Type 1 Diabetes
A lifelong condition where the body's immune system destroys the cells that make insulin, so blood sugar becomes too high. Insulin is needed every day.
Quick Summary
Extreme thirst, passing urine often, weight loss, tiredness and blurred vision, often developing over a few weeks.
Insulin injections or a pump every day, blood sugar monitoring, healthy eating and activity.
Family history and certain genes. It often starts in childhood or young adulthood but can occur at any age.
Overview
In type 1 diabetes, the immune system attacks the beta cells in the pancreas. Without insulin, sugar can't enter the cells and builds up in the blood.
It isn't caused by diet or lifestyle. With insulin and good management, people with type 1 diabetes can live full, active lives.
Symptoms
Thirst and frequent urination
Including bedwetting in children who were dry.
Weight loss and tiredness
Despite eating normally.
Blurred vision
From high blood sugar.
Diabetic ketoacidosis
Vomiting, tummy pain, deep breathing and drowsiness need emergency care.
Causes & Risk Factors
Biological Causes
An autoimmune reaction destroys insulin-making cells. Genes and possibly viral infections play a part.
Key Risk Factors
- Family history A parent or sibling with type 1 diabetes.
- Genes Certain HLA genes increase risk.
- Age Often diagnosed in children and young adults.
Management & Treatment
01. Insulin
Several injections a day or an insulin pump.
02. Monitoring
Checking blood sugar with a meter or a continuous glucose monitor.
03. Education
Learning to match insulin to food and activity and to manage low sugar.
Frequently Asked Questions
Can type 1 diabetes be prevented?
What is a hypo?
Can children with type 1 play sports?
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Diabetes Type 1(opens in a new tab) · MedlinePlus, US National Library of Medicine
- Type 1 diabetes(opens in a new tab) · NHS