Type 1 diabetes occurs because the insulin-producing cells of the pancreas are damaged; they produce little or no insulin. People with Type 1 diabetes must use insulin injections to control their blood glucose. The damage to the insulin-producing cells in Type 1 diabetes occurs over a period of years. However, the symptoms of Type 1 diabetes may occur over a period of days to weeks. Type 1 diabetes most commonly starts in people under the age of 20, but may occur at any age.
Unlike people with Type 1 diabetes, people with Type 2 diabetes produce insulin. However, the insulin they produce is either not enough or doesn't work properly in the body. When there isn't enough insulin or the insulin is not used as it should be, glucose can't get into the body's cells. Type 2 diabetes is the most common form of diabetes mellitus, affecting almost 17 million Americans. While over 91% of these cases can be prevented, it remains for adults the leading cause of related complications such as blindness, non-traumatic amputations and chronic kidney failure requiring dialysis. Type 2 diabetes usually starts in people over age 40 who are overweight but can occur in people who are not overweight. It is sometimes referred to as "adult-onset diabetes.' Some people can manage their Type 2 diabetes by controlling their weight, watching their diet, and exercising regularly. Other may also need to take a pill that helps their body use insulin better, or take insulin injections.
Gestational diabetes is triggered by pregnancy. Hormone changes during pregnancy can affect insulin's ability to work properly, resulting in high blood glucose levels. Pregnant women who have an increased risk of developing gestational diabetes are those who are over 25 years old, are above their normal body weight before pregnancy, have a family history of diabetes or are Hispanic, black, Native American, or Asian. Usually, blood glucose levels return to normal after childbirth. However, women who have had gestational diabetes have an increased risk of developing Type 2 diabetes later in life.