Type 2 Diabetes

Also known as: adult-onset diabetes and non-insulin dependent diabetes mellitus (NIDDM) (Note: These terms are now outdated).

Type 2 diabetes is the most prevalent form of the disease, accounting for 90 to 95% of all diabetes cases in America. Unlike type 1 diabetes, where destruction of the pancreas reduces and eventually stops the supply of the hormone insulin, people with type 2 diabetes are still able to produce insulin. However, the insulin they produce is unable to perform its primary job, which is helping the body's cells use glucose for energy. Usually this is due to a problem with the body's insulin receptors, the location on cells where insulin binds so that glucose can enter (although less frequently there may be a problem with the chemical makeup of the insulin itself). This condition is called insulin resistance.

If glucose can't be absorbed by the cells, it builds up in the bloodstream instead, and high blood sugar is the result. The pancreas keeps increasing insulin production in an effort to keep up with rising blood sugar levels, and high circulatin levels of insulin (known as hyperinsulinemia) develop. Hyperinsulinemia increases the risk of cardiovascular disease and other health problems.

Over time, the high blood glucose levels from uncontrolled diabetes can cause serious long-term health problems with virtually every system in your body. Eventually, they may cause damage to the insulin-producing beta cells of the pancreas, reducing insulin output. An early diagnosis is important to prevent some of the other more serious complications of diabetes, which include heart disease, high blood pressure, nerve damage, and kidney failure. Fortunately, in many cases type 2 diabetes can be adequately controlled through a combination of proper nutrition and exercise, which is usually the first line of treatment. However, some people with type 2 diabetes do require oral medications or insulin injections.

Although the vast majority of individuals with type 2 diabetes are adults, children and adolescents are increasingly at risk for the disease due to growing childhood weight problems and sedentary lifestyles.

What Causes Diabetes?

The exact causes of type 2 diabetes aren't completely understood, but it is known that the disease has a strong hereditary component. Individuals who have a parent or sibling with type 2 diabetes have 10 to 15% chance of developing the disease (the risk is much higher if the sibling is an identical twin).
Environmental factors like an inactive lifestyle or poor diet may act as a trigger for someone with a genetic tendency towards type 2 diabetes. Other potential causes of type 2 include chronic stress, low birth weight (and associated fetal malnourishment), and gene mutations. 1

Diabetes risk factors for developing type 2 diabetes include:

1. Overweight or obesity. Having a body mass index (BMI) of 25 or more
2. Heredity. Having a parent or sibling with type 2 diabetes
3. Ethnicity. Being of African American, American Indian, Asian American, Pacific Islander, or Hispanic American/Latino descent
4. Gestational diabetes. A history of gestational diabetes, or having at least one baby weighing more than 9 pounds at birth
5. Hypertension. High blood pressure of 140/90 mm Hg or higher
6. Poor cholesterol profile. HDL cholesterol ("good" cholesterol) levels of 35 or lower and/or triglyceride levels of 250 or higher
7. Inactivity. Living a sedentary lifestyle (i.e., exercising less than three times a week)
8. Being an older adult. Approximately 18.4% of Americans over age 65 have type 2 diabetes
9. Having diagnosed prediabetes

According to the National Institutes of Health, an estimated 80% of people with type 2 diabetes are overweight or obese (i.e., a BMI of 25 or higher). Here's why excess fat increases insulin resistance:

• Fat cells have fewer insulin receptors (the place where insulin binds to open the cell to glucose) than muscle cells.
• Fat cells release free fatty acids, and free fatty acids interfere with glucose metabolism.
• Excess glucose that can't be used by the cells for energy is stored as body fat, increasing the cellular mass that the pancreas is trying to "feed" via insulin. In overweight people, insulin production is increased to meet this mass increase.

References