Type 2 Diabetes Causes

Some people have a genetic (inherited) predisposition to develop type 2 diabetes. Although genes influence the development of type 2 diabetes, people usually don't develop type 2 diabetes unless they have one or more risk factors.

The primary risk factors for type 2 diabetes are:

• Excess body weight (especially around the waist)
• High fat diet
• Inactivity

Additional risk factors include:

• Age greater than 45 years
• High-density lipoprotein (HDL) cholesterol less than 35 mg/dL
• History of gestational diabetes or high birth weight baby (over 9 pounds)
• Previously diagnosed impaired glucose tolerance
• Ethnicity (African Americans, Asian Americans, Hispanic/Latino Americans, Native Americans, and Pacific Islander Americans)
• Triglycerides greater than 150 mg/dL

Insulin's Role

During digestion, the carbohydrates in food are broken down into glucose (and a few other simple sugars), which enters the bloodstream. Insulin produced by the pancreas enables the body's cells to absorb the glucose and convert it into energy. Any excess glucose is stored in the liver as glycogen and released back into the bloodstream when the body needs additional glucose. Various factors increase the body's need for glucose, such as exercise, infection, or injury.

Type 2 diabetes usually develops when people become resistant to insulin. Insulin resistance reduces the body's normal response to insulin. The body's cells (fat, muscle, and liver) are unable to use insulin properly and require increased insulin levels to absorb the glucose in the blood.

The pancreas responds by producing more insulin. Eventually, the pancreas cannot produce enough insulin and the cells cannot absorb enough glucose to meet the energy demands of the body.

At first, insulin resistance has no symptoms. If left untreated, blood sugar levels rise and people may start experiencing the symptoms of type 2 diabetes.