Though long part of our common wisdom, the fact that inadequate sleep quantity and quality lead to serious health implications have only recently come under scientific scrutiny. Many of the findings have been striking and frightful. Most germane, it is now evident that normal sleep and health are intimately related. People who sleep less or have sleep-disordered breathing (SDB) are at risk for a variety of complications including fasting hyperglycemia and systemic inflammation. SDB is a chronic condition characterized by recurrent collapse of the upper airway during sleep. It is a common disorder in the general population with prevalence estimates that steadily increase with age. In addition, chronic sleep loss has also become a pervasive problem with increasing number of adults of all ages sleeping less at night than ever before. Ultimately, the long-term goal of our proposed research is to understand the mechanisms by which SDB and chronic sleep debt lead to adverse health consequences. For the sake of expediency, frugality, and scientific rigor, we will examine how SDB and short sleep duration are associated with fasting hyperglycemia, insulin resistance, markers of systemic inflammation (i.e., CRP, IL-6, and TNF-1), adipocytokine secretion (leptin) and hypothalamic-pituitary-adrenal (HPA) activity (cortisol). To speed our process of discovery, we will utilize the infrastructure of on ongoing epidemiologic study (The MrOS study) to address the following two specific aims: (1) To assess the cross-sectional and longitudinal associations between indices of SDB severity, glucose metabolism, systemic inflammation, and HPA activity;and (2) To delineate the cross-sectional and longitudinal associations between usual sleep duration, glucose metabolism, systemic inflammation, and HPA activity. The MrOS study is a multi-center cohort study of older men who have been closely followed for seven-year period. Participants have also undergone actigraphy for assessments of usual sleep patterns and polysomnography for the presence and severity of SDB. In addition, DXA- and CT-derived measures of total body and regional fat distribution, respectively, are also available. The current proposal aims to utilize this rich collection of data along with the availability of serum samples which were collected over multiple clinic visits. Together, the proposed studies will address not only whether sleep deprivation and SDB are associated with abnormalities in glucose metabolism and systemic inflammation but will also yield important insight into the basic physiologic mechanisms by which chronic sleep debt and SDB may lead to medical conditions such as hypertension, type 2 diabetes mellitus, and cardiovascular disease.
The overall purpose this research proposal is to determine whether sleep apnea and short sleep duration are related to higher fasting glucose and insulin levels in older community-dwelling men. In addition, we also seek to determine whether men that have sleep apnea and habitually sleep less than other have abnormalities in their cortisol levels and other inflammatory markers that are known risk factors for cardiovascular disease.
