You have just had the results of your annual physical and have been told that your fasting blood glucose has come back high, putting you at increased risk of type 2 diabetes. And if you are also overweight you know that your risk of developing diabetes is greatly increased. But if your weight and waist circumference are in the normal range you may think you have nothing to worry about.

Researchers followed nearly 1000 men and women for 9 years to see if those who gained weight or whose waist circumference increased over that period would be more likely to become diabetic. After adjustment for other risk factors at baseline, increases in both waist circumference and weight were individually found to be associated with increased incidence of diabetes.

The surprising thing was that the risk of becoming diabetic was greatest in those who had normal BMI* (>25 Kg/m²) at the start of the study. For them, an increase in BMI or waist size over the next few years increased the likelihood of becoming diabetic by nearly 80 percent. Note that a normal waist measurement in less than 35” for women and under 40” for men.

“It is important to monitor and prevent increases in waist circumference, in particular for those with BMI<25 kg/m²,” the study authors write.

* BMI is a measure of a person’s weight in relation to height, and you can calculate yours at many sites on the internet. A BMI of 19-25 is considered normal, 26-30 is considered overweight, and a BMI greater than 30 is obese. Waist measurement should be taken at or just below the belly button. Use a mirror or get someone to check that you keep the tape measure straight while measuring.

Reference:Increases in waist circumference and weight as predictors of type 2 diabetes in individuals with impaired fasting glucose: influence of baseline BMI: data from the DESIR study. Gautier Aet al. Diabetes Care. 2010 Aug;33(8):1850-2