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What is an Obstructive Sleep Apnea (OSA)?

In Greek “apnea” translates to “without breath” and is characterized by repetitive episodes of blocked or restricted breaths sometimes hundreds of times during a single night and affects millions of Americans. There are three types of sleep apnea: Obstructive, central, and mixed. Obstructive sleep apnea (OSA) is caused by changes in the position of the tongue during sleep that result in the closure of the soft tissues at the rear of the throat.

Central sleep apnea is caused by the failure of the brain to send breathing control signals to the muscles responsible for breathing. Mixed sleep apnea is a combination of both obstructive and central, and Obstructive Sleep Apnea is the most prevalent of the three. OSA is characterized by the complete obstruction of airway causing breathing to cease completely (Apnea) or partially (Hypopnea) for intervals ranging from seconds to minutes. The human airway (at the level of the thorax) is lined by soft tissue, any collapse of its walls results in the closure of the airway which leads to insufficient oxygen intake, thereby interrupting one’s sleep (episodes or micro-arousals). Obstructive sleep apnea is a potentially life-threatening disease that often goes undiagnosed in most patients affected by sleep apnea^1,2.

The severity of sleep apnea is determined by dividing the number of episodes of apneas and hypopneas lasting ten seconds or more by the number of hours of sleep. The resulting number is called the Apnea-Hypopnea Index, or AHI.^3,4.

AHI #	Condition
Below 5	No OSA
5-15	Mild OSA
15-30	Moderate OSA
Over 30	Severe OSA

Malhotra A, White DP., Obstructive sleep apnoea. Lancet. 2002 Jul 20;360(9328):237-45.
Eckert DJ, Malhotra A, Jordan AS., Mechanisms of apnea. Prog Cardiovasc Dis. 2009 Jan-Feb;51(4):313-23.
http://en.wikipedia.org/wiki/Apnea-hypopnea_index
http://www.healthandage.com/professional/health-center/26/article/2616/gm=20!gid6=6501

How many Americans are affected?

Obstructive Sleep Apnea (OSA) is the most common category of sleep-disordered breathing and affects approximately 38 million Americans (33% of the American adult population; 24% adult men & 9% adult women) with only 20% being diagnosed and treated. Regardless of type, the individual with sleep apnea is rarely aware of having difficulty breathing, even upon awakening, hence OSA remains as one of the most undetected sleep disorders and is often only recognized by others witnessing the individual during episodes. More than 800,000 patients are diagnosed with OSA per year in the USA alone.

http://www.reuters.com/article/pressRelease/idUS167705+15-Apr-2008+BW20080415
Al Lawati NM, Patel SR, Ayas NT., Epidemiology, risk factors, and consequences of obstructive sleep apnea and short sleep duration. Prog Cardiovasc Dis. 2009 Jan-Feb;51(4):285-93.
Obstructive Sleep Apnea, Canaccord Adams: Analysis and Report, 30th May 2007.

Health Effects/Dangers

Short Term Effects:

Sleep Apnea sufferers tend to wake up drowsy in the morning due to interrupted sleep caused by the closure of the airway. The drowsiness results in poorer performance and decreased attention at work, school, and home. Thus problems are more likely to arise between family members and coworkers from the negative social effects of drowsiness. Daytime sleepiness results in seven times more car accidents and deaths¹.

Malhotra A, White DP., Obstructive sleep apnoea. Lancet. 2002 Jul 20;360(9328):237-45.

Long Term Effects:

Obstructive Sleep Apnea has a strong connection with heart disease, stroke, and chronic obstructive pulmonary disease^1,2. 60% of heart disease patients, 70% of stroke patients, and 50% of chronic obstructive pulmonary disease sufferers have OSA. 40% of OSA patients have been shown to have high blood pressure and hypertension^1,2 and OSA patients are three times more likely to suffer from heart disease and four times more likely to have a stroke. The repetitive hypoxia caused by breathing stoppages results in an end-organ system failure and subsequent death^1,2. OSA is known to cause memory problems, increased suicidal ideations or attempts, weight gain, headaches, and impotency and OSA patients are seven times more likely to be involved in an automobile accident^1,2,3. Brain structure (white matter) is extensively affected in OSA patients; axons connecting major structures within the limbic system, pons, frontal, temporal and parietal cortices, and projections to and from the cerebellum, are altered⁴. OSA has been implicated as an independent predictor of mortality that increases the mortality risk by 46% (in middle aged adult men)^5,6.

Qureshi A, Ballard RD., Obstructive sleep apnea. J Allergy Clin Immunol. 2003 Oct;112(4):643-51; quiz 652.
Malhotra A, White DP., Obstructive sleep apnoea. Lancet. 2002 Jul 20;360(9328):237-45.
Goodwin and Marusic., Association Between Short Sleep and Suicidal Ideation and Suicide Attempt Among Adults in the General Population, SLEEP, Vol. 31, No. 8, 2008
Macey et.al., Brain Structural Changes in Obstructive Sleep Apnea, SLEEP, Vol. 31, No. 7, 2008
Marshall et al., Sleep Apnea as an Independent Risk Factor for All-Cause Mortality: The Busselton Health Study, SLEEP, Vol. 31, No. 8, 2008
Naresh M. Punjab et. al., Sleep-Disordered Breathing and Mortality: A Prospective Cohort Study, PLoS Med 6(8): (2009): e1000132. doi:10.1371/journal.pmed.1000132

Potential (Serious) Health Consequences¹
• Hypertension
• Ischemic heart disease
• Cardiac arrhythmias
• Congestive heart failure
• Decreased libido
• Stroke
• LV dysfunction
• Type II Diabetes
• Excessive daytime sleepiness
• Cognitive dysfunction
• Traffic accidents to serious injury due to increased likelihood of traffic accidents

Malhotra A, White DP., Obstructive sleep apnoea. Lancet. 2002 Jul 20;360(9328):237-45.

Symptoms:

OSA Symptoms may be present for years without detection and the patient can become conditioned to them very easily. Some common symptoms include¹

• Excessive snoring
• Daytime drowsiness
• Headaches
• Irritability
• Swelling of legs (in obese patients)
• Tossing and turning during sleep
• Choking/gasping for air while sleeping
• Dry mouth
• Drooling
• Gastro-esophageal reflux
• Diaphoresis
• Sweating and chest pain while sleeping
• Nocturia (the need to get up during the night in order to urinate)
• Irritability/depression
• Loss of energy
• Decreased dexterity
• Personality change
• Memory changes
• Sexual Dysfunction etc.

Qureshi A, Ballard RD., Obstructive sleep apnea. J Allergy Clin Immunol. 2003 Oct;112(4):643-51; quiz 652

Risk Factors:

Gender: Obstructive sleep apnea has been shown to be more prevalent in men than women. 24% of adult men and 9% of adult women in the United States fit the OSA profile^1,5,6.
Ethnicity: African Americans face a higher risk for OSA than any other ethnic group in the United States^5,6.
Obesity^5,6.
Family history: A hereditary connection likely exists but no genetic pattern has been identified⁶.
Alcohol relaxes the throat muscles due to its CNS depression effects triggering or worsening OSA. However, studies are still mixed^2,6.
Body Position: Twice as many sleep apneas occur while one is sleeping on one’s back as opposed to sleeping on one’s side. This may be due to gravity narrowing the throat and allowing the tongue to fall back against the rear of the throat while one is sleeping on one’s back³.
Heavy smokers (two or more packs a day) are 40 times more likely to suffer from OSA than nonsmokers⁶.
Diabetes, Gastro-esophageal Reflux Disease (GERD: common cause of heartburn) and Polycystic Ovarian Syndrome (PCOS) are associated with OSA^4,6
Immune Dysfunction³.

http://www.healthcentral.com/sleep-disorders/sleep-apnea-introduction-000065_4-145.html
http://www.sleepapnea.org/resources/pubs/treatment.html
http://neurology.health-cares.net/sleep-apnea-risk-factors.php
http://health.nytimes.com/health/guides/disease/sleep-apnea/risk-factors.html
Punjabi NM., The epidemiology of adult obstructive sleep apnea. Proc Am Thorac Soc. 2008 Feb 15;5(2):136-43.
Al Lawati NM, Patel SR, Ayas NT., Epidemiology, risk factors, and consequences of obstructive sleep apnea and short sleep duration. Prog Cardiovasc Dis. 2009 Jan-Feb;51(4):285-93.
Obstructive Sleep Apnea, Canaccord Adams: Analysis and Report, 30th May 2007.

Current Treatments

Three of the most popular methods of treating obstructive sleep apnea:

Nasal Continuous Positive Airway Pressure (CPAP): The method consists of pressure-assisted ventilation. CPAP has been shown to lower blood pressure, but CPAP is not always well tolerated by the patient or completely abolish the risk of mortality¹. Side Effects include nasal irritation, stuffiness, eye irritation, and skin abrasion².
1. Kasai T et.al., Prognosis of patients with heart failure and obstructive sleep apnea treated with continuous positive airway pressure, Chest. 2008 Mar;133(3):690-6. Epub 2008 Jan 15.
2. http://www.healthandage.com/professional/health-center/26/article/2616/gm=20!gid2=1760
Oral Appliance Therapy: An appliance is placed within the patient’s mouth with the purpose of keeping the airway open through repositioning of the lower jaw, tongue and the soft palette. An example is the tongue-restraining device¹.
Few reliable data exists in assessing the long-term effectiveness of oral appliance therapy².
1. http://www.ihatecpap.com/oral_appliance.html
2. http://ajrccm.atsjournals.org/cgi/content/full/163/6/1294
Surgical Alternatives: Surgical procedures involving upper airway reconstruction of the soft tissue (uvula and the palate) and bony structure affecting the airway. These include: Uvulopalatopharngeoplasty (UP3), Geniotubercle Advancement with Mandibular Osteostomy, Hyoid Myotomy and Resuspension, Midface Advancement, Tracheostomy, Septoplasty and Turbinate Reduction for nasal obstruction¹. The purpose of the reconstruction is to open the airway to allow greater levels of oxygen intake while sleeping. The effectiveness of these procedures has yet to be determined due to the lack of sufficient clinical data. In addition obesity is a major hindrance of a successful surgery. In some instances, surgery and its side effects may actually worsen the apnea condition of the patient².
1. http://www.sleepdisorderchannel.com/osa/treatment-surgical.shtml#mid
2. http://www.sleepapnea.org/resources/pubs/osa.html

Current Costs

Health care costs prior to OSA diagnosis are at least twice higher than the costs for diagnosed patients who are under treatment¹. Undiagnosed patients use health resources at much higher rates than control subjects particularly for cardiovascular diseases and hypertension. A year delay in the diagnosis of pediatric OSA can result in 226% increase in health care expenses².