A number of factors have been shown to increase the risk of developing type 2 diabetes. They include:

• Weight. Being overweight or obese is the leading risk factor for type 2 diabetes. Although it can occur in lean people (especially the elderly or people with a family history of the disease), about 80 percent of cases occur in people who are overweight. The more fatty tissue a person has, the more resistant the cells become to the individual’s own insulin.
  
  A healthy weight range can be determined by methods including a person’s body mass index (BMI). A person with a BMI of 25 to 29.9 is considered overweight. A person with a BMI of 30 or more is considered obese.
  
  The distribution of the weight is also a factor. People with excess weight above their hips, especially around their abdomen, are at a higher risk than those with excess weight on their hips and thighs.
  
  
• Activity level. The less physically active a person is, the greater the risk for type 2 diabetes because inactivity contributes to obesity, high blood pressure and unhealthy cholesterol levels. In addition, the body uses glucose for energy during exercise and helps to lower insulin resistance.
  
  
• Age. A person’s risk of developing type 2 diabetes increases with age. The disease is especially prevalent in those age 45 and over because people tend to exercise less, lose muscle mass and gain weight as they age. According to the American Diabetes Association (ADA), 20 percent of people over the age of 65 have type 2 diabetes.
  
  Although type 2 diabetes usually appears in middle-aged and older adults, it is increasingly being diagnosed in children and adolescents. The increase is most likely due to the rise in obesity, physical inactivity and poor eating habits in this population. When type 2 diabetes develops in children, it most often occurs during mid-puberty, a time when hormone levels are changing. These changes cause insulin resistance and decreased insulin secretion.
  
  
• Race/ethnicity and genetics. Type 2 diabetes is more common in African Americans, Hispanics/Latinos, Native Americans, Alaska Natives, Asian Americans and Pacific Islanders.
  
  Some researchers believe that these groups have inherited a “thrifty” gene that helped their ancestors survive during cycles of feast and famine. The gene enabled people to store energy in the body more efficiently during times when food was plentiful, in order to survive during times when food was scarce. This gene may be responsible for putting these groups at a higher risk of developing type 2 diabetes.
  
  The increased risk has also been attributed to changes in dietary practices, poverty, lack of access to health care, an increase in obesity and decrease in physical activity within these groups.
  
  Although type 2 diabetes is more common in some groups, the ADA does not consider race or ethnicity alone a statistically significant predictor of diabetes. Age, weight and activity level are more important factors.
  
  
• Family history. People’s risk of developing type 2 diabetes increases if their mother, father, sister or brother has the disease. The increase is most likely linked to the inheritance of certain genes.
  
  
• Sex. Though men make up less than half the U.S. adult population, they account for 53 percent of the adult cases of diabetes, according to the National Institutes of Health (NIH). The prevalence of diabetes in men and women was similar until 1999, when a growing disparity began, according to the U.S. Centers for Disease Control and Prevention (CDC). Little or no research has been conducted to account for the discrepancy.
  
  
• Prediabetes. People almost always have prediabetes before they develop type 2 diabetes.
  
  
• High blood pressure (hypertension). People with elevated blood pressure are at a greater risk of developing type 2 diabetes than those with normal blood pressure. Blood pressure above 140/90 millimeters of mercury (mm Hg) is considered high. 

• Unhealthy cholesterol levels. Patients with unhealthy cholesterol levels are at a greater risk of developing type 2 diabetes, and conversely those with type 2 diabetes are often found to have abnormally high lipid levels. High levels of triglycerides and low-density lipoprotein (LDL) cholesterol and low levels of high-density lipoprotein (HDL) cholesterol are considered unhealthy.
  
  
• Metabolic syndrome. This cluster of conditions can include prediabetes, abdominal obesity, high blood pressure and unhealthy levels of blood lipids.
  
  
• History of gestational diabetes. Women who develop this temporary form of diabetes during pregnancy are at a greater risk of developing type 2 diabetes later in life, particularly if they gain weight. The link may be related to the insulin resistance associated with both conditions.
  
  
• Giving birth to a baby weighing more than 9 pounds (macrosomia). Delivering at least one baby weighing more than 9 pounds is associated with an increased chance of the mother developing type 2 diabetes later in life. The oversized infant may also be increased risk.
  
  
• Low birth weight. Studies have shown that babies born weighing less than 5.5 pounds have a more difficult time processing glucose in their bodies than babies born at a normal weight. This may put people at an increased risk of type 2 diabetes later in life.
  
  
• • Acanthosis nigricans. This skin condition may appear in overweight people who are insulin resistant.
    
    
  • Polycystic ovarian syndrome (PCOS). This hormonal imbalance in females is linked to insulin resistance and type 2 diabetes.
    
    
• Smoking. People who smoke cigarettes are at a higher risk of developing type 2 diabetes than people who do not smoke.
  
  
• Exposure to Agent Orange. People who were exposed to the herbicide Agent Orange are at a greater risk for developing type 2 diabetes because there is an apparent connection between exposure and insulin resistance. In 2005, the U.S. Department of Defense finished analysis of its 20-year Air Force Health Study by concluding that type 2 diabetes was the most important health problem found in the crewmen who sprayed Agent Orange during the Vietnam War.
  
  
• Certain medications. Certain medications. Drugs that have linked to increased risk of diabetes include corticosteroids, some antihypertensives (beta blockers and diuretics), antidepressants, antipsychotics, antiretrovirals (HIV drugs), chemotherapy drugs and estrogens.
  
  
• Certain diseases. Some studies have linked conditions including fatty liver disease, gout, hemochromatosis, hepatitis C, pancreatitis and certain chromosomal and genetic disorders to increased risk of type 2 diabetes.

• Sleep irregularities. Some studies have linked insufficient sleep or excess sleep to increased risk of type 2 diabetes.

Over time, drinking large amounts of alcohol may increase a person’s risk of developing type 2 diabetes. However, some studies have shown that drinking a moderate amount of alcohol may reduce the odds of developing type 2 diabetes and other conditions such as heart disease. Patients are advised to ask their physician about the risks and benefits of moderate consumption of alcohol.