Type 2 diabetes mellitus, more often known as type 2 diabetes, is the most common type of diabetes. Unlike in type 1 diabetes, people with type 2 diabetes may make healthy or even high levels of insulin. But, their body cells do not use insulin effectively. This resistance to insulin is often caused by obesity. Insulin is a hormone that helps control the level of glucose in the blood. Glucose is the main form of sugar in the body. When the body cannot control the level of glucose, it has a hard time converting food into the energy that the body needs to work. There are other forms of diabetes as well.
The pancreas, a long, thin organ located behind the stomach, makes insulin. In healthy people, the pancreas makes extra insulin when a person eats. Insulin moves glucose from the bloodstream into the body cells. The cells use glucose as their main energy source.
In a person with type 2 diabetes, however, even though the pancreas may make enough insulin, the body cells are resistant to the effects of insulin. So they don't receive enough glucose and the blood glucose level rises too high. This causes a condition called hyperglycemia, and it can cause damage to the body, if left untreated.
Obesity is the main cause of type 2 diabetes in both adults and children. A recent study showed a 33% increase in the number of Americans with type 2 diabetes during the past 8 years. The increase was 70% in people who were 30 to 39 years of age.
Type 2 diabetes accounts for about 90% to 95% of the cases of diabetes in the US. Type 2 diabetes used to be rare in children, but is now diagnosed in 20% of the children who have diabetes. Of the children diagnosed with type 2 diabetes, 85% are obese. At this time, most children diagnosed with type 2 diabetes are 10 years of age or older. Researchers believe there will be an increase in type 2 diabetes in younger children who become obese.
Type 2 diabetes is more common in people with a family history of the disease. It's also more common among African Americans, Hispanic Americans, Pacific Islanders, Asian Americans, and Native Americans.
Other risk factors for the development of type 2 diabetes include:
A recent study of 16,000 American women between the ages of 40 and 65 years showed that diabetes was listed as one of the top six diagnoses. A long-term study is under way to see if menopause and changes in hormone levels are factors in developing type 2 diabetes.
Almost all people who develop type 2 diabetes have a condition called prediabetes first. This condition used to be known as impaired glucose tolerance or impaired fasting glucose, and the ADA estimates that almost 16 million people over the age of 40 have it. This condition occurs when blood glucose levels are higher than healthy levels but too low to be diagnosed as diabetes. Without lifestyle changes, most people who have prediabetes will progress to type 2 diabetes within 10 years.