What Is Type 1 Diabetes: Causes and Symptoms?

While type 2 diabetes is often preventable, type 1 diabetes mellitus is not.1 Type 1 diabetes is an autoimmune disease in which the immune system destroys cells in the pancreas.

Typically, the disease first appears in childhood or early adulthood. Type 1 diabetes used to be known as juvenile-onset diabetes or insulin-dependent diabetes mellitus (IDDM), but the disease can have an onset at any age.

Type 1 diabetes makes up around 5% of all cases of diabetes.

What is type 1 diabetes?

Children selecting fruit to eat.
Type 1 diabetes usually first appears in childhood or adolescence.

In type 1 diabetes, the pancreas is unable to produce any insulin, the hormone that controls blood sugar levels.

Insulin production becomes inadequate for the control of blood glucose levels due to the gradual destruction of beta cells in the pancreas. This destruction progresses without notice over time until the mass of these cells decreases to the extent that the amount of insulin produced is insufficient.

Type 1 diabetes typically appears in childhood or adolescence, but its onset is also possible in adulthood.

When it develops later in life, type 1 diabetes can be mistaken initially for type 2 diabetes. Correctly diagnosed, it is known as latent autoimmune diabetes of adulthood.

Causes of type 1 diabetes

The gradual destruction of beta cells in the pancreas that eventually results in the onset of type 1 diabetes is the result of autoimmune destruction. The immune system turning against the body’s own cells is possibly triggered by an environmental factor exposed to people who have a genetic susceptibility.

Although the mechanisms of type 1 diabetes etiology are unclear, they are thought to involve the interaction of multiple factors:

  • Susceptibility genes – some of which are carried by over 90% of patients with type 1 diabetes. Some populations – Scandinavians and Sardinians, for example – are more likely to have susceptibility genes
  • Autoantigens – proteins thought to be released or exposed during normal pancreas beta cell turnover or injury such as that caused by infection. The autoantigens activate an immune response resulting in beta cell destruction
  • Viruses – coxsackievirus, rubella virus, cytomegalovirus, Epstein-Barr virus and retroviruses are among those that have been linked to type 1 diabetes
  • Diet – infant exposure to dairy products, high nitrates in drinking water and low vitamin D intake have also been linked to the development of type 1 diabetes.

Life with type 1 diabetes

Diabetes monitoring.
Health care professionals usually teach people with type 1 diabetes to self-manage the condition.

Type 1 diabetes always requires insulin treatment and an insulin pump or daily injections will be a lifelong requirement to keep blood sugar levels under control. The condition used to be known as insulin-dependent diabetes.3

After the diagnosis of type 1 diabetes, health care providers will help patients learn how to self-monitor via finger stick testing, the signs ofhypoglycemia, hyperglycemia and other diabetic complications. Most patients will also be taught how to adjust their insulin doses.

As with other forms of diabetes, nutrition and physical activity and exercise are important elements of the lifestyle management of the disease.

Video – type 1 diabetes overview

This video by ClearlyHealth looks takes a close look at type 1 diabetes, its causes, symptoms and diagnosis.

For more information on how type 1 and type 2 diabetes compare, read our article: the difference between type 1 and type 2 diabetes.