What is the difference between type 1 and type 2 diabetes?
Diabetes strikes when a person does not produce enough insulin. Insulin is required to move blood sugar (glucose) from the blood into the cells of the body, where it is broken down to create energy. If a person does not have enough insulin, then the glucose is stuck in the blood. This causes an elevated blood sugar level and leads to problems such as damage to the eyes, kidney, blood vessels, nerves and heart.
There are two entirely different mechanisms that can result in a person not producing enough insulin.
In type 1 diabetes, which was previously called juvenile diabetes, the body’s immune system, which is supposed to be fighting germs, starts to fight the factory that produces insulin: the beta cells in the pancreas. This destruction generally goes on for years with decreasing insulin production until a person reaches the point where insufficient insulin is produced to move sugar out of the blood.
This immune attack is not altered by eating sugar or gaining weight, so there is currently no proven way to avoid development of type 1 diabetes or to stop the process once it has started. This kind of diabetes requires insulin replacement through injections or an insulin pump, and no cure is yet available.
In type 2 diabetes, previously called adult-onset diabetes, the body can produce a lot of insulin but becomes partially blind, or resistant, to its presence. A person developing type 2 diabetes needs more and more insulin to trigger the process of moving sugar out of the blood. At some point, the person can no longer make enough insulin to meet the body’s needs and the blood-sugar level starts to rise.
There are several things that make a person resistant to insulin. Excess body weight and medications, such as some types of steroids, are the most common culprits. In this case, discontinuing the medication and/or losing weight can restore insulin sensitivity and the diabetes can actually go away. There are also some diabetes medications that make the body more sensitive to insulin, which can also reduce or eliminate the elevated blood-sugar level.
Type 1 diabetes has classically been thought to develop only in children, but in fact about half of patients with new cases of type 1 diabetes are adults. Although type 2 diabetes is traditionally thought to occur only in adults, the epidemic of childhood obesity means that at least 20% of adolescents with newly diagnosed diabetes actually have type 2 diabetes. Both types of diabetes do cause elevated blood sugar, which can be equally damaging to the body’s vital organs if not kept under careful control.
For more information about diabetes, visit uvahealth.com/services/diabetes-care.
Dr. David Repaske is chief of the Division of Pediatric Endocrinology at UVa Health.