Prediabetes is extremely common. Over 115 million American adults are currently living with the condition, and globally, more than 1 billion adults between ages 20 and 79 have blood sugar levels above normal but below the diabetes threshold. Perhaps most striking: 8 in 10 adults with prediabetes don’t know they have it.
U.S. and Global Prevalence
In the United States, prediabetes affects roughly one in three adults. That 115 million figure from the American Diabetes Association makes it one of the most widespread metabolic conditions in the country, yet it remains largely invisible because it rarely causes noticeable symptoms.
The picture is similar worldwide. The International Diabetes Federation estimates that 635 million adults have impaired glucose tolerance (blood sugar that spikes too high after eating) and another 488 million have elevated fasting blood sugar. Combined, that’s over 1 billion people in a gray zone between normal blood sugar and full diabetes. These numbers have risen steadily over the past two decades, driven by increases in obesity, sedentary lifestyles, and aging populations.
Prediabetes in Adolescents
This isn’t only an adult problem. CDC surveillance data from 2023 found that an estimated 8.4 million U.S. adolescents aged 12 to 17 had prediabetes. That’s roughly 32.7% of the adolescent population. The same diagnostic thresholds used for adults apply here: fasting blood sugar between 100 and 125 mg/dL, or an A1C between 5.7% and 6.4%. Rising rates of childhood obesity are a major driver, and the trend suggests the overall burden of type 2 diabetes will continue growing as these young people age.
Why So Many People Don’t Know
The 80% unawareness rate is the defining feature of prediabetes as a public health problem. Blood sugar in the prediabetic range doesn’t typically make you feel sick. There’s no pain, no obvious fatigue pattern, no visible change. Most people find out only when a routine blood test flags elevated numbers, which means anyone who skips regular checkups can carry the condition for years without a clue.
Three simple blood tests can identify it. An A1C test measures your average blood sugar over the past two to three months; a result between 5.7% and 6.4% indicates prediabetes. A fasting blood sugar test taken after an overnight fast falls in the prediabetes range at 100 to 125 mg/dL. An oral glucose tolerance test, which measures blood sugar two hours after drinking a sugary solution, signals prediabetes at 140 to 199 mg/dL. Any one of these results is enough for a diagnosis.
Who Is Most at Risk
Age is one of the strongest predictors. Prediabetes prevalence climbs significantly after age 45, and adults over 65 have the highest rates. But the adolescent data show clearly that age alone doesn’t tell the whole story.
Other major risk factors include carrying excess weight (especially around the midsection), having a parent or sibling with type 2 diabetes, being physically inactive, and having a history of gestational diabetes. Certain racial and ethnic groups, including Black, Hispanic, Asian American, and Native American populations, face higher risk, partly due to genetic predisposition and partly due to disparities in access to healthy food and healthcare.
What Happens if Prediabetes Goes Unchecked
Each year, an estimated 5 to 10% of people with prediabetes progress to type 2 diabetes. That may sound modest as an annual figure, but compounded over five or ten years, it means a large share of people with prediabetes will eventually cross the diabetes threshold if nothing changes.
The risks aren’t limited to diabetes. Research published in Harvard Health found that people with prediabetes face a meaningfully higher risk of cardiovascular problems, including coronary artery disease, stroke, and heart failure, compared to people with normal blood sugar. Over a median follow-up of nearly 12 years, the elevated risk was consistent, suggesting that even “borderline” blood sugar takes a toll on blood vessels and the heart over time. Prediabetes isn’t a harmless waiting room before diabetes. It’s a condition with its own health consequences.
How Effectively It Can Be Reversed
The good news is that prediabetes responds well to lifestyle changes, and the evidence behind that claim is unusually strong. The landmark Diabetes Prevention Program study, which the CDC’s National DPP is modeled on, showed that participants who lost 5 to 7% of their body weight (about 10 to 14 pounds for someone weighing 200 pounds) and added regular moderate exercise cut their risk of developing type 2 diabetes by 58%. In practical terms, that means a structured program of healthier eating and about 150 minutes of physical activity per week can cut your diabetes risk roughly in half.
Those results held across age groups and racial backgrounds. For adults over 60 in the original study, the risk reduction was even higher. The lifestyle changes don’t need to be dramatic. Walking counts. Incremental dietary shifts, like reducing sugary drinks and processed carbohydrates, make a measurable difference. The key is consistency over months rather than intensity over days.
The CDC-recognized National DPP is available through health systems, community organizations, and online platforms across the country. Many insurance plans cover it, including Medicare for qualifying adults. Programs typically run for a year, with weekly group sessions in the first six months focused on building sustainable habits around food, activity, and stress management.