Although there are many different types of Diabetes, the most common types of diabetes are type 1, type 2, and gestational diabetes.
Type 1 diabetes
Type 1 Diabetes usually affects children and young adults, although it can occur at any age. Pancreas of people with Type 1 Diabetes do not make any insulin at all. This is thought to be an autoimmune disease, which means that some antibodies (molecules originally designed to fight germs and prevent from infections) turn against own body cells. In case of Type 1 Diabetes, these antibodies act against the pancreatic Beta Cells, which are responsible for producing insulin. Since people who have Type 1 Diabetes, do not have any insulin production in the body, they need to have insulin from outside to stay alive. Oral drugs which are effective in Type 2 Diabetes are generally not effective in Type 1 Diabetes.
Type 2 diabetes
Type 2 diabetes is the most common type of diabetes. It usually develops in the people aged > 30 years, but can develop at any age. People with Type 2 diabetes initially have enough or even higher levels of insulin in their body, but the insulin can not act effectively at the cellular level. Later in the course of disease, when pancreas get exhausted of the insulin, the insulin levels may be low, and such patients may also require insulin for proper control of blood sugar levels.
As the name suggests, Gestational diabetes develops in some women when they are pregnant. Most of the time, this type of diabetes goes away after the baby is born. However, women with gestational diabetes have a greater chance of developing type 2 diabetes later in life. Sometimes diabetes diagnosed during pregnancy is actually type 2 diabetes.
Other types of diabetes
Less common types include pancreatic diabetes, which occurs due to diseases of pancreas, monogenic diabetes, which is an inherited form of diabetes, and cystic fibrosis-related diabetes, etc.