Type 2 diabetes can run in families. Certain factors increase your family members' risk for developing diabetes, including:

• Being overweight. The risk for type 2 diabetes increases with weight gain (increasing body mass index, or BMI), especially a gain of more than 22lb after age 18 in women or 18lb after age 21 in men. Having a large amount of fat in the abdominal area also increases the risk.¹ To determine BMI, see the charts:
  • Body mass index (BMI) for adults or body mass index (BMI) for adults (metric).
  • BMI chart for boys or the BMI chart for girls. Children who are in the 85th percentile or above for their age have a risk of developing type 2 diabetes in childhood.
• Lack of exercise. Participating in physical activity less than once a week increases a person's chance of developing type 2 diabetes by 20% to 40%.¹ One large study found that women who were sedentary, especially those who watched a lot of television, were at higher-than-average risk for obesity and type 2 diabetes.²
• Having prediabetes, or impaired glucose tolerance. In the United States, 41 million people between the ages of 40 and 74 have prediabetes and are at risk for developing type 2 diabetes.³ A large, long-term study showed that a nutritious diet and regular exercise can prevent type 2 diabetes. Lifestyle changes reduced the risk by 58% overall and by 71% in people older than 60.⁴

For a complete list of risk factors for type 2 diabetes, see the What Increases Your Risk section of the topic Type 2 Diabetes.