At what age does type 1 diabetes typically start and at what age is type 2 diabetes considered?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: June 22, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

Type 1 diabetes typically starts in childhood or adolescence, with most cases diagnosed before age 18, though it can develop at any age, while type 2 diabetes is generally considered an adult-onset condition, typically developing after age 10 in children with overweight or obesity and additional risk factors, as stated in the most recent guidelines 1. The distinction between type 1 and type 2 diabetes is crucial for appropriate treatment planning, and the increasing overlap in age of onset means that proper diagnostic testing is essential. Some key points to consider include:

  • The prevalence of type 2 diabetes in youth has continued to increase over the past 20 years, with a significant impact on historically marginalized communities 1.
  • Risk-based screening for prediabetes and/or type 2 diabetes should be considered after the onset of puberty or at age 10, whichever occurs earlier, in youth with overweight or obesity and additional risk factors 1.
  • The presence of islet autoantibodies has been associated with faster progression to insulin deficiency, and obesity contributes to the development of type 1 diabetes in some individuals, further complicating the diagnostic challenges 1.
  • Accurate diagnosis is critical, as treatment regimens, educational approaches, dietary advice, and outcomes differ markedly between patients with type 1 and type 2 diabetes 1. Given the complexity of diagnosing and managing diabetes in children and adolescents, a multidisciplinary team of specialists trained in pediatric diabetes management should provide care for this population, with a focus on diabetes self-management education, medical nutrition therapy, and psychosocial support 1.

From the Research

Type 1 Diabetes Onset Age

  • Type 1 diabetes can occur at any age, but it is typically considered a disease of children and young adults 2
  • The frequency of type 1 diabetes is higher in individuals diagnosed at a younger age, but it can also occur in adults, with 42% of genetically defined type 1 diabetes cases occurring in individuals diagnosed between 31-60 years old 2
  • Diabetic ketoacidosis at diagnosis is more common among those with onset in childhood, while participants diagnosed as adults are more likely to be overweight/obese at diagnosis and to have used oral agents preceding type 1 diabetes diagnosis 3

Type 2 Diabetes Onset Age

  • Type 2 diabetes is often considered a disease of adults, but it can also occur in children and adolescents 4
  • The prevalence of complications and comorbidities is higher among teenagers and young adults with type 2 diabetes compared to those with type 1 diabetes 4
  • Type 2 diabetes can occur at any age, but the risk of developing the disease increases with age, with most cases occurring in individuals over 40 years old 5

Comparison of Type 1 and Type 2 Diabetes

  • Type 1 diabetes is characterized by insulin dependence, while type 2 diabetes is often characterized by insulin resistance and impaired insulin secretion 2
  • The clinical characteristics of type 1 diabetes differ from those of type 2 diabetes, with type 1 diabetes often presenting with diabetic ketoacidosis, lower BMI, and higher rates of insulin use 2
  • The distinction between type 1 and type 2 diabetes can be difficult to make, especially in adults, and requires careful consideration of clinical characteristics, genetic susceptibility, and other factors 3, 2

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.