Dear Savvy Senior: My brother and his wife, who are ages 60 and 56, were recently diagnosed with type 2 diabetes, and prediabetes, and neither one had a clue. Could I have it too? — Concerned Sibling

Dear Concerned: According to the Centers for Disease Control and Prevention nearly 115 million Americans have diabetes or prediabetes, but most of them don’t know.

Most people have prediabetes for a long time before the disease becomes type 2 diabetes, and even then it progresses gradually. That leaves a big window in which to stop, slow or reverse the disease.

Diabetes occurs when the pancreas doesn’t produce enough insulin to remove sugar from the bloodstream. Excess blood sugar damages blood vessels and affects circulation, putting you at risk for a host of ailments, from heart attack and stroke to blindness, kidney failure and nerve damage.

Are you at risk?

If you answer “yes” to any of the following questions, your odds of developing diabetes increases:

>> Are you over age 45?

>> Are you overweight?

>> Do you have high blood pressure – 140/90 or higher?

>> Do you have a parent or sibling with diabetes?

>> Are you sedentary?

>> Are you African American, Hispanic/Latino American, Native American, Asian American, Pacific Islander, or Alaska native?

>> Did you develop gestational diabetes during pregnancy?

To help you determine your risk of developing diabetes, take the free online quiz at Diabetes.org/risk-test.jsp.

Get tested

If you find that you’re at risk for diabetes, there are three diagnostic tests your doctor can give you. The most common is the “fasting plasma glucose test,” which requires an eight-hour fast. There’s also the “oral glucose tolerance test” to see how your body processes sugar, and the “hemoglobin A1C test” that measures your average blood sugar over the past three months. It can be taken anytime regardless of when you ate.

Most insurance plans and Medicare cover diabetes tests, however, if you’re reluctant to visit your doctor to get tested, you can buy a blood glucose meter at a drug store and test yourself at home.

Some top options, recommended by Consumer Reports, include FreeStyle Freedom Lite, Bayer Contour Next, True Metrix Blood Glucose Meter, OneTouch UltraMini, and the ReliOn (Wal-Mart) Micro, which all cost under $25.

If you find that you are prediabetic or diabetic, you need to see your doctor to develop a plan.

In many cases lifestyle changes like losing weight, exercising, eating a healthy diet and cutting back on carbohydrates may be all you need to do. For those who need more help, a doctor can prescribe medication.

Jim Miller is a contributor to NBCTV’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.