There are two main types of diabetes. Type 1 diabetes usually occurs during childhood or adolescence. Type 2 diabetes, which is the most common form of the disease, usually occurs in people who are 45 years of age or older.However, the rate of diagnosis of type 2 diabetes in children and adolescents is increasing.here are two main types of diabetes. Type 1 diabetes usually occurs during childhood or adolescence. Type 2 diabetes, which is the most common form of the disease, usually occurs in people who are 45 years of age or older.