What Causes Sleep Apnea

What causes sleep apnea?

Any factor can cause the narrowing of the airway, and the upper airway obstruction may cause nocturnal hypoxia during sleep, leading to sleep apnea syndrome. The main common causes are:

• Aging:

The prevalence of OSA (obstructive sleep apnea) increases with age from young adulthood through the age of 60s and 70s, then appears to plateau.

• Gender:

The OSA is two to three times more common in men than in women. But between men and the peri- and post-menopausal women, the gender difference in prevalence is not as great.

• Obesity:

For both men and women, the prevalence of OSA increases with increasing BMI and some weight-related indicators such as neck circumference, waist-to-hip ratio. Studies have found that a 10% weight gain can increase the risk of developing OSA by 6 times.

• Upper airway structure abnormalities:

The obstruction of the upper airway (oral cavity, nasal cavity, and pharynx) caused by various reasons, including nasal diseases/nasal congestion such as deviated or crooked nasal septum, turbinate hypertrophy, sinus polyps, etc., oral and pharyngeal factors such as tonsil and adenoid hypertrophy, an overly long or floppy soft palate, elongated uvula, swollen tongue, the back of the tongue base, etc., craniofacial abnormalities such as the smaller-than-normal lower jaw, and upper airway narrowing caused by other reasons such as infection, trauma or surgery, etc.

• Drinking alcohol or using sedative-hypnotic drugs:

These substances can make the soft tissues of the upper airway more flaccid, which will obstruct the airflow, make breathing more difficult, cause sleep apnea, and prolong the duration of apnea.

• Smoking:

Smoking may increase the risk of developing OSA, or at least worsen existing symptoms. In one study, current smokers were three times more likely to have OSA than those who had smoked in the past (but had quit) or who had never smoked.

• Other diseases causing sleep apnea syndrome:

cerebrovascular disease, congestive heart failure, hypothyroidism, acromegaly, vocal fold paralysis, brain tumors, neuromuscular disorders, laryngopharyngeal reflux, gastroesophageal reflux, and airway compression due to mediastinal mass. These diseases mentioned above can cause or aggravate airway resistance, thus causing sleep apnea.

Other medical conditions that may have an increased association with OSA include obesity hypoventilation syndrome, hypertension (particularly resistant hypertension), cardiovascular disease, atrial fibrillation, pulmonary hypertension, end-stage kidney disease, chronic lung disease, including asthma, chronic obstructive pulmonary disease (COPD), and idiopathic, pulmonary fibrosis; stroke and transient ischemic attacks, pregnancy ( gestational diabetes, pregnancy-induced hypertension), acromegaly, hypothyroidism, polycystic ovary syndrome, Parkinson’s disease, floppy eyelid syndrome.

Who is most affected by sleep apnea?

• Sleep apnea syndrome is most common in people who are obese, especially those who are centripetally obese with thicker necks and larger hips.
• Men are more likely to develop OSA than women.
• People who are older are also more likely to have OSA.
• In terms of facial appearance, people with small mouths and small lower jaws are more likely to develop OSA.
• People who smoke or drink alcohol for a long time or take sedative drugs before bedtime are also at high risk for OSA.
• In addition, there is a certain degree of familial aggregation of OSA, which may be related to genetic factors and common lifestyle habits. For example, genetic factors may make most of the family have small mouths and jaws, or common lifestyle habits make more overweight people in the family, etc.
• Furthermore, the development of OSA is associated with the onset of certain specific medical conditions, such as women who are pregnant are more likely to develop OSA than women who are not pregnant; and menopausal women are at greater risk of developing OSA compared to premenopausal women.

What are the conditions that predispose to sleep apnea syndrome?

Sleeping in the supine position, drinking alcohol, or using sedative-hypnotic drugs before bedtime can significantly increase the risk of apnea during sleep that night, and worsen existing OSA symptoms.