Which of the following is NOT one of the three Ds of niacin deficiency?

Niacin deficiency, a condition that can lead to pellegra, is characterized by a classic triad of symptoms known as the three Ds: dermatitis, diarrhea, and dementia. Each of these symptoms is directly associated with insufficient niacin (vitamin B3) levels in the body.

Dermatitis typically presents as a rash that occurs in sun-exposed areas of the body, which can be quite severe and distinctive. Diarrhea is another hallmark, leading to gastrointestinal disruptions and potential malnutrition. Dementia, or cognitive decline, is the third component of this triad, representing mental effects resulting from chronic niacin deficiency.

Diabetes, while it has associations with various nutritional deficiencies and metabolic issues, is not part of the classic presentation of niacin deficiency. Therefore, the inclusion of diabetes in this context is inaccurate when identifying symptoms associated with niacin deficiency. The clear distinction of niacin's classic three Ds—dermatitis, diarrhea, and dementia—makes it evident that diabetes does not belong in this category.