American Journal of Epidemiology Vol. 120, No. 2: 210-224
Copyright © 1984 by The Johns Hopkins University School of Hygiene and Public Health
research-article |
CORONARY RISK FACTORS AND EXERCISE TEST PERFORMANCE IN ASYMPTOMATIC HYPERCHOLESTEROLEMIC MEN: APPLICATION OF PROPORTIONAL HAZARDS ANALYSIS
1Lipid Metabolism-Atherogenesis Branch, National Heart, Lung, and Blood Institute Bethesda, MD 20205
2The Methodist Hospital, Baylor College of Medicine Houston, TX
3Oklahoma Medical Research Foundation Oklahoma City, OK
4Clinical Research Center and Lipid Research Clinic, University of Cincinnati College of Medicine Cincinnati, OH
5Laboratory of Physiological Hygiene, University of Minnesota Minneapolis, MN
6Department of Biostatistics, University of North Carolina Chapel Hill, NC
7Michael's Hospital Toronto, ON, Canada
8Central Electrocardiographic Laboratory, University of Alabama Birmingham, AL
address for reprint requests
The association of established coronary risk factors with submaximal graded treadmill exercise test performance was examined in 6,850 asymptomatic, white 347–59-year-old hypercholesterolemic men screened between 1973 and 1976 at 12 North American Lipid Research Clinics for participation in their Coronary Primary Prevention Trial. The prevalence of ischemic electrocardiographic responses (
mm S-T segment depression) was 8.6%. The Cox proportional hazards method was adapted so as to take into account the level of exercise at which ischemic responses occurred and to which subjects without ischemic responses were exposed. The results were compared with those obtained by standard logistic regression. In both models, age, blood pressure, plasma cholesterol, and (inversely) plasma high-density lipoprotein cholesterol and alcohol consumption were significant independent predictors of an ischemic response to exercise. Surprisingly, ischemic responses were less frequent in smokers than in nonsmokers. However, when the proportional hazards method was used, cigarette smoking was weakly but significantly (p < 0.01) predictive of an ischemic response on the treadmill. Results from this model differed from those of the logistic model because the former takes into account the reduced exercise capacity of smokers, which renders them less likely to reach workloads sufficient to induce myocardial ischemia. The proportional hazards model similarly demonstrated a possible beneficial effect of habitual physical activity which was not apparent in the logistic model. Quetelet index and plasma triglyceride were only weakly associated with the probability of an ischemic response, and did not contribute significantly to either model.
coronary disease; exercise test; hypercholesterolemia; lipids; mathematical models
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  D. S. Siscovick, L. G. Ekelund, J. L. Johnson, Y. Truong, and A. Adler Sensitivity of Exercise Electrocardiography for Acute Cardiac Events During Moderate and Strenuous Physical Activity: The Lipid Research Clinics Coronary Primary Prevention Trial Arch Intern Med, February 1, 1991; 151(2): 325 - 330. [Abstract] [PDF]
|
|