Diabetes Mellitus Overview, Definition, Causes, Statistics in 2025 and 2026: A Review

Abstract

Diabetes is a group of chronic illnesses that affect how the body uses glucose, or blood sugar, as its primary energy source. The disease is caused by either inadequate insulin synthesis or ineffective insulin use. The hormone insulin, which is secreted by the pancreas, helps cells absorb glucose. Although the causes vary depending on the type, the basic idea of diabetes is a problem with the body's synthesis or use of insulin.

Damage is often associated with persistently elevated blood sugar and its impact on blood vessels and neurons. Extremely high blood sugar and the short-term effects of diabetes. The most recent global statistics for 2025 and 2026 show that diabetes is still one of the chronic illnesses with the fastest rate of rise worldwide. Global figures for 2025 are provided by the Diabetes Atlas 2025 edition and the International Diabetes Federation (IDF). Diabetes affects 589 million people worldwide who are between the ages of 20 and 79. This is equivalent to one in nine people on the planet. There are about 252 million people with diabetes who have not been diagnosed. Nearly 3.4 million deaths in 2024 were attributed to diabetes, according to the most recent data published in 2025.