Type 1 diabetes

Synonyms: Insulin-dependent diabetes, Diabetes mellitus type 1, Juvenile diabetes, Type 1 DM or T1D

Medical Specialties: Endocrinology, Family practice, Pediatrics

Clinical Definition

Type 1 diabetes is an endocrine-based disease that occurs when the human pancreas produces insufficient amounts of insulin, or none at all. The result is a buildup of abnormally high levels of sugar (i.e., glucose) in the blood. 

In Our Own Words

Type 1 diabetes (formerly juvenile diabetes) is a disease of the endocrine system in which the insulin-producing cells of the pancreas (i.e., beta cells) are not working. Insulin is a hormone that helps the body process sugar for energy, while diabetes prevents the body from processing energy from food. The blood sugar or glucose levels then become elevated, and people who suffer from type 1 diabetes require insulin injections to regulate their blood sugar.


In children, type 1 is actually the most common form of diabetes, while in the general population, type 2 diabetes is much more prevalent. Historically, type 1 diabetes was called juvenile diabetes, owing to a typically earlier age of onset as compared with type 2. The term juvenile diabetes is still used in some settings to mean type 1.

Relevant Conditions
  • Diabetic ketoacidosis
  • Diabetic retinopathy
  • Diabetic nephropathy
Side Effects
  • Weakness and fatigue
  • Unexplained weight loss
  • Excessive thirst and dry mouth
  • Sores or cuts that are slow to heal
  • Itchiness in the groin or vaginal area
Share this article
  • Cleveland Clinic. “Diabetes.” Updated January 2013. http://my.clevelandclinic.org. Accessed August 2013.
  • MedlinePlus. “Diabetes Type 1.” Updated December 2013. http://www.nlm.nih.gov. Accessed January 2014.
  • Harvard Health Publications. “Medical Dictionary of Health Terms.” http://www.health.harvard.edu. Accessed August 2013.
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