Epidemiological insights into the public health burden of sleep disordered breathing: sex differences in survival among sleep clinic patients
- Department of Preventive Medicine, University of Wisconsin, Madison, Wisconsin, USA
- Dr T Young.
Recognition that sleep disordered breathing (SDB) is prevalent but largely undiagnosed in adults has prompted the needs to assess the public health burden of this disorder and devise appropriate prevention and intervention strategies.1 2 Before this can be accomplished, both population and clinic-based epidemiology studies are required to understand the natural history, risk factors and adverse health sequelae of this disorder, and to determine what severity levels are of clinical and public health significance. In this report, epidemiological advances and research needs are briefly summarised. In the second part of this paper we focus on the need for epidemiological research into sex differences in the natural history of SDB and present new findings that suggest women with SDB may have poorer survival than men.
Although prevalence estimates of SDB vary according to definitions and methods of measurement, there is general agreement among the most rigorous studies that the prevalence of SDB meeting clinical criteria for sleep apnoea syndrome is in the range of 2–4%.3 In the largest population based study conducted with in-laboratory polysomnography, the prevalence of SDB in middle aged adults in the USA based on lesser severity—for example, an apnoea/hypopnoea index (AHI) of 5 or more—has been estimated at 9% for women and 24% for men.4 Other studies conducted elsewhere in the western world have yielded similar estimates.5 In addition to establishing the high prevalence of SDB, these population-based studies have shown, as is evident in the preceding prevalence estimate, that this is not a disease predominantly of men. Furthermore, women with SDB have been shown to have the same symptoms, risk factors, and health correlates as men.6 The discrepancy between the ratio of men to women with SDB in clinic patient populations (8:1) and in the general population (2–3:1) has underscored the …