"We really should stop thinking in terms of 'normal' and 'abnormal,' says endocrinologist Ronald Arky of Harvard Medical School. Arky is talking about blood sugar levels and how they are used as signs of diabetes risk. A new study indicates that risk begins to climb at levels that are lower than the standard cutoff between normal and elevated.

"That means it's better to think of these levels as a continuum of risk," not numbers that show either absolute safety or danger, Arky says, and even people previously considered normal should be told to keep their weight down and start exercising to ward off the disease.

The study, in this week's New England Journal of Medicine, was done among several thousand healthy young men, members of the Israeli Defense Forces. Their blood sugar was measured using a test called fasting blood glucose, and then the men were followed for nearly six years to see who developed diabetes. Men with a level between 95 and 99 ml/dl were almost three times as likely to get diabetes as were men with levels between 50 and 81. Men with levels around 90 had nearly twice the risk. What's particularly striking is that the standard definition of normal levels has been 100 or less. Yet here is clear evidence that risk starts going up even before 100.

"When people are in the range of the 90s, they should pay close attention to their weight, because more weight means even more risk, and they and their doctors should monitor their blood sugar closely," says Arky, who wrote a commentary on the study in the same issue of the Journal. "That's the best way to keep risk in check."