Overweight (BMI level > or =25 kg/m2) and in particular high abdominal fat levels (waist circumference > or =88 cm in women and > or =102 cm in men), are among the main risk factors for the development of type 2 diabetes mellitus. Results from the Hoorn Study show that 16.3% of overweight participants with high abdominal fat levels developed diabetes within 6 years, compared with 6.8% of those who were not overweight and had low abdominal fat levels. Information on overweight and abdominal fat level is not enough to properly estimate the risk of type 2 diabetes in an individual patient. The combination of information on overweight with information on other important risk factors for diabetes, such as family history, age, blood pressure and elevated blood glucose levels in the form of a calculated diabetes risk score, gives a better estimate of the individual diabetes risk.