.svg){kind=logo}
Differences between Type 1 Diabetes and Type 2 Diabetes?
Type 1 Diabetes can be mistaken for prediabetes
or Type 2 Diabetes, especially in adults1
Overview
Type 1 diabetes (T1D) and type 2 diabetes (T2D) are distinct conditions with different underlying causes. However, in adults, autoimmune T1D can sometimes be mistaken for prediabetes or T2D because early features may overlap.1,6 Understanding these differences can support appropriate clinical assessment.
Causes of Each Condition
Type 1 Diabetes
T1D is an autoimmune condition. This means the body’s immune system attacks the insulin‑producing cells in the pancreas.1,4,6
Because of this, the body gradually stops making insulin, and insulin treatment becomes necessary.
Type 2 Diabetes
T2D is not autoimmune. The body still makes insulin, but it may not use it properly (insulin resistance), or insulin levels may slowly decrease over time.
T2D is more common in adults and can be influenced by factors such as weight, age, and family history.1
Why T1D Can Be Mistaken For T2D In Adults.
Although T1D is common in children, adults can develop it too.4,7 In fact, many adults first diagnosed with T2D may actually have autoimmune T1D.1,4,6
This can happen because:
• Early features may look similar (e.g., high blood glucose).1,6
• Adults are often expected to have T2D, so autoimmune T1D may be overlooked.2,6
• Symptoms may appear more gradually in adults than in children.8
The Role of Autoantibody Testing
Autoantibody testing can help show whether diabetes is autoimmune.5
However, it is important to note:
- Autoantibody testing is mostly carried out in research studies or specialist clinics, not as part of routine NHS care.
- These tests can sometimes help clarify whether a person has autoimmune T1D or another form of diabetes.5
- Find Out More About Early Detection of T1D.
What is Autoimmune Type 1 Diabetes?
Am I or my family at risk?
Can T1D be detected early?
If you are concerned about diabetes or its symptoms, please speak to your healthcare professional
References
- American Diabetes Association. Diagnosis and Classification of Diabetes. Diabetes Care. 2025;48( 1):S27–S49.
- Holt RIG, et al. The management of Type 1 Diabetes in Adults. Diabetes Care 2021;44:2589-2625
- Insel RA, Dunne JL, Atkinson MA, etal. Diabetes Care. 2015;38(10):1964-1974.
- Thomas NJ, Jones SE, Weedon MN, et al. Frequency and phenotype of type 1 diabetes in the first six decades of life. Diabetologia. 2018;61:1081–1088.
- Winter WE, Pittman DL, Jialal I. Practical Clinical Applications of Islet Autoantibody Testing in Type 1 Diabetes. J Appl Lab Med. 2022;7(1):197-205.
- Thomas NJ, Lynam AL, Hill AV, et al. Type 1 diabetes defined by severe insulin deficiency occurs after 30 years of age and is commonly treated as type 2 diabetes. Diabetologia. 2019;62(7):1167-1172.
- Atkinson MA, Eisenbarth GS, Michels AW. Type 1 diabetes. Lancet. 2014;383(9911):69–82.
- Diabetes UK: Type 1 Diabetes Symptoms. Accessed May 2026