Prediabetes

Prediabetes can be a warning sign of type 2 diabetes. Learn prediabetes causes and symptoms, plus how to lower blood sugar and reduce your risk of diabetes.

Introduction

More than one in three adults in the United States has prediabetes. This condition is marked by blood sugar levels that are higher than normal. If blood sugar levels continue to rise, prediabetes can turn into type 2 diabetes. Taking steps to lower your blood sugar levels can help reverse prediabetes and boost your overall health. 

Learn the facts about prediabetes, including what causes the condition and its signs and symptoms. Discover how you can take action to lower your blood sugar levels and stop or delay prediabetes from progressing to diabetes.

What is prediabetes?

Having prediabetes means your blood sugar (also called blood glucose) levels are elevated, although they’re not yet high enough to be considered type 2 diabetes. Blood sugar comes from the foods and beverages you eat. Glucose provides your body with energy and is necessary for body functions, but too much sugar in the blood can damage the heart, blood vessels, kidneys, and other organs over time.

In addition to potentially leading to type 2 diabetes, prediabetes increases your risk of stroke, heart disease, and kidney disease. The good news is that making healthy lifestyle changes can lower blood sugar levels and treat prediabetes in many cases.

What is insulin resistance?

Insulin resistance is a major cause of both prediabetes and diabetes. Insulin is a hormone produced by the pancreas, a small, pear-shaped gland located behind the stomach. The hormone assists in regulating blood sugar levels when you eat or drink. It helps your body’s cells use blood sugar to generate energy.

Having insulin resistance means your body’s cells have trouble using insulin properly, which can result in a buildup of sugar in the blood, leading to prediabetes.

How common is prediabetes?

Prediabetes is very common in the U.S. More than 97.6 million people ages 18 and older have the condition, according to the Centers for Disease Control and Prevention (CDC). That’s 38 percent of the adult population. Among people ages 65 and older, nearly 49 percent have prediabetes. Signs of the condition can be subtle, though, and more than 80 percent of people with prediabetes are unaware they have it, according to the CDC.   

Prediabetes is also common in children and teenagers thanks in part to a steep rise in childhood obesity over the past few decades. A 2022 study published in JAMA Pediatrics found that close to 1 in 3 adolescents between the ages of 12 and 19 in the U.S. has prediabetes. Rates among this age group jumped from 11.6 percent to more than 28 percent, based on data collected in 1999 to 2000 and then again in 2015 to 2018.

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What are the signs and symptoms of prediabetes?

Woman with prediabetes lying in bed during the day feeling fatigued

Most people with prediabetes don’t experience any noticeable signs or symptoms. But in some cases, prediabetes may cause:

  • Patches of darkened skin on the underarms, groin area, or back or sides of the neck
  • Changes in vision, including blurry vision
  • Skin tags (small skin growths)

Prediabetes that has advanced to type 2 diabetes may cause symptoms such as:  

  • Fatigue  
  • Increased thirst
  • Frequent urination
  • Reduced vision
  • Increased appetite
  • Unexplained weight loss
  • Tingling sensations or numbness in the hands or feet  
  • Sores that won’t heal

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What causes prediabetes?

The primary cause of prediabetes is insulin resistance. When you eat or drink, your pancreas secretes extra insulin to help your cells take in and use sugar as fuel. When your body’s cells become resistant to insulin, they don’t respond well to the hormone and they have a harder time processing sugar properly. This can cause sugar to accumulate in blood.

Prediabetes can also occur if your pancreas doesn’t produce enough insulin to keep blood sugar levels under control. That excess sugar in the blood can eventually lead to heart disease and kidney disease, among other issues.

There are a handful of factors that can cause or contribute to insulin resistance, including:

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What are the risk factors for prediabetes?

Prediabetes is a widespread issue that can affect people of all ages and backgrounds. Still, certain factors are linked with a higher risk of developing the condition.  

Risk factors for prediabetes include:

  • Being 45 or older
  • Being overweight or obese. (The risk of insulin resistance and prediabetes increases for people assigned female at birth with waist measurements larger than 35 inches and for people assigned male at birth with waists larger than 40 inches around.)
  • Having certain medical issues, including high blood pressure (hypertension), polycystic ovary syndrome (PCOS), low levels of HDL (aka “good” cholesterol), or high levels of triglycerides (a type of fat in the blood)
  • Experiencing diabetes during pregnancy (called gestational diabetes) or giving birth to a baby weighing more than 9 pounds
  • Having a first-degree relative (such as a parent or sibling) with type 2 diabetes
  • Living a sedentary lifestyle or exercising less than three times per week  
  • Having a history of stroke or heart disease
  • Being of African American, Latin American, Native American, or Asian/Pacific Islander descent  
  • Smoking cigarettes

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When should you be screened for prediabetes?

Testing for prediabetes is typically recommended for everyone ages 35 and older, but people with multiple risk factors for prediabetes or diabetes should consider starting screening at a younger age. The American Diabetes Association encourages prediabetes screening for children, teens, and adults who are overweight and have at least one other risk factor for type 2 diabetes, such as: 

  • Being of African American, Native American, Latin American, or Asian/Pacific Islander descent   
  • Having a family history of type 2 diabetes 
  • Having a personal history of heart disease
  • Having high blood pressure (higher than 130/80 mm Hg) or taking medication for high blood pressure

Additional prediabetes risk factors in children include being of low weight at birth and having a mother who experienced gestational diabetes.

You should also promptly speak with an HCP if you develop possible symptoms of prediabetes or diabetes, such as areas of darkened skin, blurry vision, or increased thirst or urination.  

Regularly visiting your HCP for routine preventive care can help uncover prediabetes and other health concerns before they cause noticeable symptoms or problems. A preventive care visit (or “checkup”) may involve:

  • A physical exam 
  • Screening tests for prediabetes and other common medical concerns, such as high blood pressure
  • Vaccines for preventable diseases like the flu or pneumonia
  • Determination of an appropriate cancer screening schedule based on your risk factors
  • Education to help you make confident decisions about your health

People who are younger than 50 and in good overall health are generally advised to visit an HCP at least once every three years for preventive care. (Everyone age 40 and older should have their blood pressure checked every year. You can do so for free at workplace or community health fairs or at most pharmacies. You can also use an at-home blood pressure monitor). People age 50 and older who are in good health should see an HCP at least once every year.  

Your HCP can recommend an ideal schedule of preventive care based on your age, overall health, and risk factors for conditions like diabetes and heart disease.

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How is prediabetes diagnosed?

Prediabetic woman doing a finger prick to measure haemoglobin A1C blood glucose levels, using smart phone app

An HCP can measure your blood sugar levels and rule out or diagnose prediabetes by ordering a simple blood test. The most common tests for prediabetes include:  

Fasting plasma glucose test

A fasting plasma glucose (FPG) test measures how much sugar is in your blood after not eating or drinking for at least eight hours (or overnight). It’s typically a part of routine blood tests that an HCP may perform to learn more about your health.

Results of an FPG test are provided in milligrams of sugar per deciliter (mg/dL):

  • Normal: 99 mg/dL or lower 
  • Prediabetes: 100 to 125 mg/dL
  • Diabetes: 126 mg/dL or higher

A1C test

An HCP may also want to perform an A1C test (also called a glycated hemoglobin test). This assesses your blood sugar levels over the previous three months. Results are given as a percentage:

  • Normal: 5.6 percent or lower
  • Prediabetes: 5.7 to 6.4 percent
  • Diabetes: 6.5 percent or higher   

Oral glucose tolerance test

An oral glucose test involves drinking a sugary beverage at the HCP’s office or testing site after fasting overnight. Your blood sugar levels are then checked several times over the next few hours.

When blood sugar levels are measured at two hours, the results of oral glucose tolerance testing indicate the following:

  • Normal: 139 mg/dL or lower
  • Prediabetes: 140 to 199 mg/dL
  • Diabetes: 200 mg/dL or higher

An oral glucose tolerance test is often performed in pregnant people since pregnancy can interfere with the results of A1C testing. An HCP can make a diagnosis of gestational diabetes based on blood glucose results after one to three hours.

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What questions should you ask a healthcare provider?

If you’ve been diagnosed with prediabetes, don’t shy away from asking questions about your condition. Learning about prediabetes and how it affects your health can help you make confident decisions about your care.

A few basic questions to get you started include:  

  • Is my prediabetes reversible?  
  • What do you think caused my prediabetes?
  • How do I prevent prediabetes from turning into diabetes?
  • What changes should I make to my diet? What foods and beverages should I add, limit, or avoid? 
  • Should I consult with a dietitian? 
  • Do I need to lose weight? What is a healthy body weight for my height and age?
  • How often should I exercise? What exercises would you recommend for me?
  • What are my treatment options? Do I need to take medication? 
  • How can I best manage prediabetes with my other health conditions?
  • What are signs that my prediabetes has turned into diabetes? 
  • When should I contact you? Is there a scenario in which I should seek emergency care?
  • Can you refer me to a local or online diabetes prevention program or support group?

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How is prediabetes treated?

Prediabetes treatment focuses on lowering blood sugar levels and preventing or delaying the onset of type 2 diabetes. With appropriate treatment, prediabetes is often reversible. Your primary HCP may provide prediabetes treatment or they may refer you to an endocrinologist (a medical doctor who specializes in hormonal and metabolic disorders like diabetes).

Diet and lifestyle changes for prediabetes

Making healthy diet and lifestyle changes is the main treatment for prediabetes and the best way to prevent diabetes for most people. With an HCP’s guidance, try to:  

Reach and maintain a healthy body weight

Losing excess body fat and reaching a healthy weight through diet and exercise can help reverse prediabetes and keep diabetes (and other health concerns) at bay. In fact, research shows that losing 7 percent of your body weight (or around 15 pounds if you weigh 200 pounds) can lower your risk of type 2 diabetes by as much as 58 percent.  

Your HCP can help determine a realistic and healthy weight goal based on factors like your height, age, and lifestyle. Don’t get discouraged if you have trouble reaching this number; losing just 10 pounds can provide health benefits for many people.

Adjust your diet

Filling your plate with more vegetables, whole grains, nuts, lean proteins, and healthy fats like olive oil can help satisfy your appetite without causing your blood sugar levels to spike. You may want to speak with your HCP about trying the Mediterranean diet, which can help regulate blood sugar levels and lower your risk for type 2 diabetes. Some foods on the eating plan can be expensive, but there are ways to incorporate some of features of the Mediterranean eating style while sticking to a budget.

It’s also important to limit or avoid sugar-sweetened beverages and foods with added sugars, such as candies, cookies, cakes, muffins, many breakfast cereals, and granola bars. Swapping out simple carbohydrates (carbs) for complex carbohydrates is also beneficial if you have prediabetes. Simple carbs are digested quickly and can cause blood sugar levels to rise rapidly. Complex carbs are digested slowly and only raise blood sugar levels moderately.

Some simple carbs to avoid include:

  • White or brown sugar  
  • Honey
  • White pasta, rice, and bread
  • Molasses
  • Syrup
  • Sweetened soda  

These complex carbohydrates can still satisfy your appetite for carbs while helping maintain steady blood sugar levels:

  • Sweet potatoes and other starchy vegetables
  • Legumes such as lentils, chickpeas, and peanuts
  • Whole-grain pasta, rice, and bread
  • Fruits like berries, peaches, apples, and oranges   

Some people with prediabetes benefit from working with dietitians or nutritionists who can provide expert guidance on smart eating habits. Your HCP may be able to refer you to a professional they know and recommend.

Get moving

Engaging in regular physical activity is a key part of managing and treating prediabetes. Not only can exercise help you lose excess weight, it can significantly improve how well your body uses insulin and converts sugar into energy.

The CDC advises adults with (or without) prediabetes to aim for 150 minutes of moderate-intensity aerobic exercise every week. This equates to 30 minutes of exercise five days per week. Examples of moderate-intensity aerobic exercise include brisk walking, doing water aerobics, playing doubles tennis, and even pushing a lawn mower.

If you’d prefer to pick up the pace, another option is to do 75 minutes of vigorous-intensity aerobic exercise per week. These activities include jogging, swimming laps, playing basketball or singles tennis, or riding a bicycle at a fast pace. It’s also a good idea to mix in two days of muscle-strengthening activities per week, such as lifting light weights, using resistance bands, or doing body-weight exercises like sit-ups and planks.   

The CDC recommends that children and adolescents ages 6 through 17 years get around 60 minutes of physical activity every day. This can be anything that gets their hearts beating faster, from walking and running to playing tag, scaling the monkey bars, playing basketball or soccer, or riding a bike.

Before embarking on a new exercise regimen, be sure to check with your HCP. Some types of physical activity aren’t recommended for people with chronic conditions like heart or lung disease. Your HCP may refer you to a fitness trainer or an exercise physiologist for further guidance.

Implement other healthy habits

Relatively small actions can make a big difference when it comes to managing prediabetes. In addition to diet and exercise, other habits that can help prevent diabetes and improve your well-being include:

  • Quitting smoking
  • Treating or staying on top of other health conditions you may have, such as high blood pressure, sleep apnea, or high cholesterol 
  • Managing stress in a healthy way
  • Connecting with people who face similar challenges in a diabetes prevention program or support group

Medication for prediabetes  

Medication isn’t usually recommended for people with prediabetes. Your HCP may suggest taking medication to reduce your blood sugar levels if your risk of type 2 diabetes is especially high. Medications typically prescribed include metformin and acarbose. You might also be prescribed medication to control related issues like high blood pressure or high cholesterol.

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What are the possible complications of prediabetes?

Prediabetes is associated with several possible health complications, the most common of which include:

Type 2 diabetes

Not surprisingly, type 2 diabetes is the primary complication of prediabetes. It occurs when your body can’t use insulin properly and blood sugar reaches dangerous levels. Type 2 diabetes is the most common form of diabetes, making up between 90 and 95 percent of all cases.

Type 1 diabetes—a less common form of diabetes—occurs when your body can’t produce insulin. It’s in part a disorder of the immune system that may be caused by genetics or environmental factors, such as viruses.

Treatment for type 2 diabetes usually focuses on managing the disease, although some cases may be reversible. The most common treatment options include regular exercise, a healthy diet, and medication to help control blood sugar levels. Insulin therapy may also be recommended if lifestyle changes and medication aren’t enough to manage diabetes.  

Type 2 diabetes that is left untreated or poorly managed may lead to kidney failure, heart disease, stroke, and blindness. It may also contribute to nerve damage and vascular disease (disease of the blood vessels) that can result in loss of a leg, foot, or toes due to medically necessary amputation.  

Heart disease and stroke

Prediabetes can contribute to heart disease and stroke. Heart disease refers to several conditions that damage blood vessels, cause blood clots, or affect the heart’s structure and function. A stroke occurs when a blood vessel that supplies oxygen to the brain becomes blocked or ruptures. Elevated blood sugar levels cause inflammation that can narrow blood vessels and affect how blood flows to and from the heart and brain.

A 2021 study published in the Journal of the American College of Cardiology found that people with prediabetes have a significantly higher chance of experiencing a heart attack, stroke, or other major cardiovascular (heart-related) event than people with normal blood sugar levels. The link between prediabetes and heart disease was strongest among Black people, overweight individuals, and people with a family history of cardiovascular disease.

Treatment for heart disease will vary according to its type and severity. In general, many types of heart disease are addressed through a combination of lifestyle changes, medicine, and surgery.  A stroke requires immediate medical attention in a hospital setting, followed by rehabilitation to help restore movement, speech, or other impaired functions.

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Can you prevent prediabetes?

Smiling mature man running in a park to promote good health and prevent prediabetes

Preventing prediabetes looks similar to treating prediabetes. Adopting these healthy lifestyle habits can help keep your blood sugar levels in a healthy range and lower your risk of both prediabetes and diabetes:

  • Get regular exercise (shoot for around 150 minutes of moderate-intensity aerobic activity per week)
  • Avoid or quit smoking  
  • Eat healthy foods (like vegetables, lean proteins, and complex carbohydrates) and cut back on added sugar in your diet
  • Maintain a healthy body weight
  • Keep blood pressure and cholesterol levels in check  

Even with these measures, it’s still possible to develop prediabetes if you have a strong family history of diabetes. Ask your HCP about ways you can address your individual prediabetes risk factors and maintain good health.

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What is the outlook for prediabetes?

Someone with prediabetes has about a 70 percent chance of developing type 2 diabetes in their lifetime. The risk of developing diabetes within one year is roughly 10 percent.

Being diagnosed with prediabetes is an opportunity to stop diabetes before it starts. With action, most cases of prediabetes are reversible. Living a healthy lifestyle and following your HCP’s guidance can help you improve your blood sugar levels, avoid complications like heart disease and stroke, and prevent prediabetes from advancing to diabetes.

Your HCP will likely check your blood sugar levels at least once a year if you have prediabetes. This is also the case for children and adolescents with the condition.  

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Living with prediabetes

A prediabetes diagnosis can feel alarming and overwhelming. But remember: It is possible to change your health.

Revamping your diet and exercising regularly can be challenging. Try to take things one day at a time and celebrate small victories. That might mean choosing to exercise after a stressful day instead of reaching for a sugary snack. Habit tweaks like these can keep you moving toward your goal.

In addition to your HCP’s guidance, these tips can help you live well with prediabetes:

  • Prioritize your mental health: This may involve sharing your concerns with loved ones, joining a support group, or speaking with a licensed mental health provider. Dealing with health challenges can be scary. Just remember that you don’t have to go it alone.
  • Join a community: Exercising with friends or family, attending group fitness classes, or teaming up with someone else managing the condition can help you stay on track as you work toward your health goals. Joining a lifestyle change program is also beneficial for many people with diabetes.
  • Educate yourself and your loved ones: Learning more about prediabetes and how blood sugar affects your body can help you make educated and confident decisions. Sharing information with loved ones can also help them support you through challenges.
  • Give yourself grace: The path to reversing prediabetes isn’t always straight or easy. You’ll inevitably face ups and downs as you work to change your habits. What you’re doing isn’t easy, so show yourself some compassion. At the end of the day, progress is more important than perfection.  

To discover more about prediabetes, its treatment options, and how you can prevent diabetes, speak with your HCP. You can also check out resources from trusted organizations like the American Diabetes Association and the Centers for Disease Control and Prevention.

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Featured prediabetes articles

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American Academy of Family Physicians. Prediabetes. Familydoctor.org. Last updated May 31, 2023.   

American College of Cardiology. Prediabetes May Not Be as Benign as Once Thought. Published May 5, 2021.

American Diabetes Association. Diagnosis. Accessed January 16, 2023.    

American Diabetes Association Professional Practice Committee; 2. Diagnosis and classification of diabetes: Standards of care in diabetes—2024. Diabetes Care 1 January 2024; 47 (Supplement_1): S20–S42.

American Heart Association. Carbohydrates. Last reviewed September 12, 2023.

Centers for Disease Control and Prevention. About Prediabetes and Type 2 Diabetes. Last reviewed August 1, 2023.   

Centers for Disease Control and Prevention. Are You Up to Date on Your Preventive Care? Last reviewed April 19, 2023.  

Centers for Disease Control and Prevention. How Much Physical Activity Do Adults Need? Last reviewed June 2, 2022.

Centers for Disease Control and Prevention. Making Physical Activity a Part of a Child’s Life. Last reviewed June 28, 2023.

Centers for Disease Control and Prevention. National Diabetes Statistics Report. Last reviewed November 29, 2023.

Centers for Disease Control and Prevention. Prediabetes – Your Chance to Prevent Type 2 Diabetes. Last reviewed December 30, 2022.  

Cleveland Clinic. Prediabetes. Last reviewed November 8, 2023.  

Endocrine Society. Children With Prediabetes and Obesity May Be More Likely to Progress to Diabetes. Published October 12, 2023.   

Harvard Health Publishing. Pre-Diabetes. Published February 22, 2022.

Liu J, Li Y, Zhang D, Yi SS, Liu J. Trends in prediabetes among youths in the US from 1999 through 2018. JAMA Pediatr. 2022;176(6):608-611. 

Mayo Clinic. Glucose Tolerance Test. Last reviewed March 24, 2022.

Mayo Clinic. Prediabetes. Last reviewed November 11, 2023.

MedlinePlus. Prediabetes. Last updated May 5, 2021. 

Michel, A, Mando, R, Waheed, M. et al. Prediabetes associated with an increase in major adverse cardiovascular events. J Am Coll Cardiol. 2021 May, 77 (18_Supplement_2) 14.

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