Abstract
Purpose of Review: The purpose of this review is to summarize the evidence for the association between obesity and obstructive sleep apnea (OSA), as well as predisposing risk factors and treatment strategies for OSA amongst obese patients.
Recent Findings: Recent findings highlight a number of factors including sex, age, upper airway structure and ethnicity, which may predispose patients to OSA when obese. Both invasive and noninvasive weight-reduction strategies also show positive signs of being an effective means to reduce or remediate OSA amongst obese adults and children.
Summary: In view of recent findings, a direct association between body mass and upper airway obstruction should be viewed with caution. Obesity may play a more significant role in the predisposition to OSA amongst particular subgroups of the population, such as adults, and those with particular craniofacial and upper airway morphology. Healthcare prioritization and requirements may be more substantial for such groups. Further, commonly used treatment methods for OSA (such as adenotonsillectomy for children and continuous positive airway pressure for adults) may be less effective for obese individuals. Weight-reduction strategies appear important for an optimal outcome, and such strategies may be more or less invasive depending on the severity of obesity, OSA or both, and other patient complications.
Introduction
The prevalence of overweight and obesity in the community continues to grow at an alarming rate despite a growing awareness of the significant morbidity associated with this condition. Amongst such morbidity, obesity is considered a major risk factor for upper airway obstruction during sleep, with increased body mass being associated with three to four-fold increase in severity of upper airway obstruction amongst adults. These associations are particularly notable amongst male adults who display comparatively more central fat deposition. By contrast to adults, the contribution of body mass to severity of upper airway obstruction during sleep in children is less clear and is likely to be dependent on a number of mediating factors including age, ethnicity and adenotonsillar hypertrophy.
In the USA, the prevalence of obesity is reported to have increased from around 22% in adults between 1988 and 1994 to over 30% in 2003-2004. The prevalence of obesity amongst children has risen from around 10% between 1988 and 1991 to around 17% in 2003-2004. Similar trends have been observed in a number of other nations. Clinically significant sleep-related upper airway obstruction, or obstructive sleep apnea (OSA), is reported in 4% of male adults and 2% of female adults, with OSA present in 40% of obese adults and over 90% of morbidly obese adults. Amongst children, the prevalence of OSA is estimated at 1-4%, whereas 20-30% of obese children demonstrate OSA. It is not known whether the incidence of OSA is also increasing in line with rates of obesity. Nonetheless, the marked morbidity associated with both obesity and OSA, and the reported associations between conditions, are of increasing concern in the context of increased obesity amongst the community. A greater understanding of the nature of these associations will lead to better treatment and management plans. The purpose of this review is not to discuss in detail all that is currently known about these conditions or the association between them and related mechanisms. Rather, it is to discuss in general the reported risk for OSA that obesity presents across all ages and to draw particular attention to major advances in knowledge that have been reported over the last 1-2 years.
This brief review of recent advances in knowledge of the risk for development of OSA amongst obese patients has identified two primary areas of interest, namely, a greater understanding of risk factors, which predispose obese individuals to develop OSA, and treatment effects amongst obese individuals with OSA. Both these topics are discussed for adults and children separately.