What primarily defines Type 1 diabetes?

Type 1 diabetes is primarily characterized by a deficiency in insulin release. This condition occurs when the immune system mistakenly attacks and destroys the insulin-producing beta cells in the pancreas. As a result, the body becomes unable to produce sufficient amounts of insulin, which is essential for regulating blood glucose levels. Without adequate insulin, glucose cannot enter the body's cells, leading to elevated levels of glucose in the bloodstream.

In relation to the other options, insulin resistance is more characteristic of Type 2 diabetes, where the body produces insulin but the cells do not respond properly to it. Increased glucose absorption does not directly define any type of diabetes; instead, it relates to how glucose is processed in the body. High blood cholesterol levels may be associated with metabolic syndromes or other health issues, but they are not a defining characteristic of Type 1 diabetes itself.