Obstructive Sleep Apnoea: Causes And Treatments
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What Is Obstructive Sleep Apnoea?
Obstructive Sleep Apnoea (OSA) (also spelt Obstructive Sleep Apnea) is a sleep disorder where a person’s upper airway either narrows or completely blocks off as the muscles of the throat relax during sleep.
The obstruction results in decreased airflow (hypopneas) or a complete stoppage of airflow (apneas or apnoeas) to the body.
When you stop breathing for a short time, the temporary pauses in airflow require the brain to wake to restore breathing during sleep, resulting in a reduction in deep sleep and lower-quality sleep. The lapses in breathing also lower the body’s oxygen supply, harming the heart and leading to potentially serious health problems.
Although these breathing events can occur hundreds of times a night with severe sleep apnoea, patients often don’t know this is happening.
Sleep Apnoea is both common and can have big health consequences. Thus, it is important for people to be aware of its symptoms, causes, risk factors, diagnosis and treatments.
How Common Is OSA?
Sleep Apnoea is a common sleep disorder and the most common sleep-related breathing disorder.
The percentage of males with the disorder is roughly double the percentage of females.
Postmenopausal women have much higher rates of sleep apnea, about the same as males of a similar age.
Studies show 33.9% of men and 17.4% of women between the ages of 30 and 70 years meet the criteria for at least mild symptoms.
However, sleep apnoea affects people of all ages, from newborns to adults in their nineties.
What Are The Symptoms Of Obstructive Sleep Apnea?
Common symptoms are:
Daytime sleepiness (despite what you might read on other websites, the most common symptom is not snoring, it is daytime sleepiness)
Loud snoring (although snoring is very common and often a good indicator of OSA, it is not specific to this condition).
Gasping or choking while sleeping (this is the single most reliable symptom to indicate sleep apnea (Myers et al. 2013)
Pauses in breathing (witnessed by others)
Insomnia with frequent nighttime awakenings (especially in the hours after 3am)
Waking at night with a racing heart
Restless sleep
Teeth grinding (bruxism)
Frequently needing to pee at night (nocturia)
Waking up feeling unrefreshed
Morning headaches
Waking up with a dry mouth
Cognitive deficits or “brain fog” during the day
Concentration problems
Vivid or threatening dreams
Changes in mood (e.g. depression, irritability)
Memory decline
Erectile dysfunction
Obesity (Body mass index over >25)
Usually a person with sleep apnoea is unaware of their nighttime breathing problems. Often it is a bed partner or family member that makes them aware.
It is important to note that no single sign or symptom can accurately predict a diagnosis.
In general, as OSA gets worse, there are more symptoms and harmful outcomes for the individual.
What Are The Risk Factors For Developing Obstructive Sleep Apnoea?
Risk factors for Obstructive Sleep Apnoea have been well established by scientific studies (Young et al. 2004) and include:
Sex
Age
Ethnicity
Obesity
Upper airway soft tissue abnormalities, and
Craniofacial anatomy.
Other risk factors include:
Smoking
Nasal congestion
Substance use
Medications (benzodiazapines, opiates)
Alcohol
Comorbid or co-occuring medical and mental health conditions
Gastroesophageal reflux (GERD)
Pregnancy
Cardiovascular disease
Polycystic ovarian syndrome (PCOS)
Parkinson’s disease
Chronic lung disease
Hypothyroidism
Obesity hypoventilation syndrome
Type II diabetes
Gender
Being a male is a risk factor for OSA. Men are 2–3x more likely to have OSA than women. 33.9% of men and 17.4% of women between the ages of 30 and 70 years meet the criteria for having at least mild symptoms.
Men have more obstructive sleep apnea due to the dynamics of the upper airway. Men tend to have a large airway but it collapses more easily during jaw movements in sleep.
Men also have a more upper body fat distribution. This means more soft tissue surrounding the neck which increases the risk of OSA.
Postmenopausal women have a 4x increased risk of sleep apnea compared to premenopausal women. Postmenopausal women not on hormone replacement therapy had a 5x greater likelihood of having OSA compared to postmenopausal women on HRT.
Age
Elderly people have 2-3x the prevalence of OSA than middle-aged adults. This is due to increased airway resistance as you age and age-related comorbid conditions (e.g. hypertension which is an OSA risk factor).
Ethnicity
Ethnicity can influence age of onset and severity of OSA. Craniofacial morphology, such as crowded and smaller upper airways, increase the risk of OSA in the Asian population.
Obesity
Obesity is a growing epidemic now affecting over one-third of adults in developed countries such as New Zealand, USA, Great Britain, Australia and Canada.
Obesity is a major risk factor for OSA. Studies have shown that:
BMI > 40 90 % of the patients had an AHI>5 (mild OSA) and 60 % of patients had an AHI>30 (severe OSA)
BMI of 45 94 % of the sample was found to have OSA
10% increased weight = 6x increased risk of obstructive sleep apnoea
Genetics/Family History
Genetic factors like craniofacial structure increase the risk of OSA. Having a first-degree relative with OSA increases the risk of developing obstructive sleep apnea or another sleep-related breathing disorder. Risk increases with more affected family members.
What Are The Causes Of Obstructive Sleep Apnea?
Obstructive sleep apnea happens when the upper airway muscles that keep your breathing passage open while you are awake can no longer keep the airway open and collapse during sleep.
The narrowing, or obstruction, of the airway due to the collapsing, reduces or completely shuts off oxygen flow to the body. For breathing to resume, the brain must wake up and re-open the airway. These awakenings might happen dozens of times each hour and hundreds of time per night. The awakenings disrupt sleep quality, which in turn causes severe daytime sleepiness.
Several factors contribute or cause OSA including
Airway anatomy (e.g. large soft palate);
Airway size;
Pharyngeal collapsibility;
Upper airway dilator muscle activity;
Ventilatory control stability,
Rostral fluid shifts during sleep;
Obesity;
Swollen tonsils:
Health problems like endocrine disorders or heart failure.
What Are Complications Of Obstructive Sleep Apnoea?
Obstructive sleep apnoea is associated with a large and growing number of adverse health outcomes including:
Cardiovascular risk
Metabolic syndrome & insulin resistance
Hypertension
Pulmonary artery hypertension
Coronary artery disease
Cardiac arrhythmias
Heart failure
Stroke
Type 2 Diabetes
Obesity
Gastroesophageal Reflux Disease
Cognitive impairment
Dementia
Preeclampsia
Impotence
Increased overall mortality
Impaired daytime function and quality of life
Increased risk of psychiatric conditions (e.g. depressive and anxiety disorders)
Increased risk of motor vehicle accidents
Cardiovascular Risk
Multiple studies have shown Obstructive sleep apnea (OSA) is associated with increased risk of cardiovascular diseases, even after adjusting common risk factors such as sex, age, body mass index (BMI), and hypertension.
Metabolic Syndrome
Metabolic syndrome is when a person has high blood pressure, diabetes, high cholesterol, and abdominal obesity. Based on the findings of two meta-analyses, those with obstructive sleep apnoea have 2 - 3x increased risk of metabolic syndrome.
Hypertension
A meta-analysis of six studies with 20,637 participants found those with OSA, regardless of severity, were significantly more likely to have systemic hypertension.
Motor Vehicle Deaths
Studies have found that those with OSA have a 2 - 3x risk of vehicle accidents, making OSA a risk for workplace accidents and particularly risky in drivers, pilots, heavy machinery operators, and medics (Strohl et al. 2013).
Increased Overall Mortality
Several meta-analyses have concluded that obstructive sleep apnea increases the risk of death. The increased risk of dying is not only from cardiovascular, but also non-cardiovascular deaths
How Do I Know If I Have Obstructive Sleep Apnoea?
Obstructive sleep apnea can be difficult to identify by the affected individual because they are often asleep while the breathing events are occurring.
For the affected person, the most obvious signs of obstructive sleep apnoea are daytime sleepiness or constantly feeling unrefreshed after waking up (non-restorative sleep). Waking at night with your heart racing, multiple trips to the toilet at night, morning headaches and dry mouth (cotton mouth) may be other signs that are more obvious to the affected individual.
The other key sign that you may have OSA is when a bed partner or family member complains that you snore loudly and/or gasp, choke, or stop breathing while you are asleep.
How Is Obstructive Sleep Apnea Diagnosed?
Obstructive sleep apnoea is diagnosed using an objective sleep assessment (i.e. not a questionnaire or interview) known as an overnight sleep study. There are a growing number of ways that these sleep study tests can be conducted, including from the comfort of your own home.
The American Academy of Sleep Medicine (AASM) clinical guidelines strongly recommend diagnosis of obstructive sleep apnoea is done using either
Polysomnography (PSG); or
A home sleep apnea test; and
A comprehensive sleep evaluation interview
Usually diagnosis is done via a HSAT and a follow up interview with a sleep physician.
Having both the home sleep and interview helps to diagnose OSA and also indicates severity, which determines which treatments will be most useful for the individual.
Screening tools and assessment questionnaires can be used in clinical practice to help to narrow down people with a high likelihood of having OSA. You can take our valid risk of Sleep Apnoea test here.
Polysomnography (PSG)
The gold standard for the diagnosis of OSA is an overnight, in-lab, polysomnographic study in a sleep clinic supervised by a sleep technician. The polysomnogram is considered the gold standard because the PSG provides a large number of channels of information, including activity from the brain, eyes, skin, heart, mouth, nose, chest, and legs, which makes it very accurate.
However, polysomnography is not typically used because a home sleep test is cheaper, easier, and usually adequate to diagnose.
An in-lab overnight study is used when the home test is negative, inconclusive, or technically inadequate. Other times a home test is used is when a person has significant medical problems that make it likely that there may be other sleep-disordered breathing conditions, other non-respiratory sleep disorders, or if there are environmental or personal factors that will make home sleep study tests inaccurate (Kapur et al. 2017).
Home Sleep Apnoea Test (HSAT)
Home sleep apnea testing (HSAT) devices are typically used to diagnose OSA. The most common HSAT device includes a minimum of four recording channels: nasal airflow, respiratory effort, oxygen saturation, and heart rate.
Home sleep apnea tests do not typically monitor sleep itself so lack the sleep stage recordings of the polysomnograph studies.
What Are The Diagnostic Criteria For Obstructive Sleep Apnea?
The diagnosis of OSA is determined by what is called the apnea–hypopnea index (AHI). The AHI is the total number of apneas and hypopneas a person experiences in a night divided by their total sleep time in hours.
An apnea occurs when, for whatever reason, there is a 90 % reduction of airflow in the airway that lasts at least 10sec. An “obstructive apnea” is when the airway is blocked and the person is still trying to breathe but can’t (sometimes there is no effort to breathe and this is termed a “central apnea” and is a different condition known as Central Sleep Apnoea).
A hypopnea occurs when the air passage is partially blocked and there is a reduction of airflow of at least 30% that lasts more than 10sec and results in a 3% decrease in oxygen saturation for the individual.
The different severities of OSA are:
Mild Sleep Apnoea: AHI of 5–15 events per hour of sleep.
Moderate: AHI of 15–30 events per hour of sleep.
Severe: AHI of greater than 30 events per hour.
What Are Obstructive Sleep Apnoea Treatment Options In NZ?
Treatments all have a basic aim of relieving obstructions and keeping the airway open (referred to as “patent”) during sleep. This gets rid of apneas, hypopneas, arousals, oxygen desaturations, and carbon dioxide changes that result in disturbed sleep.
Obstructive sleep apnoea treatments also improve the quality of your sleep and the symptoms you experience during the day.
Treatment options for OSA have grown and keep growing since OSA was first discovered. There are now a range of different options available to those with obstructive sleep apnea.
Positive airway pressure (PAP) therapy is the current gold standard for obstructive sleep apnea treatment and also the most common.
Is Lifestyle Change An Effective Treatment For Obstructive Sleep Apnea?
Studies have shown that both weight loss and exercise can reduce the severity of obstructive sleep apnea. For example, one study found that a 10% weight reduction from typical weight can reduce AHI by 26% (Peppard et al. 2000).
Weight loss can also help improve medical conditions that come with obstructive sleep apnoea and obesity, such as heart problems, hypertension, and lower quality of life.
What Is Oral Appliance Therapy Or Mandibular Advancement Devices For Obstructive Sleep Apnea?
Oral appliances are devices worn in the mouth that help to widen the upper airway and may also reduce the chance that the airway will collapse during sleep.
Mandibular advancement devices (MADs) are the most common oral appliances. A mandibular advancement device holds the lower jaw and or tongue in a forward position during sleep to stop the upper airway from reducing in size.
Oral appliances are a reasonable alternative to PAP therapy for patients with mild to moderate OSA.
What Is Continuous Positive Airway Pressure or CPAP Therapy For Obstructive Sleep Apnoea?
Continuous positive airway pressure (CPAP) is the gold standard “one-size-fits-all” treatment of obstructive sleep apnea.
Continuous positive airway pressure therapy involves wearing a mask over your nose, mouth, or both. A small machine, or CPAP machine forces pressurized air into the airway to stop the airway closing during sleep.
Can Surgery Treat Obstructive Sleep Apnea?
Surgery can be used in the treatment of obstructive sleep apnea if there is an issue with a person’s anatomy that either obstructs the airway or prevents other treatments from being successful.
Surgery is also a second-line therapy if other interventions, such as CPAP, haven’t worked or are intolerable to the patient.
Nasal Surgery
Nasal breathing may be improved with surgeries to correct structural abnormalities such as deviated nasal septum, turbinate hypertrophy, nasal valve collapse, or nasal polyps.
Oropharyngeal and Palatal Surgery
These surgeries aim to widen the airway by reducing airway obstructions and include tonsillectomy, uvulopalatopharyngoplasty (UPPP), tongue reduction, genioglossus advancement, and maxillomandibular advancement.
Maxillomandibular Advancement
Maxillomandibular advancement involves moving the whole lower jaw and attached soft tissues forward to widen the back of the upper airway in your throat.
Upper Airway Stimulation
Also known as hypoglossal nerve stimulation, this treatment involves a surgeon implanting a small device, called a neurostimulator, in the chest. The device electrically stimulates the hypoglossal nerve, which causes tongue movement and prevents airway obstruction during sleep.
Frequently Asked Questions
What Is The Difference Between Snoring And Obstructive Sleep Apnea?
Snoring is the loud noise made when people are breathing in during sleep. Snoring usually indicates that the sleeper has at least a mild obstruction of the upper breathing passage. The sound we call snoring results from vibration in tissues as the person tries to suck air in.
How Do I Know If I Need To Have My Snoring Checked Out?
Most people who snore do not have a medical problem.
If a snorer experiences no daytime sleepiness, has not been observed to stop breathing while asleep, and has normal blood pressure readings, the snoring is unlikely to be a medical problem.
However, if a person has loud snoring for over 10 years there is a high likelihood of at least mild obstructive sleep apnea.
In general, snorers may wish to consider having a medical assessment made, or at least a blood pressure check with their primary care doctor.
Written By: The Better Sleep Clinic
Reviewed By: Dan Ford, Sleep Psychologist
References:
https://doi.org/10.1016/B978-0-323-24288-2.00108-2
https://doi.org/10.2147%2FNSS.S124657