Clinical reviewGender differences in obstructive sleep apnea and treatment implications
Introduction
Disordered breathing during sleep is a common abnormality resulting in excessive daytime somnolence and numerous physiologic illnesses for millions of Americans. Sleep apnea is defined as a repetitive, intermittent cessation of airflow at the nose and mouth while sleeping, and the clinical syndrome is marked by recurrent episodes of apneas (complete cessation of breathing) and hypopneas (partial decrease in breathing) during sleep. These episodes can be due to two causes which include occlusion of the upper respiratory tract (URT) airway (obstructive) or absence of breathing effort (central).1 Obstructive sleep apnea (OSA) is an independent risk factor for hypertension and other cardiovascular disease such as stroke and myocardial infarction.2, 3, 4, *5, *6 It has also been reported to play a role in the pathogenesis of insulin resistance and type II diabetes.7 In addition to these effects, the excessive daytime sleepiness associated with OSA has been implicated in motor vehicle accidents and a general decrease in quality of life.8, 9 OSA represents a major public health issue.
One intriguing aspect of OSA is the difference in the prevalence of the disease between genders. Research study has repeatedly and consistently confirmed that OSA is more common in men than women.*10, *11 Although this complex topic is still poorly understood, it is believed that inherent differences in fat distribution, length and collapsibility of the upper airway, neurochemical control mechanisms, arousal response, and sex hormones all contribute to the disparity in prevalence between the genders.12
Section snippets
Clinical presentation
Sleep-disordered breathing (SDB) occurs in 24% of young-middle aged men and 9% of women13 and in 70% of older men and 56% of older women.14 The male-to-female ratio is estimated between 3:1 and 5:1 in the general population and at 8:1 to 10:1 in some clinical populations.*10, *11 It has been postulated that the higher clinical ratio may be a result of the fact that women do not show the “classic” symptomotology and thus may be under-diagnosed. Women presenting with daytime sleepiness may be
Sleep architecture and arousal
Men and women with OSA have notable differences in sleep architecture.27 A study by Valencia-Flores et al. noted that in OSA patients, women had longer sleep latencies, greater amounts of slow wave sleep, and fewer awakenings during the night than men despite no significant differences in age, respiratory disturbance index, or oxygen saturation.28 O’Connor et al. showed that women tended to have milder OSA which occurred predominately during rapid eye movement (REM) sleep, in contrast to men
Treatment implications
It is clear that numerous mechanisms are at play when it comes to the disease pathogenesis of OSA. Despite the widely disparate variables that contribute to disease pathogenesis, treatment options for the disease are surprisingly limited. Currently, the cornerstone of treatment of OSA is continuous positive airway pressure (CPAP). Essentially, application of CPAP acts as a “pneumatic splint” of the upper airway and also works to dilate upper airway musculature.119 Oral appliances, devices which
Summary
OSA is more common in men than women. Presenting symptoms are often different—with women complaining of insomnia and depression. Thus, it is possible that women are under-diagnosed, which in itself poses a large public health problem and places many women at risk for cardiovascular and neurocognitive sequelae as well as decreased quality of life. Differences in upper airway anatomy, neurochemical mechanisms, the response to arousal, fat distribution, and sex hormones all contribute to the
Acknowledgments
This research was supported by NIA AG08415 and a grant from the Farrell Fund of the San Diego Foundation.
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