Cause of Type 2 Diabetes
Scientists are learning more and more about type 2 diabetes -- however, the exact cause of the disease is still unknown. However, there are several known risk factors that increase a person's chance of developing the disease. These include high blood pressure, abnormal lipid levels, lack of activity, family history, and ethnicity.
Type 2 diabetes was previously called noninsulin-dependent diabetes mellitus (NIDDM) or adult-onset diabetes. Type 2 diabetes accounts for about 90 percent to 95 percent of all diagnosed cases of diabetes.
Type 2 diabetes usually begins as insulin resistance, a disorder in which the cells do not use insulin properly. As the need for insulin rises, the pancreas gradually loses its ability to produce it.
Diabetes research scientists do not know why cells begin to no longer use insulin properly. They do, however, know a number of risk factors for developing type 2 diabetes.
While type 2 diabetes is not necessarily caused by risk factors, they do increase a person's chance of developing the disease. These risk factors include:
- Age. People over 45 years of age are at a higher risk for diabetes.
- Abnormal lipid levels. Men with an HDL cholesterol ("good cholesterol") of less than 40 mg/dL and women with an HDL cholesterol of less than 50 mg/dL are at increased risk for diabetes. People with triglyceride levels of 250 mg/dL or more are also at an increased risk for the disease.
- Being overweight. People who are overweight, which is defined as having a body mass index (BMI) greater than or equal to 25 (23 if Asian American; 26 if a Pacific Islander) are at higher risk of developing type 2 diabetes (see BMI Calculator).
- Family history. Statistics indicate that people with a parent or sibling with type 2 diabetes are at a higher-than-normal risk of getting the disease.
- Ethnicity. People of African American, American Indian, Asian American, Hispanic/Latino, or Pacific Island heritage have an increased risk of developing diabetes.
- Inactive lifestyle. People who exercise less than three times per week may be at an increased risk for type 2 diabetes.
- Blood pressure. People with blood pressure higher than 140/90 mm/Hg are at increased risk for diabetes (see High Blood Pressure).
- History of gestational diabetes. Women who have previously had gestational diabetes or given birth to at least one baby weighing 9 pounds or more are at increased risk for developing type 2 diabetes.
(Click Diabetes Prevention to learn more about these risk factors and ways to prevent type 2 diabetes.)