Diabetes is a chronic metabolic disorder in which blood sugar stays too high — either because the pancreas isn’t producing enough insulin, because the body has stopped responding to the insulin it does produce, or both. Insulin is the hormone that lets glucose move from the bloodstream into cells to be used for energy. When that system fails, glucose builds up in the blood and quietly damages the heart, kidneys, eyes, and nerves — often for years before most people feel anything.

It is one of the fastest-growing chronic diseases on the planet. The International Diabetes Federation’s 2025 Diabetes Atlas estimates that 589 million adults — roughly 1 in 9 people worldwide — are now living with diabetes, and that number is projected to reach 853 million by 2050. More than 4 in 10 of the people who already have it don’t yet know.