What is type 1 diabetes?

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    Last Updated: May 16, 2025

    Type 1 diabetes is a disease characterized by high blood glucose levels due to the immune system attacking and destroying insulin-producing pancreatic beta cells. It typically begins in childhood or adolescence and tends to be more prevalent in regions farther from the equator, particularly in Northern European countries.

    Diabetes is a disease in which blood glucose levels are too high. In type 1 diabetes (T1D), the immune system attacks and destroys pancreatic beta cells that make insulin — a hormone that tells cells to absorb and use glucose for energy.[1] T1D usually begins during childhood or adolescence, but it can occur at any age. The prevalence of T1D tends to increase as you travel away from the equator, with rates substantially greater in Finland and other Northern European nations than in China and Venezuela.[2]