Causes of Sleep Apnea

History and Causes of Sleep Apnea

There are many risk factors to look for when evaluating for OSA. Not all have to be present for a problem to exist. Your records should include notes on the presence of the following risk factors and symptoms.

Question: What can cause Obstructive Sleep Apnea?

Answer: Anything that narrows or causes a blockage in the upper airway.

Obesity (Weight Gain)

Persons who are clinically obese (BMI >30) are more likely to suffer from OSA. A BMI calculation should be performed as part of a basic health history screening on all patients. Fatty cells deposited in the throat can put outside pressure on the airway causing it to narrow and collapse. Obese patients are also more likely to have a large tongue which also contributes to the problem of a narrowed airway.

People who otherwise have never noted a problem who gain a relatively small amount of weight, 5-15lbs, frequently report snoring more frequently. This indicates the airway was compromised and could ultimately lead to OSA. A regular snorer who gains a small amount of weight could become someone with OSA.

Large Neck Circumference

A neck circumference greater than 17” and 15” for men and women respectively indicates an increased likelihood of OSA.

NOTE: The large neck circumference noted above does not need to be due to fatty tissue or obesity for it to be a problem. Several studies done on NFL players have noted a dramatic increase in OSA prevalence. The large neck size on the men studied was largely due to muscle mass and not fat deposits.


As we age, we typically gain weight and lose muscle tone. The combination of the two leads to increased instances of OSA in older populations. In a community sample of people over 65, one study noted OSA was present in 65% of the population.


According to studies the ratio of OSA from men to women is 2.5-1. Interestingly, the ratio of men to women who undergo a full night study at a sleep lab is 8-1. This is thought to be due to the fact that many women underreport their symptoms (especially snoring) which leads to under referral to sleep centers.

Several studies have indicated that the prevalence of OSA in women seems to increase after menopause. In these studies women taking hormone replacement therapy did not show the noted increase in OSA. This increase in OSA is thought to be caused by women’s bodies depositing and storing fat differently after hormone production slows down.

Anatomic Abnormalities / Facial Deformities

An enlarged tongue, constricted maxillary arch, high palate, retrognathic mandible, deviated septum and a variety of other conditions relating to tongue and mandibular position as well as narrow facial bone structure can have and adverse effect on the airway.


While snoring itself can also be a side effect of OSA, it is also a risk factor. Just about all OSA sufferer’s are snorers, but not all snorers have OSA. Snoring alone, while not harmless, is more of a social problem than a clinical one. However, the act of snoring can batter the uvula and tissues of the soft palate and throat. This can cause those tissues to become inflamed which ads to the restriction of the airway and could cause OSA.

Alcohol / Sedative Use

Alcohol consumption (especially before bedtime) and sedative use (even sleeping pills) can contribute to OSA. They relax muscle tone in the upper airway which can lead to airway collapse and OSA.

Smoking, while not a sedative, can also increase risk for OSA. Smoking irritates and inflames the tissues of the upper-airway. Even a slight amount of inflammation can narrow the airway enough to cause a problem.

Enlarged Tonsils & Adenoids

The most common cause of OSA in children is enlarged tonsils. Referral to a competent Ear Nose & Throat specialist who is aware of the relationship between enlarged tonsils and OSA is critical. A tonsil evaluation should be part of a records/history appointment with every patient. See the protocol section for specific tonsil grades.

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