What is diabetes mellitus (DM)?

• A. A group of metabolic diseases characterized by hyperglycemia due to defects in insulin secretion, insulin action, or both.
• B. A group of liver disorders causing low blood sugar.
• C. A rare genetic disorder of bone metabolism.
• D. A disease affecting only children with no insulin production.

Answer: (A)

Diabetes mellitus is a group of metabolic diseases defined by chronic hyperglycemia due to defects in insulin secretion, insulin action, or both. Insulin helps glucose move from the blood into cells; when insulin is absent or not working well, glucose stays in the blood, leading to high blood sugar and over time to various complications.

This category includes type 1 diabetes, where the body's immune system destroys pancreatic beta cells producing little or no insulin; type 2 diabetes, characterized by insulin resistance with a relative deficiency; and gestational diabetes, which occurs during pregnancy. It can affect people of any age, not just children.

The other descriptions reference conditions that are not diabetes: liver disorders causing hypoglycemia, a bone metabolism disease, or a disease limited to children with no insulin production.