In every issue of WebMD the Magazine, we ask our experts to answer readers' questions about a wide range of topics. In our January-February 2011 issue, we asked WebMD's diabetes expert, Michael Dansinger, MD, to answer a question about the link between prediabetes and diabetes.
Q: At my last checkup, my doctor told me I have prediabetes. Does that mean I'll ultimately develop diabetes?
A: Almost everyone who develops type 2 diabetes develops prediabetes first. But not everyone who has prediabetes...
A normal sugar level is less than 100 mg/dL after not eating (fasting) for at least 8 hours. And it's less than 140 mg/dL 2 hours after eating.
During the day, levels tend to be at their lowest just before meals. For most people without diabetes, blood sugar levels before meals hover around 70 to 80 mg/dL. For some people, 60 is normal; for others, 90.
What's a low sugar level? It varies widely, too. Many people's sugar levels won't ever fall below 60, even with prolonged fasting. When you diet or fast, the liver keeps sugar levels normal by turning fat and muscle into sugar. A few people's levels may fall somewhat lower.
Doctors use these tests to find out if you have diabetes:
Fasting plasma glucose test. The doctor tests your blood sugar level after fasting for 8 hours and it’s higher than 126 mg/dL.
Oral glucose tolerance test. After fasting for 8 hours, you get a special sugary drink. Two hours later your sugar level is higher than 200.
Random check. The doctor tests your blood sugar and it’s higher than 200, plus you’re peeing more, always thirsty, and you’ve gained or lost a significant amount of weight. He’ll then do a fasting sugar level test or an oral glucose tolerance test to confirm the diagnosis.
Any sugar levels higher than normal are unhealthy. A level that's higher than normal, but not reaching the point of full-blown diabetes, is called prediabetes.
According to the American Diabetes Association, 86 million people in the U.S. have prediabetes. These people are five to six times more likely to get diabetes over time. Prediabetes also raises the risk for cardiovascular disease, although not as much as diabetes does. It's possible to prevent the progression of prediabetes to diabetes with diet and exercise.