Dear Savvy Senior: What can you tell me about predia­betes, and how can you know whether you have it? My 62-year-old husband, who’s in pretty good shape, was recently diagnosed with prediabetes and didn’t have a clue. Could I have it, too? — Wondering Spouse

Dear Wondering: Underlying today’s growing epidemic of Type 2 diabetes is a much larger epidemic called prediabetes, which is when blood sugar levels are higher than they should be but not high enough to be called diabetes.

The Centers for Disease Control and Prevention estimates that as many as 84 million Americans today have prediabetes. Left untreated, it almost always turns into Type 2 diabetes within 10 years. And, if you have prediabetes, the long-term damage it can cause — especially to your heart and circulatory system — may already be starting.

But the good news is that prediabetes doesn’t mean that you’re destined for full-blown diabetes. Prediabetes can actually be reversed, and diabetes prevented, by making some simple lifestyle changes like losing weight, exercising, eating a healthy diet and cutting back on carbohydrates. Or, if you need more help, oral medications may also be an option.

Get tested

Because prediabetes typically causes no outward symptoms, most people who have it don’t realize it. The only way to know for sure whether you have it is to get a blood test.

Everyone age 45 years or older should consider getting tested for prediabetes, especially if you are overweight with a body mass index above 25. See CDC.gov/bmi to calculate your BMI.

If you are younger than 45 but are overweight or have high blood pressure, a family history of diabetes, or belong to an ethnic group (Latino, Asian, African or Native American) at high risk for diabetes, you should get checked, too.

To help you determine your risk of diabetes, the American Diabetes Association has a quick online risk test you can take for free at DoIHavePrediabetes.org.

Diabetes tests

If you find that you’re at risk for prediabetes, there are three different tests your doctor can give you to diagnose it.

The most common is the fasting plasma glucose test, which requires an eight-hour fast before you take it. There’s also the oral glucose tolerance test to see how your body processes sugar and the hemoglobin A1C test, which measures your average blood sugar over the past three months.

Most private health insurance plans and Medicare cover diabetes tests; however, if you’re reluctant to visit your doctor to get tested, an alternative is to go to the drugstore, buy a blood glucose meter and test yourself at home. Meters usually cost around $20.

If you find that you are prediabetic or diabetic, you need to see your doctor to develop a plan to get it under control. The ADA recommends losing weight and doing moderate exercise — such as 150 minutes a week of brisk walking.

When lifestyle changes alone don’t work, medication might. The ADA recommends the generic drug metformin, especially for very overweight people younger than 60.

For more information on diabetes and prediabetes or to find help, join a lifestyle change program recognized by the CDC (see CDC.gov/diabetes/prevention). These programs offer in-person and online classes in more than 1,500 locations throughout the U.S. Over the course of a year, a coach will help you eat healthy, increase your physical activity and develop new habits.

Jim Miller is a contributor to NBC-TV’s “Today” program and author of “The Savvy Senior.” Send your questions to Savvy Senior, P.O. Box 5443, Norman, OK 73070; or visit savvysenior.org.