**Question:** Which one of the following statements about non insulin dependent diabetes mellitus (NIDDM) is NOT true -

A. NIDDM is also known as type 2 diabetes mellitus.
B. Insulin resistance is the primary defect in NIDDM.
C. Beta cell dysfunction also contributes to the pathogenesis of NIDDM.
D. NIDDM is primarily seen in young adults.

**Correct Answer:** D. NIDDM is primarily seen in young adults.

**Core Concept:**
Non insulin dependent diabetes mellitus (NIDDM), also known as type 2 diabetes mellitus, is a chronic disorder characterized by hyperglycemia, resulting from defects in insulin action and secretion. The pathogenesis of NIDDM involves insulin resistance and beta cell dysfunction. This type of diabetes is typically seen in older adults, particularly those who are overweight or have a family history of type 2 diabetes.

**Why the Correct Answer is Right:**
NIDDM is primarily seen in older adults, especially those with obesity or a family history of type 2 diabetes. Insulin resistance and beta cell dysfunction are the key pathophysiological defects that lead to hyperglycemia in this condition.

**Why Each Wrong Option is Incorrect:**
A. NIDDM is also known as type 2 diabetes mellitus. This is correct and reinforces the understanding of the condition's classification.
B. Insulin resistance is the primary defect in NIDDM. While insulin resistance is a key feature of the disease, it is not the sole defect. Beta cell dysfunction contributes to the pathogenesis as well.
C. Beta cell dysfunction also contributes to the pathogenesis of NIDDM. This is also correct and highlights the importance of both insulin resistance and beta cell dysfunction in NIDDM.
D. NIDDM is primarily seen in young adults. This statement is incorrect, as NIDDM is predominantly found in older adults, not young adults.

**Clinical Pearl:**
Understanding the typical demographic and pathophysiology of NIDDM is crucial for clinical practice, as it helps in correctly diagnosing and managing patients with this condition. A correct diagnosis enables appropriate treatment strategies and prevents misdiagnosis or unnecessary investigations.