Purpose: The primary objectives were to 1) examine the dose-response relationship between physical activity and mortality in individuals with CAD, and 2) determine whether the aforementioned relationship is consistent within strata of other personal characteristics.
Methods: Subjects included 1045 elderly men and women with CAD from the Cardiovascular Health Study. In the first set of analyses, the dose-response relationship between baseline leisure-time physical activity level and all-cause mortality risk over 9 yr was determined using Cox proportional hazards regression models. Next, the subjects were stratified based on several different characteristics, and the consistency of the relationship between baseline leisure-time physical activity and mortality risk within the various strata was determined.
Results: Baseline leisure-time physical activity was related to all-cause mortality risk in a curvilinear dose-response manner such that greater differences in mortality risk were seen at the lower end of the energy expenditure scale, with a plateau occurring at approximately 4000 kcal·wk−1. Within various strata of sex, age, smoking, adiposity, self-perceived health status, number of comorbid conditions, and type of CAD; the relative risks of mortality were lower in active participants (≥1500 kcal·wk−1) in comparison with inactive participants (<1500 kcal·wk−1).
Conclusion: This study highlights the inverse graded relationship between physical activity and all-cause mortality in men and women with CAD. Physical inactivity was a risk factor for mortality regardless of whether the subjects were men or women, old or very old, smokers or nonsmokers, lean or overweight, or otherwise healthy or unhealthy.
1School of Physical and Health Education and 2Department of Community Health and Epidemiology, Queen's University, Kingston, Ontario, CANADA
Address for correspondence: Ian Janssen, Ph.D., School of Physical and Health Education, Queen's University, Kingston, Ontario, Canada K7L 3N6; E-mail: email@example.com.
Submitted for publication August 2005.
Accepted for publication October 2005.