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Association between measures of and prognostic significance of cardiorespiratory fitness in community-dwelling older adults

Yazdanyar, Ali (2011) Association between measures of and prognostic significance of cardiorespiratory fitness in community-dwelling older adults. Doctoral Dissertation, University of Pittsburgh.

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    Abstract

    The age structure of the U.S. population is expected to change with the segment of the population aged over 65 years experiencing the largest increase in size. Given the expected change in the U.S. population, efforts aimed at screening and diagnosis, in addition to the prevention and treatment of diseases with a significant burden in older adults should be at the forefront of public health efforts. Accordingly, in order to obtain an appreciation of the significance of cardiovascular diseases in older adults we initially performed a literature review of the burden and prevention of cardiovascular diseases, the leading cause of morbidity and mortality in older adults. Subsequently, we focused our research efforts on cardiorespiratory fitness in older adults. Cardiorespiratory fitness is a determinant of morbidity and mortality in middle-aged and older adults which can be measured objectively by either exercise testing or walk-based tests. Few studies of community-dwelling older adults have characterized the relationship between fitness as assessed by exercise testing versus walk-based testing, with subclinical cardiovascular, or the prognostic significance of walk-based test performance. We sought to characterize these relationships among community-dwelling adults participating in the Cardiovascular Health Study (CHS). In an analysis of the Arterial Calcification in the Elderly (ACE-CHS), 6 Minute Walk test (6 MWT) performance was a useful measure of treadmill test capability and performance. A second analysis of ACE-CHS failed to identify subclinical cardiovascular disease as quantified by the coronary artery calcification score as a significant determinant of exercise duration in exercise treadmill testing. However, the coronary artery calcification score was associated with ischemia as detected by electrocardiographic changes during exercise testing. Finally, in the full CHS cohort, the 6 MWT performance was independently associated with all-cause mortality, demonstrating a prognostic value for submaximal fitness assessment using the 6 MWT across a wide range of function present in community-dwelling older adults. The public health relevance of these finding is the potential clinical utility of the 6 MWT, a quick, safe and inexpensive alternative to exercise treadmill testing, in the assessment of cardiorespiratory fitness and the prediction of mortality in community-dwelling older adults.


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    Item Type: University of Pittsburgh ETD
    ETD Committee:
    ETD Committee TypeCommittee MemberEmailORCID
    Committee ChairNewman, Anne Bnewmana@edc.pitt.edu
    Committee MemberEdmundowicz, DanielEdmuD@upmc.edu
    Committee MemberSutton-Tyrrell, Kimtyrrell@edc.pitt.edu
    Committee MemberKuller, Lewiskullerl@edc.pitt.edu
    Committee MemberBoudreau, Robertboudreaur@edc.pitt.edu
    Title: Association between measures of and prognostic significance of cardiorespiratory fitness in community-dwelling older adults
    Status: Unpublished
    Abstract: The age structure of the U.S. population is expected to change with the segment of the population aged over 65 years experiencing the largest increase in size. Given the expected change in the U.S. population, efforts aimed at screening and diagnosis, in addition to the prevention and treatment of diseases with a significant burden in older adults should be at the forefront of public health efforts. Accordingly, in order to obtain an appreciation of the significance of cardiovascular diseases in older adults we initially performed a literature review of the burden and prevention of cardiovascular diseases, the leading cause of morbidity and mortality in older adults. Subsequently, we focused our research efforts on cardiorespiratory fitness in older adults. Cardiorespiratory fitness is a determinant of morbidity and mortality in middle-aged and older adults which can be measured objectively by either exercise testing or walk-based tests. Few studies of community-dwelling older adults have characterized the relationship between fitness as assessed by exercise testing versus walk-based testing, with subclinical cardiovascular, or the prognostic significance of walk-based test performance. We sought to characterize these relationships among community-dwelling adults participating in the Cardiovascular Health Study (CHS). In an analysis of the Arterial Calcification in the Elderly (ACE-CHS), 6 Minute Walk test (6 MWT) performance was a useful measure of treadmill test capability and performance. A second analysis of ACE-CHS failed to identify subclinical cardiovascular disease as quantified by the coronary artery calcification score as a significant determinant of exercise duration in exercise treadmill testing. However, the coronary artery calcification score was associated with ischemia as detected by electrocardiographic changes during exercise testing. Finally, in the full CHS cohort, the 6 MWT performance was independently associated with all-cause mortality, demonstrating a prognostic value for submaximal fitness assessment using the 6 MWT across a wide range of function present in community-dwelling older adults. The public health relevance of these finding is the potential clinical utility of the 6 MWT, a quick, safe and inexpensive alternative to exercise treadmill testing, in the assessment of cardiorespiratory fitness and the prediction of mortality in community-dwelling older adults.
    Date: 29 June 2011
    Date Type: Completion
    Defense Date: 28 March 2011
    Approval Date: 29 June 2011
    Submission Date: 04 April 2011
    Access Restriction: 5 year -- Restrict access to University of Pittsburgh for a period of 5 years.
    Patent pending: No
    Institution: University of Pittsburgh
    Thesis Type: Doctoral Dissertation
    Refereed: Yes
    Degree: PhD - Doctor of Philosophy
    URN: etd-04042011-171221
    Uncontrolled Keywords: cardiovascular disease; mortality; six minute walk test
    Schools and Programs: Graduate School of Public Health > Epidemiology
    Date Deposited: 10 Nov 2011 14:34
    Last Modified: 13 Apr 2012 14:25
    Other ID: http://etd.library.pitt.edu/ETD/available/etd-04042011-171221/, etd-04042011-171221

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