March 2010

Identifying Patients at Risk for Sleep Apnea

David Claman, M.D.
Critical Care Specialist and Pulmonologist
Director, UCSF Sleep Disorders Center

Sleep apnea, which is as common as adult diabetes, can significantly increase a person's risk for hypertension, stroke and heart attack. But the condition often goes undiagnosed, partly due to a lack of awareness, even though the condition can be easily diagnosed.

Patients who suffer from sleep apnea stop breathing repeatedly during sleep, sometimes hundreds of times each night and often for longer than a minute. With each apnea event, the brain briefly arouses the sleeping person to resume breathing and interrupts sleep.

Obstructive sleep apnea (OSA), the most common form of the disease, occurs when the muscles in the wall of the throat relax and collapse during sleep, obstructing airflow. Central sleep apnea occurs less frequently and is believed to be related to irregularities in the brain's normal signal to breathe, leading to interrupted sleep.

Risk Factors

Risk factors for sleep apnea include:

  • Age — People over the age of 40 are more likely to suffer from sleep apnea, although people of all ages, including children, can be affected
  • Gender — Men are more likely to suffer from sleep apnea, although women also are affected
  • Snoring — One of the most common markers
  • Weight — Being overweight is the main risk factor

Identifying Sleep Apnea

Obesity — a BMI of over 30 — is the most common risk factor in adults. Thin people, however, can develop the condition if anatomic issues are present such as enlarged tonsils. Several other factors can be used to identify patients suffering from sleep apnea.

When trying to identify sleep apnea, questions to ask patients include:

  • Do you snore?
  • Has anyone seen you stop breathing while you are sleeping?
  • Do you get sleepy during the day?
  • Do you experience sleepiness while driving?
  • Do you suffer from difficult to control hypertension?

Diagnosing Sleep Apnea

Sleep apnea is most accurately diagnosed with a polysomnography, an overnight sleep study during which a patient's sleep cycles and stages are measured by recording brain waves (EEG), electrical activity of muscles, eye movement, breathing rate, blood pressure, blood oxygen saturation and heart rhythm.

A specially trained technician observes the patient while he or she sleeps.


Lifestyle Modifications

Some patients may benefit from lifestyle changes and behavior modification, most notably weight loss. A 10 percent weight loss has been shown to reduce sleep apnea by 25 percent.

Other modifications include:

  • Sleeping on one's side, rather than on the back
  • Avoid drinking alcohol three hours prior to bedtime

Continuous Positive Airway Pressure (CPAP)

Continuous positive airway pressure (CPAP), a machine that delivers air through a facial mask worn while sleeping, is the most effective treatment for sleep apnea. Research has shown that regular and continuous use of CPAP significantly reduces daytime sleepiness and reduces cardiovascular morbidity in patients with severe apnea.

Some patients find wearing a facial mask uncomfortable or don't respond to CPAP. These patients should be referred to an oral and maxillofacial surgeon or otolaryngologist to discuss dental devices and surgical treatment options.


Surgery may be performed by an otolaryngologist or maxillofacial surgeon to improve the flow of air through the nose and throat. These surgeries involve cutting or manipulating the upper airway, including the throat, tongue, jaw and nose.

Surgery has been shown effective in 40 to 50 percent of carefully selected patients. Patients with enlarged tonsils have a higher rate of surgical success.

UCSF Sleep Disorders Center

One of the few of its kind in Northern California, the UCSF Sleep Disorders Center evaluates and treats a full range of sleep disorders. The center is fully accredited by the American Academy of Sleep Medicine.

It offers polysomnography and support groups for people with sleep disorders. The center's team works closely with other UCSF specialists, such as otolaryngologists and oral and maxillofacial surgeons, to develop and coordinate a treatment plan for patients.


Researchers at UCSF recently discovered the first gene involved in regulating the optimal length of human sleep, offering a window into a key aspect of slumber.

The team, reporting in the Aug. 14, 2009 issue of Science, identified a mutated gene that allows two members of an extended family to thrive on six hours of sleep a day rather than the eight to eight-and-a-half hours that studies have shown humans need over time to maintain optimal health. Working from this discovery, scientists genetically engineered mice and fruit flies to express the mutated gene and study its impact.

The finding offers an opportunity to unravel the regulatory mechanism of sleep. While the mutation may be rare, it could offer a probe more generally into the regulatory mechanisms of sleep quality and quantity. Understanding these mechanisms could lead to interventions to alleviate pathologies associated with sleep disorders.

Other Resources

For more information, contact the Physician Referral Service at UCSF Medical Center:

Phone (888) 689-UCSF or (888) 689-8273