|
Definition, epidemiology, diagnosis and classification
Epidemiology
- Incidence studies most often define the onset of type 1 diabetes as the date of the first insulin injection, because of the variable time between onset of symptoms and diagnosis
- New case incidence varies greatly between different countries, within countries, and between different ethnic populations (Figure 1)
- In countries with higher incidence, the age of onset indicates that
- diabetes under the age of 1 year is extremely uncommon
- incidence increases with age
- there may be a minor peak at age 4–6 years
- there is a major peak at age 10–14 years
- In many countries the total incidence of type 1 diabetes has been shown to be increasing
|
- In some countries the incidence has also increased significantly in children under the age of 5 years
- There is no clear pattern of inheritance of childhood diabetes although there is familial aggregation due to the association of type 1 diabetes with certain genetic markers
- In the higher incidence countries the risks to relatives of developing the disease when a member of the family has type 1 diabetes, are as follows
- risk to child/adolescent of a father with type 1 diabetes ~7%
- risk to child/adolescent of a mother with type 1 diabetes ~2%
- risk to identical twin of a child with type 1 diabetes ~35%
- risk to sibling of a child with type 1 diabetes ~3–6%
|
|
|
|
|
|
