sleep apnea riskMost people who are at risk of sleep apnea don’t know it. That’s a big problem considering sleep apnea can be life threatening. It can worsen your own health. It can also endanger others. It is responsible for many car accidents and disasters. Do you known your sleep apnea risk?

Sleep apnea risk

Sleep apnea risk depends on symptoms, your anatomy and physical attributes as well as your medical history. Sleep apnea can worsen over time and lead to the development of diabetes, high blood pressure or heart disease and even result in heart attacks or stroke. Most people don’t know that the presence of many medical conditions makes their sleep apnea risk higher. A long list of medical conditions affect the chances that you have obstructive sleep apnea (OSA). If you have or have or have had high blood pressure, diabetes, heart disease, or stroke then your sleep apnea risk is significantly increased. Symptoms like snoring, sleepiness are also common symptoms of OSA. Less commonly known is that waking up at night to urinate, overactive bladder syndrome and depression are also highly associated with sleep apnea. Looking at neck size or inside someones mouth can also show some signs that can identify the chances that you have sleep apnea.

Do you have high blood pressure?

High blood pressure is a major sleep apnea risk factor. If you answered yes, your sleep apnea risk is about 50%. If it’s not controlled with medication then the chances of having sleep apnea may be as high as 80%.

Do you have diabetes?

Diabetes is another major sleep apnea risk factor. If you have diabetes then the risk of sleep apnea is about 70%. This is based on several studies where OSA was present in 58% to 86% of diabetics. If you have pre-diabetes your chances are lower. But 70% of patients with pre-diabetes eventually end up with diabetes.

Do you have heart disease?

Having congestive heart failure, A-fib, atrial fibrillation or coronary artery disease (CAD) all increase your sleep apnea risk factors.
Congestive Heart Failure (CHF)

At least 50% of individuals with heart failure have sleep apnea. There are two common forms of sleep apnea. One is called obstructive sleep apnea and the other is known as central sleep apnea. People with heart failure are at risk of both.

A-fib (Atrial fibrillation)

About 75% of patients with atrial fibrillation have sleep apnea. Individuals with a-fib are at risk for both obstructive sleep apnea and central sleep apnea. Similarly, CPAP likely improves reduces the recurrence of Afib that has been treated.

Coronary artery disease (CAD)

About one in three (30%)of patients who have coronary artery disease have OSA. Coronary artery disease is diagnosed by angiogram where blockages or narrowing of the arteries of the heart are identified. Patients who have coronary artery disease are sometimes treated with stents to open up narrowed vessels or bypass surgery. They may also be treated with agents to treat high blood pressure, diabetes or high cholesterol which may lead to narrowing of blood vessels.


Research demonstrates a correlation between asthma and OSA. Studies on OSA patients show that nearly 35% have evidence of Asthma. Conversely, a study comparing individuals with asthma to others found over the course of 4 years that the risk of sleep apnea was 27%. The study found a relative sleep apnea risk of 1.39 or an increased risk of nearly 40% for patients who have asthma of developing OSA.

History of stroke, mini stroke or TIA

Stroke is a major sleep apnea risk factor. In individuals who have had a “mini stroke”, transient ischemic attack (TIA) or stroke the chances of having OSA are between 50% and 70%. Treating sleep apnea can prevent additional strokes or cardiovascular complications. Individuals with residual symptoms (loss of sensation, weakness etc.) from the stroke appear to be at higher risk. Therefore, a sleep study is essential in individuals with a history of any of these.


Being overweight is a sleep apnea risk factor. With a body mass index (BMI) of greater than 30 your chances of having OSA are between 20 and 40%. If your BMI is above 40, your chances are about 40%. If your BMI is around 50, then chances are 1 in 2 you will have sleep apnea. So if you are a little on the heavy side getting tested for sleep apnea may be a good idea. You may be at risk of sleep apnea. What is your BMI? You can calculate it here.

Acid reflux or GERD?

It has been shown that about 60% of individuals who have OSA also have acid reflux. For these individuals, treatment with CPAP appears to help. Other studies have not shown a clear relationship between the risk of sleep apnea and GERD (gastroesophageal reflux disease). The risk for developing OSA if you have GERD is not established.

Waking up to urinate?

Frequent episodes of waking at night to urinate (nocturia) is associated with snoring and the risk of sleep apnea. It has been reported that the association increases from 52% of individuals with primary snoring, to 57.2%, 64.3% and 76.9% of patients who have mild, moderate and severe OSA. A small study of 21 women, including 16 with Overactive bladder (OAB) showed that nearly 80% had evidence of OSA. Given the high prevalence in the general population of nocturia (10% over age 20, around 60% in 50s and around 80% in 80s), by itself, nocturia is not a sleep apnea risk factor or a good predictor for developing OSA. Still, sleep apnea should be considered for patients who wake up frequently to urinate or who have OAB. In addition the treatment of sleep apnea has been shown to relieve the urge to urinate at night in some people.


It is believed that sleep apnea may cause depression and vice versa. One large study on nearly 19,000 individuals surveyed by phone found that 18% with a diagnosis of OSA (or another SDB) were depressed. In this cohort, depression was 5 times more likely in the individuals who had OSA compared to those who did not have OSA. Several smaller studies either support or conflict this data. Data showing that patients who have received treatment for sleep apnea also have improvement in their depression further supports the sleep apnea risk in individuals who have depression.

Thyroid disease

Patients with hypothyroidism have a mildly increased risk of sleep apnea. This relationship may also be related to factors such as obesity or male gender that are associated with thyroid disease then making sleep apnea more likely. Similarly, up to 10% of patients with OSA have hypothyroidism. Treatment of hypothyroidism may help reverse the risk of sleep apnea that is found in these cases. Current recommendations, however, do not support screening for hypothyroidism in all sleep apnea patients.

Other disorders

Sleep apnea risk in polycystic ovary syndrome (PCOS)

Individuals with PCOS have cystic ovaries, increased androgens leading to hirsutism, acne, insulin resistance, and fertility issues. They have a 20% to 50% chance of also having OSA.

Risk of sleep apnea in nonalcoholic fatty liver disease (NAFLD aka NASH)

People with NAFLD have a 50% risk of sleep apnea.


It is true if you have sleep apnea, you probably snore (70-95% of patients with apnea snore). But not everyone who routinely snores has a risk of sleep apnea. Primary snoring (or snoring without sleep apnea) occurs in about half of men and about 1 in 4 women. That being said, if any other symptom or physical finding of sleep apnea is present or if an associated medical condition is present the risk of sleep apnea increases dramatically. It has also been shown that louder snoring is more predictive of OSA than quieter snoring. For example, snoring that can be heard by a bed partner is less of a sleep apnea risk factor than snoring that can be heard in another room outside of the bedroom. It is a good idea though for all individuals with snoring to be evaluated for other risks or physical findings of sleep apnea to determine if further diagnostic testing is warranted.


Excessive sleepiness is one of the most common symptoms of sleep apnea. Sleepiness may be caused by many things other than sleep apnea, including sleep deprivation caused by insufficient sleep, medical conditions, or as a side effect from medication. Research shows that over 85% of patients with sleep apnea are excessively sleepy. When combined with other symptoms like snoring, there is an increased risk of sleep apnea. Therefore, a sleep study may be indicated, especially with sufficient sleep of greater than 7 hours a night. Evaluation by a trained physician may be a good place to start, since excessive sleepiness is epidemic in our society. How can one tell if they are excessively sleepy? One way is to take a validated survey such as the Epworth Sleepiness Scale. A score of 10 or more indicates that you are too sleepy.

Crowded airway (hint: look in your mouth)

risk of sleep apneaIndividuals who have airway crowding have a higher chance of having sleep apnea. The Modified Mallampati also known as the Friedman score, was created by anesthesiologists to measure airway crowding. It assigns a score of 1 to 4, with 4 being the most crowded. The picture to the right is the original Mallampati. To accurately do the modified Mallampati one should open their mouth, without saying “ah” or sticking out their tongue. Most studies have shown individuals with a score of 3 to 4 are about two and a half times more likely to have apnea.

Neck circumference (hint: use a tape measure)

If you are a male with a neck circumference of greater than 17 inches or a female with a size 16 inch neck or greater, you have an increased risk of sleep apnea and should probably have a sleep study. How would you know? Collar size or measuring tape. Collar size is usually provided in inches or centimeters. However, many individuals wear a collar size that is a half inch larger than their neck circumference. For your reference, 40 cm is about 16 inches (15.7 to be exact), 43 cm is about 17 inches. As neck size increases, so does risk. At a neck size of 19 inches or 48 cm, the chances of having OSA are about 20 times higher. As rare as a size that large might seem, one study showed that over 90% of individuals with a neck size of greater than 16 inches will have sleep apnea. In the same study having a neck size of less than 16 inches did not mean you would not have sleep apnea. Neck circumference correlates highly with airway narrowing and collapsiblility.


21. Nuckton TJ, Glidden DV, Browner WS, Claman DM. Physical examination: Mallampati score as an independent predictor of obstructive sleep apnea. Sleep. 2006;29:903–8.
22. Kushida CA, Efron B, Guilleminault C. A predictive morphometric model for the obstructive sleep apnea syndrome. Ann Intern Med. 1997;127:581-587.
23. Principles and practice of sleep medicine. 5th ed. St. Louis:Elsevier/Saunders; 2010.

Michael Morgenstern, MD
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Michael Morgenstern, MD

About the author: Dr. Michael Morgenstern is double board certified in Neurology and Sleep Medicine and the founder of the American Sleep Apnea Society. He is the Director of the Morgenstern Medical in Lake Success, NY, where he treats patients with sleep disorders and other neurological conditions.
Michael Morgenstern, MD
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