With increase in life expectancy, there has also been a parallel increase in chronic co- morbidities that impair functional status and quality of life in older age. Converging lines of evidence link sleep quality and quantity with cardiovascular health. A considerable body of literature demonstrates that short sleep duration (<7 hours) is associated with increased levels of cardiovascular disease (CVD) risk factors including obesity, hypertension, and diabetes in population-based studies. Further, evidence suggests that poor health status also increases the prevalence of sleep disorders. This relationship may be particularly prominent in older adults, who often have the burden of both sleep disturbances and medical co-morbidities. The proposed study is uniquely able to examine these matters cross-sectionally (in older people), and prospectively -- in particular the relation of early adult CVD risk factor levels to sleep quality and sleep disorders in older age by examining a pre-assembled cohort of the Chicago Heart Association Study with CVD risk status characterized approximately 40 years ago.
The specific aims are to: a) determine the relationship between CVD risk status, especially low risk (LR), at ages 25-44 with subsequent sleep quality, levels of daytime sleepiness, and sleep apnea in older age (65-79);b) assess whether change in risk factor status from ages 25-44 to older age relates to sleep quality, daytime sleepiness, sleep apnea, neuropsychological performance, and cardiovascular health status in older age, and c) explore relationships among current CVD risk factors, CVD, sleep quality, sleepiness, sleep apnea, daytime neuropsychological performance, and other variables in older age. Both objective and subjective measures of sleep are to be used in conjunction with measures of CVD risk (BMI, blood pressure, lipids, glucose, smoking, C-reactive protein), clinical and subclinical CVD (coronary artery calcium, ankle brachial index), obtained by the recently funded parent grant (R01 HL081141;Principal Investigator, Martha L. Daviglus). 1,380 participants, identified at baseline as LR for CVD or not LR for CVD, are to undergo subjective and objective sleep measures (questionnaires and actigraphy). A subset of 150 participants (50 LR who do not become high risk by older age, 50 LR who became high risk, and 50 high risk at baseline who remain so in older age) are to attend the laboratory for more detailed physiological studies of sleep. By leveraging resources of the parent grant, this ancillary study is uniquely positioned to study these multiple relationships among CVD risk at ages 25-44, sleep variables, and other traits in older age. Results of this study can have important implications theoretical and practical, e.g., for prevention and treatment of sleep disorders and CVD in later life.
Recent studies indicate a strong link between sleep and sleep disorders, such as sleep apnea with cardiovascular health. A considerable body of evidence clearly demonstrates that short sleep duration disrupts metabolic and cardiovascular function and has been associated with increased levels of cardiovascular risk factors, such as C-reactive protein, BMI, blood pressure, lipids, coronary artery calcium, ankle brachial index, glucose, and smoking. Therefore, an improved understanding of the relationship between sleep and cardiovascular health will lead to preventive approaches and treatment strategies to improve function, health, and overall quality of life in the growing population of older adults.
