Burden of sleep apnea: rationale, design, and major findings of the Wisconsin Sleep Cohort study

Abstract

Context: Untreated sleep apnea is a prevalent but treatable condition of breathing pauses during sleep. With approximately 15% of the US population affected, understanding of the total health burden is necessary to guide policy, population initiatives, and clinical practice to reduce the prevalence of this condition.

Objective: To outline the history and need for a population approach to understanding sleep apnea and provide a review of the first longitudinal population study of this disorder.

Data source: The results of cross-sectional and longitudinal data from 1500 participants in the Wisconsin Sleep Cohort, initiated 2 decades ago, illustrate the population burden of sleep apnea.

Results: The prevalence of sleep apnea is increasing with trends of increased obesity. Prospective findings from 4- to 15-year follow-up data indicate untreated sleep apnea predicts increased blood pressure, hypertension, stroke, depression, and mortality.

Conclusions: The high prevalence of untreated sleep apnea and links to serious morbidity and mortality underscore the population burden of this condition and the need for greater clinical recognition and strategies to reduce prevalence.

Figures

Figure 1

The basic design and study protocol of the Wisconsin Sleep Cohort, which included the following: 18 channel poly-somnography; health history, medication, lifestyle, demographics interview; depression, anxiety scales; Epworth Sleepiness Scale; sleep problems (insomnia, RLS, sleepiness, etc) inventory; blood pressure: standard seated, arm: ankle index, 24-hour ambulatory monitoring; body habitus measures: weight, height, circumferences, skin fold; neuropsychological test battery; fasting blood sample; cardiovascular function, eg, carotid IMT; objective sleepiness (MSLT); Performance, reaction time (PVT); Horne-Ostberg, sleep diaries, DMV accident reports, death records, quality of life (SF36); genetic analyses, 24-hour ambulatory blood pressure. Abbreviations: RLS, Restless Leg Syndrome; IMT, Intima Media Thickness; MSLT, Multiple Sleep Latency Test; PVT, Psychomotor Vigilance Task; DMV, Department of Motor Vehicles.