Home Diabetes Basics Overview Type 2

Type 2 Diabetes

type 2 diabetesThe most common form of diabetes is type 2 diabetes. About 90 to 95 percent of people with diabetes have type 2. This form of diabetes is associated with older age, obesity, family history of diabetes, previous history of gestational diabetes, physical inactivity, and ethnicity. About 80 percent of people with type 2 diabetes are overweight.

Type 2 diabetes is more common in older people, especially in people who are overweight, and occurs more often in African Americans, American Indians, some Asian Americans, Native Hawaiians and other Pacific Islander Americans, and Hispanic Americans. On average, non-Hispanic African Americans are 1.6 times as likely to have diabetes as non-Hispanic whites of the same age. Hispanic Americans are 1.5 times as likely to have diabetes as non-Hispanic whites of similar age. American Indians have one of the highest rates of diabetes in the world. On average, American Indians and Alaska Natives are 2.2 times as likely to have diabetes as non-Hispanic whites of similar age. Although prevalence data for diabetes among Asian Americans and Pacific Islanders are limited, some groups, such as Native Hawaiians and Japanese and Filipino residents of Hawaii aged 20 or older, are about twice as likely to have diabetes as white residents of Hawaii of similar age.

Type 2 diabetes is increasingly being diagnosed in children and adolescents. However, nationally representative data on prevalence of type 2 diabetes in youth are not available.

When type 2 diabetes is diagnosed, the pancreas is usually producing enough insulin, but for unknown reasons, the body cannot use the insulin effectively, a condition called insulin resistance. After several years, insulin production decreases. The result is the same as for type 1 diabetes—glucose builds up in the blood and the body cannot make efficient use of its main source of fuel.

People develop type 2 diabetes because the cells in the muscles, liver, and fat do not use insulin properly. Eventually, the pancreas cannot make enough insulin for the body’s needs. As a result, the amount of glucose in the blood increases while the cells are starved of energy. Over the years, high blood glucose damages nerves and blood vessels, leading to complications such as heart disease, stroke, blindness, kidney disease, nerve problems, gum infections, and amputation.

The symptoms of type 2 diabetes develop gradually. Their onset is not as sudden as in type 1 diabetes. Symptoms may include fatigue or nausea, frequent urination, unusual thirst, weight loss, blurred vision, frequent infections, and slow healing of wounds or sores. Some people have no symptoms.

Can type 2 diabetes be prevented?

Research has demonstrated that people at risk for type 2 diabetes can prevent or delay developing type 2 diabetes by losing a little weight. The results of the Diabetes Prevention Program (DPP) showed that moderate diet changes and exercise can delay and prevent type 2 diabetes. Participants in this federally funded study of 3,234 people at high risk for diabetes experienced a 5- to 7-percent weight loss. That’s 10 to 14 pounds for a 200-pound person.

Study participants were overweight and had higher than normal levels of blood glucose, a condition called pre-diabetes (impaired glucose tolerance). Both pre-diabetes and obesity are strong risk factors for type 2 diabetes. Because of the high risk for diabetes among some minority groups, about half of the DPP participants were African American, American Indian, Asian American, Pacific Islander, or Hispanic American/Latino.

DPP participants also included others at high risk for developing type 2 diabetes, such as women with a history of gestational diabetes and individuals aged 60 and older.

The DPP tested two approaches to preventing diabetes: a program of healthy eating and exercise (lifestyle change), and the diabetes drug metformin. People in the lifestyle change group exercised about 30 minutes a day 5 days a week, usually by walking, and lowered their intake of fat and calories. Those who took the diabetes drug metformin received information on exercise and diet. A third group only received information on exercise and diet.

The results showed that people in the lifestyle change group reduced their risk of getting type 2 diabetes by 58 percent. Average weight loss in the first year of the study was 15 pounds. Lifestyle change was even more effective in those 60 and older. They reduced their risk by 71 percent. People receiving metformin reduced their risk by 31 percent.