Type 2 Diabetes Risk Factors

Unlike the situation for type 1 diabetes, researchers have identified many risk factors for type 2 diabetes.

Heredity

Family history plays an important role in type 2 diabetes. In a study of more than 200 adults with type 2 diabetes, about two thirds reported at least one close relative with diabetes and nearly 50 percent ad at least two relatives with the disease.

In particular, people whose mother had diabetes were twice as likely to get the disease as those whose father had diabetes—33 percent vs. 17 percent. Eleven percent of the women with type 2 diabetes had at least one child with diabetes, whereas only 4 percent of the men with type 2 diabetes had a child with the disorder.

Genes

In a very fast-moving field of research, investigators have discovered changes in at least 10 genes that can raise the risk of diabetes. All told, these known genetic variations may account for a roughly 2 to 20 percent greater overall chance for developing the disease. Researchers hope that by knowing who is at risk for diabetes, they can target ways to prevent or delay it. So far, however, there is no reliable test to tell if these genetic variations will substantially up your chances of suffering from diabetes down the road.

Race and ethnicity

Race and ethnic background affect diabetes risk. For example, African Americans, Hispanics, Asians, and Native Americans have a greater risk than whites of developing type 2 diabetes, although scientists aren't sure why this is so.

Obesity

Being overweight is the major contributing factor for type 2 diabetes. About 80 percent of individuals with type 2 diabetes are overweight or obese, and the risk of type 2 diabetes rises as a person's weight increases. Research suggests that having more fat cells somehow makes cells throughout the body more resistant to insulin.

Location of excess fat

Where your fat is located also makes a difference. People with abdominal obesity (excess fat within the abdomen) are more likely to develop type 2 diabetes than are those with extra weight in the hips and thighs. In fact, recent studies suggest that your waistline measurement is a better predictor of diabetes risk than your body weight.

The metabolic syndrome

Scientists have found that abdominal obesity is often accompanied by insulin resistance, increased blood glucose levels, high blood pressure (hypertension), low levels of high-density lipoprotein (HDL) cholesterol (the "good" cholesterol), and elevated triglycerides (another fat found in the bloodstream). This cluster of abnormalities, known as the metabolic syndrome, is an important risk factor not only for diabetes but also for heart disease and stroke.

Doctors are starting to pay more attention to the metabolic syndrome because its presence often suggests that diabetes is starting to develop. If you have a large waist circumference and unhealthy HDL and triglyceride levels, your doctor may order a test of your blood glucose levels after you have fasted for at least eight hours.

Prediabetes

Anyone with a fasting blood glucose reading of 100-125 mg/dL has prediabetes—blood glucose levels higher than normal but not high enough for a diagnosis of diabetes. About 54 million Americans have prediabetes. Without lifestyle changes or medication, many of them will develop type 2 diabetes within 10 years.

Physical inactivity

A sedentary lifestyle also is a risk factor for type 2 diabetes. Physical activity uses glucose, and thus less glucose accumulates in the bloodstream. Exercise also builds muscles, and muscle cells take up and use large amounts of glucose. If you get little exercise, however, you will have less muscle tissue, you will use less glucose, and blood levels of glucose will increase.

Aging

Getting older is another diabetes risk factor. Age alone does not seem to be the problem. Instead, it is what you're doing and what you're eating, particularly after age 45, that makes the difference. As people get older, they often exercise less, eat more foods that are high in fats and carbohydrates, and gain weight (especially around the middle).

Pregnancy

Some women develop type 2 diabetes during pregnancy (a condition called gestational diabetes). Although the diabetes goes away after childbirth, studies show that these women have an increased risk of developing diabetes later in life.

Other health problems

A small number of people are at risk for diabetes because they have diseases that destroy the pancreas, such as hemochromatosis (excessive absorption and storage of iron), chronic pancreatitis (inflammation of the pancreas), or pancreatic cancer. Certain tumors increase the risk of diabetes because they result in the overproduction of hormones that interfere with insulin action. For example, growth hormone produced by tumors of the pituitary gland, cortisol or epinephrine from adrenal tumors, and glucagon from pancreatic tumors can all raise blood glucose levels.

Medications

Certain medications increase the risk of type 2 diabetes in people who are predisposed to the disease. Examples are corticosteroids (commonly used to treat asthma and arthritis) and thiazide diuretics (typically used in the treatment of high blood pressure and heart failure).

Insomnia

Studies have shown that a lack of sleep can lead to insulin resistance and prediabetes, and may increase diabetes risk. Research also shows that people with diabetes have higher-than-normal rates of snoring and sleep apnea. The link between sleep and diabetes may be related to hormone levels. More research is needed.

Updated by Remedy Health Media

Publication Review By: Written by: Christopher D. Saudek, M.D.; Simeon Margolis, M.D., Ph.D.

Published: 21 Apr 2009

Last Modified: 29 Jan 2016