A new Centers for Disease Control and Prevention report finds that a staggering 30 million people—roughly 1 in 10 Americans—have type 2 diabetes. Most concerning: nearly a quarter of them don’t even realize it.

Just as worrisome is the prevalence of prediabetes: The new report reveals that 84 million adults, or roughly one-third of the U.S. population, have the elevated blood sugar levels that put them at high risk for developing full-blown diabetes.

"We’re not seeing the rate of diabetes and prediabetes growth continue to escalate in the way it has in previous years," says Ann Albright, Ph.D., R.D., director of CDC’s Division of Diabetes Translation. "Still the numbers of cases of undiagnosed prediabetes, in particular, are astounding. It’s evidence that more needs to be done to reach those at risk for type 2 diabetes.”

Type 2 diabetes is the 7th leading cause of death in the U.S., and the leading cause of disability. It is more common, though less severe, than type 1 diabetes. In both cases, the body doesn't produce enough insulin to regulate blood sugar levels properly, which can lead to serious medical issues such as heart and kidney disease. 

Here are some ways to reduce your risk of developing diabetes—and if you already have it, to prevent it from progressing.

Know Your Risk

A fundamental step in prevention, says Albright, is paying close attention and understanding your risk factors, including being 45 or older, overweight, and physically inactive; having a family history of diabetes or conditions such as high blood pressure, high cholesterol, or polycystic ovary syndrome; or having a history of gestational diabetes during pregnancy.

According to the CDC’s report, prevalence is higher among African Americans, Hispanics and Latinos, American Indians, and Asian Americans and Pacific Islanders; and, geographically speaking, Southern and Appalachian regions of the U.S. had the highest rates of diagnosed diabetes and of new cases.

If you’re not sure of your risk, the CDC recommends a two-stage approach. “First, everyone is encouraged to take an online risk test,” says Albright, such as the seven-question test at DoIHavePrediabetes.org. If it turns out you have a score that indicates an elevated risk, Albright recommends seeing your doctor for a blood test.

If You’re Inching Toward Diabetes

According to the CDC, prediabetes means your blood sugar levels are higher than normal but not high enough for a diagnosis of type 2 diabetes. A test of your average blood sugar reading over a three-month period will indicate that you have a hemoglobin A1C of 5.7 to 6.4 percent, or a fasting blood glucose level between 100 to 125 mg/dL.

Undetected or ignored, prediabetes can develop into diabetes within a few years. The good news is that if you have it, lifestyle changes such as a "proper eating plan that enables weight loss, and daily exercise, can work as well as or better than the use of medications," says Marvin M. Lipman, M.D., Consumer Reports' chief medical adviser.

In the landmark Diabetes Prevention Program (DPP) study, people with prediabetes who lost 7 percent of their body weight by eating less fat, consuming fewer calories, and exercising for 150 minutes per week had a 58 percent reduced risk of diabetes after three years. Participants taking metformin reduced their risk of developing diabetes by 31 percent.

And a 2015 a follow-up to the DPP study found that after 15 years, regular exercise plus a low-calorie, low-fat diet continued cutting the incidence of developing type 2 diabetes by 27 percent for people with prediabetes; metformin lowered it by 18 percent.

If You Already Have Type 2 Diabetes

There’s no cure for type 2 diabetes, although studies consistently show that lifestyle changes alone, especially weight loss in those who are overweight or obese, can go a long way in preventing complications such as heart disease, stroke, and eye, nerve, and kidney disease. For some people, lifestyle measures can even eliminate or reduce the need for drugs.

Still, for others, diet and exercise alone may not be enough. If your doctor determines you need medication, CR Best Buy Drugs still recommends starting with metformin (Glucophage and generic) and, if that doesn’t work, adding glipizide (Glucotrol and generic) or glimeride (Amaryl and generic). All of these medications are available as low-cost generics, costing between $3 and $15 for a month's supply at most pharmacies, according to price-comparison website GoodRx.com.

Keep in mind that type 2 diabetes medications can cause bothersome side effects, including ankle swelling, diarrhea, dizziness, tiredness, muscle pain, and, in rare cases, other symptoms caused by a dangerous buildup of lactic acid and a vitamin B12 deficiency.

Editor's Note: This article and related materials are made possible by a grant from the state Attorney General Consumer and Prescriber Education Grant Program, which is funded by the multistate settlement of consumer-fraud claims regarding the marketing of the prescription drug Neurontin (gabapentin).