There are two main types of diabetes, known as Type 1 and Type 2. Type 1 diabetes is far more rare and results from the pancreas ceasing to function. Usually Type 1 diabetes will appear in a child by age 5, but in some cases it's onset can be delayed until adulthood. There is no "cure" for Type 1 diabetes, there is only treatment and management of the condition.
Type 2 diabetes on the other hand often does not appear until adulthood, most commonly in the 45 - 64 age demographic. For this reason, Type 2 diabetes was often referred to as "Adult-Onset diabetes," a term that is being used less now that Type 2 diabetes is on the rise in children and teens. Type 2 diabetes accounts for about 95% of all diabetes cases in the US.
So what exactly is Type 2 diabetes? What causes it and how can it be prevented or managed? Harvard Medical School lays it out very clearly in the article below.