At what age is Type 1 diabetes most likely to be diagnosed?

Type 1 diabetes is most commonly diagnosed during infancy or childhood, which is why this answer is correct. This form of diabetes primarily develops due to an autoimmune response that destroys the insulin-producing beta cells in the pancreas. While it can occur at any age, the majority of cases are diagnosed before the age of 18, particularly in young children and adolescents. The peak onset age is typically around 5 to 7 years and again around 11 to 13 years.

The other choices reflect age groups where Type 1 diabetes is less prevalent. Adulthood and middle age are more commonly associated with Type 2 diabetes, which results from insulin resistance rather than an autoimmune process. While late teens can be a time for the diagnosis of Type 1 diabetes, it is still more frequently diagnosed in younger children. Thus, identifying that Type 1 diabetes is predominantly diagnosed in the early years of life underscores why the correct choice is during infancy or childhood.