The Epidemiology of Adult Obstructive Sleep Apnea
Highlights of the 2008 publication by the ATS Journal Online
Despite the numerous advancements in our understanding of the pathogenesis and clinical consequences of OSA, a majority of those affected remain undiagnosed.
Snoring and Obstructive Sleep Apnea is characterized by recurrent episodes of partial or complete collapse of the upper airway during sleep.
The prevalence of obstructive sleep apnea associated with accompanying daytime sleepiness is approximately 3 - 7% for adult men and 2 - 5% for adult women. Disease prevalence is higher in different population subsets, including overweight or obese people, those of a minority race, and older individuals.
Weight change is an important determinant of disease progression and regression. Those that have a 10% increase in their weight had on average a 32% increase in their AHI and a six fold risk of developing moderate to severe obstructive sleep apnea.
The overall incidence of moderate-to-severe obstructive sleep apnea (AHI ≥ 15 events/h) over a 5-year period was 11.1% and 4.9% in men and women, respectively.
The consistency of the effects of body weight on disease progression of many patients with obstructive sleep apnea present a history of recent weight gain.
It is remarkable that despite all of the clinical and scientific advancements regarding obstructive sleep apnea. A great majority (70–80%) of those affected remain undiagnosed. The lack of an appropriate level of case identification is partially driven by the fact that patients are frequently unaware of the associated symptoms that are often identified either by a bed partner or family member. Compounding the lack of patient awareness, health care professionals in most medical specialties have not received the necessary training to help expedite case finding and institute early intervention.
Here are the risk factors for obstructive sleep apnea:
There is a high prevalence of obstructive sleep apnea with advancing age. More than 50% of adults over the age of 65 years have some form of chronic sleep-related complaints. 70% of men and 56% of women between 65 and 99 years of age have obstructive sleep apnea defined as an AHI of at least 10 events per hour. Disease prevalence increases steadily with age and reaches a plateau after the age of 60 years.
Excess body weight is a common clinical finding and is present in more than 60% of the patients referred for a diagnostic sleep evaluation. Epidemiologic studies from around the world have consistently identified body weight as the strongest risk factor for obstructive sleep apnea. One standard deviation difference in body mass index (BMI) was associated with a 4-fold increase in disease prevalence.
It has long been recognized that men have greater vulnerability than women toward developing obstructive sleep apnea. Clinic-based studies have shown that, in patients referred for clinical evaluation, the ratio of men to women is in the range from 5 to 8:1.
Minority populations often have a higher prevalence of comorbid medical conditions, including obesity. These factors, in conjunction with a low socioeconomic status and disadvantages in health care, could explain the higher prevalence of obstructive sleep apnea.
Several soft and hard tissue factors can alter the mechanical properties of the upper airway and increase its propensity to collapse during sleep.
Familial and Genetic Predisposition
Several large-scale studies have confirmed a role for inheritance and familial factors in the genesis of obstructive sleep apnea. First-degree relatives of those with the disorder are more likely to be at risk compared with first-degree relatives of those without the disorder.
Smoking and Alcohol Use
Cigarette smoking and alcohol have been suggested as possible risk factors for obstructive sleep apnea. Epidemiologic investigations show that current smoking is associated with a higher prevalence of snoring and obstructive sleep apnea.
The ingestion of alcohol before sleep has been shown to increase upper airway collapsibility or the precipitate of obstructive apneas and hypopneas during sleep.
Besides the unfavorable effects on daytime sleep tendency and cognitive performance, obstructive sleep apnea also has been implicated in the etiology of cardiovascular conditions, including hypertension, coronary artery disease, congestive heart failure, diabetes and stroke.
There is now a wealth of information indicating that untreated obstructive sleep apnea is associated with an increased risk of fatal and nonfatal cardiovascular event, a higher propensity of sudden death during sleep, and a greater risk for stroke and all-cause mortality. As data supporting a causal role of obstructive sleep apnea in medical complications continues to increase, a concerted effort by health care professional across specialties is needed to recognize those that remain undiagnosed. By posing a few additional questions during the routine clinical interview, patients in need for further diagnostic testing can be easily identified especially if there are co-existing medical conditions. Finally, it is imperative that medical education at all levels incorporate instruction on the risks of obstructive sleep apnea and other sleep disorders. Given the high prevalence and public health burden of obstructive sleep apnea, the implications of untreated disease for the individual and society are enormous and cannot be ignored.
Sleep Apnea Facts and Figures by ResMed a developer, manufacturer and distributer of medical equipment for treating, diagnosing, and managing sleep-disordered breathing.
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