Rationale, design and findings from the Wisconsin Sleep Cohort Study: Toward understanding the total societal burden of sleep disordered breathing.

Over the past 2 decades, clinical and public health recognition of the importance of sleep-disordered breathing (SDB) and other sleep disorders has increased markedly. Findings from epidemiology studies, many of which were presented at the University of Pennsylvania–Hershey symposium (November 2007, ‘‘Epidemiology of Sleep Disorders: Clinical Implications’’) have been critical in identifying the high prevalence of undiagnosed SDB and in linking this disorder with significant morbidity. Identification of the high prevalence of undiagnosed SDB by populationbased studies in the 1990s contributed to the growing increase in clinical recognition of SDB. The increase in clinical interest, in turn, prompted the need for additional epidemiology studies to quantify the adverse health outcomes of this condition, to determine the total societal burden of SDB. Thus, the rationale for the Wisconsin Sleep Cohort Study (WSCS) and other population-based studies, and the significance of findings, must be explained in the context of the fascinating history of sleep medicine.