About 589 million adults worldwide are living with diabetes, which works out to roughly one in every nine people. That number has grown dramatically over recent decades, and projections suggest it will keep climbing. In the United States alone, 40.1 million people have diabetes, or about one in eight Americans.
Global Numbers at a Glance
As of 2024, diabetes affects 11.1% of the global adult population. The International Diabetes Federation’s latest estimates, published in The Lancet Diabetes & Endocrinology, put the total at 589 million adults. Perhaps more striking is the gap between those numbers and how many people actually know they have the disease: an estimated 252 million people with diabetes worldwide have not yet been diagnosed. That means more than four in ten people living with the condition are completely unaware of it.
More than 95% of all diabetes cases are type 2, the form closely linked to weight, physical inactivity, and metabolic health. Type 1 diabetes, where the immune system destroys the cells that produce insulin, accounts for the remaining small percentage but requires lifelong insulin treatment from the point of diagnosis.
Diabetes in the United States
The CDC reports that 40.1 million Americans have diabetes. That one-in-eight ratio is slightly higher than the global average, reflecting both the country’s rates of obesity and its relatively robust diagnostic infrastructure. Even so, more than one in four U.S. adults with diabetes don’t know they have it. That translates to roughly 10 million Americans walking around with elevated blood sugar that’s silently damaging blood vessels, nerves, kidneys, and eyes.
Beyond those already diagnosed or undiagnosed, the pipeline of people heading toward diabetes is enormous. An estimated 115.2 million American adults have prediabetes, a condition where blood sugar is elevated but not yet high enough for a diabetes diagnosis. That’s more than two in five adults. Eight in ten of them don’t know it. Prediabetes is reversible with lifestyle changes like increased physical activity and modest weight loss, which makes the lack of awareness especially costly.
Rising Rates in Children and Teens
Diabetes is no longer a condition that mainly affects middle-aged and older adults. Among young people in the United States, new type 1 diabetes diagnoses rose from 20 per 100,000 in 2002 to 22 per 100,000 by 2018, a roughly 2% annual increase. Type 2 diabetes in young people climbed even faster: from 9 per 100,000 to 18 per 100,000 over the same period, doubling in just 16 years. That works out to about a 5% increase per year in new type 2 cases among children and adolescents.
The type 2 trend in young people is especially concerning because the disease tends to progress more aggressively when it develops early. A teenager diagnosed with type 2 diabetes faces decades of potential complications, including kidney disease, vision loss, and cardiovascular problems, at ages when those outcomes were historically rare.
Why the Numbers Keep Growing
Several forces are pushing diabetes rates upward simultaneously. Rising obesity rates are the most direct driver of type 2 diabetes. Globally, more people live in urban environments with easy access to processed food and limited opportunities for physical activity. Aging populations also contribute, since the risk of type 2 diabetes increases with age.
Improved screening and diagnostic access play a role too, though in a complicated way. Better detection means more people show up in the statistics, which inflates the apparent prevalence. But with 252 million people still undiagnosed worldwide, current numbers almost certainly undercount the true burden. As healthcare systems expand screening, the reported totals will continue to rise even if new cases somehow leveled off.
The Undiagnosed Problem
The sheer scale of undiagnosed diabetes is one of the most important numbers in this picture. Diabetes causes damage long before symptoms become obvious. High blood sugar gradually injures small blood vessels throughout the body, which is why the disease is a leading cause of blindness, kidney failure, and non-traumatic limb amputations. People who don’t know they have diabetes can’t manage it, and by the time symptoms like blurred vision, frequent urination, or slow-healing wounds prompt a visit to a doctor, years of damage may have already accumulated.
The combination of 589 million people with diabetes globally, 252 million of them undiagnosed, and hundreds of millions more with prediabetes makes this one of the largest chronic health challenges in the world. In the U.S. specifically, adding the 40.1 million with diabetes to the 115.2 million with prediabetes means that nearly half of all American adults have some degree of blood sugar dysregulation.