## **Core Concept**
Obstructive sleep apnea (OSA) is a sleep disorder characterized by repeated episodes of upper airway obstruction during sleep, leading to reduced airflow (hypopnea) or complete airflow cessation (apnea). This condition is often associated with obesity, male gender, and specific anatomical and physiological factors.

## **Why the Correct Answer is Right**
The correct answer, ., implies that we are looking for a statement that is **not true** about obstructive sleep apnea. Typically, OSA is associated with:

- Obesity: Increases the risk due to fat deposition around the airway.
- Male gender: Men are more likely to develop OSA than women, especially in the pre-menopausal age group.
- Age: Risk increases with age.
- Specific symptoms: Loud snoring, witnessed apneas, and daytime sleepiness.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Typically, obesity is a risk factor for OSA, so if option A states that obesity is not a risk factor, it would be incorrect.
- **Option B:** If option B correctly identifies a characteristic or risk factor of OSA (e.g., male gender, obesity), then it would be incorrect as the "not true" statement.
- **Option C:** Similar to option B, if it accurately describes OSA, it would not be the correct answer to this question.
- **Option D:** If option D also accurately describes a feature or consequence of OSA, then it too would be an incorrect statement regarding what is "not true" about OSA.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that **obstructive sleep apnea can lead to significant cardiovascular morbidity**, including hypertension, heart failure, and increased risk of stroke. The intermittent hypoxia and sleep fragmentation seen in OSA contribute to these complications.

## **Correct Answer: D.**