"People and physicians should not look only on the current definition of normal and abnormal blood glucose levels when assessing an individual’s risk to develop diabetes. A careful interpretation of the body mass index, the triglyceride level and the patient`s family history of diabetes is needed in order to better identify those at high risk," said Tirosh.

Normal fasting blood sugar levels are considered those that fall below 99 milligrams per deciliter (mg/dl) of blood, while anything between 100 and 125 mg/dl is considered pre-diabetic, according to the National Institute for Diabetes and Digestive and Kidney Diseases. Once fasting glucose levels rise to 126 mg/dl and above, a person is considered diabetic. Fasting glucose levels are taken after a person haven’t eaten for at least eight hours.

The new study suggests that more people may fall into the pre-diabetic category even if they have glucose levels at the high end of normal. One reason it’s important to identify people who are pre-diabetic is that they may be in poorer health than those who don’t have an impending risk of the disease. A study presented at the American Diabetes Association annual meeting in June found that people with pre-diabetes have health-care costs about one-third higher than those with normal blood sugar levels.
For the study, the researchers obtained fasting glucose levels for more than 13,000 men from the Israeli Defense Forces. All were between the ages of 26 and 45. The average follow-up time was 5.7 years. Among these men, 208 were diagnosed with type 2 diabetes during the study period.

Men who had fasting blood glucose levels at the high end of normal -- between 95 to 99 mg/dl -- had about three times the risk of developing type 2 diabetes as men with blood sugar levels under 81 mg/dl. Men who had additional risk factors and high-normal blood glucose readings were even more likely to develop type 2 diabetes. For example, obese men with fasting glucose levels between 91 and 99 mg/dl had eight times the risk of developing the disease, compared to non-obese men with blood glucose readings less than 86 mg/dl, the study found.

High triglyceride levels and a family history of the disease also increased the risk of diabetes for those with higher blood sugar levels.

Dr. Stuart Weiss, an endocrinologist at the New York University Medical Center, said, "This study may make people look more closely at patients who already have elevations, though modest, in blood sugar levels." "What we’ve learned over the past few years is that a rise in fasting sugar is seen well after insulin resistance has begun," he added.

A better measure of how well the body is processing glucose is to test blood sugar levels after meals, said Weiss. But this method is more time-consuming, and people need to use blood glucose monitors at home to get an average reading.

Source: Diabetes In Control