Epidemiology, Risk Factors, and Consequences of Obstructive Sleep Apnea and Short Sleep Duration
Section snippets
Obstructive Sleep Apnea
Obstructive sleep apnea is a common disease characterized by repetitive episodes of airflow cessation (apnea) or airflow reduction (hypopnea) that occur during sleep as a consequence of upper airway collapse. These episodes result in hypoventilation, hypoxemia, recurrent arousals from sleep, and activation of the sympathetic nervous system.
By consensus criteria, an apnea is defined as cessation of airflow for at least 10 seconds using a valid measure of airflow; a hypopnea is present when 1 of
Population Prevalence
Obstructive sleep apnea is a very common disease, whose population prevalence is comparable to that of other important chronic diseases such as asthma, chronic obstructive pulmonary disease, type 2 diabetes, and coronary artery disease.6 In a landmark study, Young et al7 estimated the population prevalence of OSA in middle-aged men and women (30-60 years) in Wisconsin. They estimated that approximately 24% of men and 9% of women have sleep apnea (defined as an AHI ā„5) and that 9% of men and 4%
Prevalence in Other Populations
Obstructive sleep apnea appears even more prevalent in patients with hypertension, with approximately 30% of hypertensive individuals having OSA.12 For instance, in a case-control study by Worsnop et al,13 38% of the 34 untreated and 38% of the 34 treated people with hypertension had apnea-hypopnea indices greater than 5 compared to only 4% of the 25 normotensives. Treated hypertension and untreated hypertension were both associated with the presence of OSA (P = .05 and .06, respectively) after
Obesity
Obesity, especially indicators of central obesity such as neck circumference, is a major risk factor for OSA. Potential mechanisms by which obesity predisposes to OSA are multiple and include: narrowing of the upper airway due to fat deposition, alterations in upper airway function, alterations in balance between ventilatory drive and load, and reduction in lung volumes.22, 23 Prospective studies have shown that a 10% increase in weight was associated with a 6-fold increase in risk for
Family History/Genetics
A number of studies have demonstrated that OSA tends to aggregate within families suggesting the importance of genetics in the development of this disorder.32, 33, 34 The risk of OSA in an individual rises steadily with increasing number of affected relatives.32 The heritability of the AHI has been found to be 30% to 35% in several studies, suggesting one third of the variability in this metric is explained by shared familial factors.35, 36, 37 About 40% of the genetic variance in the AHI is
Other Risk Factors
A number of other patient characteristics have also been identified as risk factors for OSA. These include underlying diseases such as hypothyroidism51 and acromegaly52, 53 (both of which may increase soft tissue size in the upper airway and/or affect respiratory control), use of benzodiazepines54 or other muscle relaxants,55 upper airway structural abnormalities (such as large tonsils), and use of exogenous testosterone.56, 57
Short Sleep Duration
With technological advances and industrialization of society, sleep durations have steadily fallen over the past century. The reduction in sleep times has been further accelerated by the increased prevalence of shift work and the development of 24-hour entertainment with cable television and the Internet. According to a recent survey, 40% of American adults obtain less than the recommended 7 hours of sleep per night.69 Although it has long been apparent that reduced sleep time impairs cognitive
Conclusion
Obstructive sleep apnea is a prevalent condition with moderate to severe disease found in 9% of middle-aged men and 4% of women. The prevalence will likely increase given the current epidemic of obesity. It has a number of potential adverse health consequences, and therapy is effective. It is thus important to consider the diagnosis of OSA in high-risk groups early and initiate treatment promptly if warranted.
Epidemiological research shows that short self-reported sleep duration is associated
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