Type 1 diabetes
Type 1 diabetes is an autoimmune condition in which the immune system attacks the insulin-producing cells of the pancreas, so the body stops making enough insulin and needs insulin replacement for life.
Symptoms
- Increased thirst and frequent urination
- Unintended weight loss
- Fatigue
- Blurred vision
- In some cases, a rapid onset over days to weeks
Causes & risk factors
- An autoimmune process that destroys insulin-producing beta cells
- A family history of type 1 diabetes or other autoimmune conditions
- Most often diagnosed in children, teenagers, or young adults, though it can occur at any age
How it’s diagnosed
Diagnosis is based on blood glucose testing (including HbA1c) alongside the clinical picture; antibody testing can help distinguish type 1 from other forms of diabetes when the picture is unclear.
How it’s treated
Type 1 diabetes is managed with lifelong insulin therapy, individualized to each patient's routine, alongside blood glucose monitoring (including continuous glucose monitoring where appropriate) and regular follow-up.
When to seek care
- Very high thirst, urination, or unexplained weight loss
- Nausea, vomiting, abdominal pain, or fruity-smelling breath (possible diabetic ketoacidosis) — seek emergency care
- Blood glucose readings persistently outside the range agreed with your care team
FAQ
Is type 1 diabetes the same as type 2?
No. Type 1 is an autoimmune condition requiring insulin from diagnosis; type 2 usually involves insulin resistance and can sometimes be managed initially without insulin. See the type 2 diabetes page for details.
Can type 1 diabetes be prevented?
No prevention strategy is currently established for type 1 diabetes; it is not caused by diet or lifestyle.
Sources
- American Diabetes Association, Standards of Care in Diabetes—2026
- WHO diabetes fact sheets and IDF Diabetes Atlas
Medical disclaimer: Content on this page is for general education and is not a substitute for individualized medical advice, diagnosis, or treatment. Outcomes vary between patients. Boston Diabetes Center is outpatient / day-care specialty centre with an on-site diagnostic lab and pharmacy — no inpatient beds; imaging and inpatient care are coordinated through partner facilities.