 diabetes in Finnish children: a cohort study. Lancet 2008 ;371: 1777–82
  10. ↑ Maahs DM et al. Chapter 1: Epidemiology of Type 1 Diabetes. Endocrinol Metab Clin North Am 2010; 39(3): 481-497
  11. 1 2 Type 1 Diabetes - Symptoms, NHS Choices, http://www.nhs.uk/Conditions/Diabetes-type1/Pages/Symptoms.aspx Archived 2015-11-05 at the Wayback Machine. Accessed 09/11/2015
  12. ↑ Hypoglycemia. National Institute of Diabetes and Digestive and Kidney Diseases. October 2008. http://www.niddk.nih.gov/health-information/health-topics/Diabetes/hypoglycemia/Pages/index.aspx Archived 2015-07-01 at the Wayback Machine. Retrieved 9 November 2015
  13. 1 2 Diabetes Complications - Diabetic Ketoacidosis, Diabetes UK, http://www.diabetes.co.uk/diabetes-complications/diabetic-ketoacidosis.html. Accessed 09/11/2015
  14. ↑ Gibbons, Christopher H. (July 2020). "Treatment induced neuropathy of diabetes". Autonomic Neuroscience: Basic & Clinical. 226 102668. doi:10.1016/j.autneu.2020.102668. ISSN 1872-7484. PMID 32247944.
  15. ↑ Diabetes Type 1 - Complications, NHS Choices, http://www.nhs.uk/conditions/Diabetes-type1/Pages/Complications.aspx Archived 2015-11-26 at the Wayback Machine. Accessed 09/11/2015
  16. ↑ Fowler MJ. Microvascular and Macrovascular Complications of Diabetes. Clinical Diabetes 2008; 26(2): 77-82
  17. ↑ Diabetes Type 1 - Living With, NHS Choices, http://www.nhs.uk/Conditions/Diabetes-type1/Pages/living-with.aspx Archived 2015-12-05 at the Wayback Machine. Accessed 09/11/2015
  18. ↑ Diabetes Type 1 - Treatment, NhS Choices, http://www.nhs.uk/Conditions/Diabetes-type1/Pages/Treatment.aspx Archived 2015-11-10 at the Wayback Machine. Accessed 09/11/2015
  19. ↑ Patient Information: Diabetes mellitus type 1: Insulin treatment (Beyond the Basics), UpToDate, http://www.uptodate.com/contents/diabetes-mellitus-type-1-insulin-treatment-beyond-the-basics. Accessed 09/11/2015