In this article
Through decades of research, we know that type 1 diabetes (T1D) starts well before symptoms develop and diagnosis typically occurs.
We can use this knowledge to prevent people from developing serious illness at the point of diagnosis, improve their long-term health and investigate therapies which, in future, could stop T1D in its tracks.
Type 1 diabetes starts before you have any symptoms
Type 1 diabetes (T1D) doesn’t occur overnight – it develops gradually. This progression is categorised into the stages of T1D.
- Stages 1 and 2 T1D are referred to as ‘early-stage’, ‘pre-symptomatic’, or ‘pre-clinical’ T1D. They can be easily identified through screening tests.
- Stage 3 T1D is when diagnosis traditionally occurs, after people start showing the typical symptoms of the condition. These symptoms are the 4Ts: thirst, toilet (frequent urination), thinness and tiredness.
When does T1D start?
In the past, T1D was thought to start when people reached Stage 3 T1D, also known as ‘clinical’ T1D. But now researchers understand that some people are genetically susceptible to T1D. In those people, the condition starts when something in the environment triggers the immune attack on the insulin-producing beta cells in the pancreas.Â
The stages of T1D development
Type 1 diabetes stages: a timeline
No T1D
Healthy level of beta cells
Beta cells in the pancreas produce enough insulin to maintain normal blood glucose levels. No insulin injections are needed.
Triggering events
Body starts to attack beta cells
In people who are susceptible to the condition, environmental factors (such as viral infections) can trigger the immune system to attack beta cells. This produces autoantibodies (proteins the body makes against its own cells) that can be detected in the blood.
Stage 1
Pre-symptomatic T1D
2 or more autoantibodies are detected but blood glucose remains normal. Beta cells are gradually destroyed, but there are no symptoms. Screening can detect T1D at this stage.
Stage 2
Pre-symptomatic T1D
2 or more autoantibodies are detected. Beta cell loss continues and blood glucose becomes irregular, but symptoms are still absent. Screening can detect T1D at this stage.
Stage 3
Clinical T1D
Symptoms of T1D appear (the 4Ts: thirst, toilet, tiredness, thinness). Significant beta cell loss has occurred, insulin production is insufficient, and treatment with insulin begins.
Stage 4
Long-term T1D
The person has longstanding T1D after living with the condition for numerous years and is insulin dependent. Long-term health complications are common.
Detecting early-stage T1D
People in the early stages of T1D don’t experience any symptoms. But screening tests can detect the presence of immune markers of T1D in their blood.
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Breakthrough T1D aims to provide content that’s informative, easy to understand, and backed by research and credible sources.
Further reading
- Disease-Modifying Therapies in Type 1 Diabetes: A Look into the Future of Diabetes Practice
- Stages of Type 1 Diabetes and Mechanism of Action of Teplizumab
- Staging Presymptomatic Type 1 Diabetes: A Scientific Statement of JDRF, the Endocrine Society, and the American Diabetes Association
- T1Detect: Learn About Type 1 Diabetes Risk Screening
- Type1 Diabetes TrialNet