Abstract

Background: It is well known that regular physical activity is associated with lower risk of chronic diseases such as diabetes and cardiovascular disease. Physical activity is also considered an important determinant of metabolic syndrome. All levels of metabolic syndrome, diabetes, and cardiovascular disease are thought to involve inflammation. Physical activity may reduce risk, at least in part, by modifying the inflammatory process. Recent studies have demonstrated an inverse relationship between inflammatory markers, such as high sensitivity C-reactive protein (hs-CRP), and physical activity. Elevated hs-CRP appears to be an independent predictor of both CVD and diabetes. Recent evidence also suggests that hs-CRP is positively associated with all metabolic syndrome characteristics: low high density lipoprotein (HDL), hypertriglyeridemia, hypertension, obesity, and abnormal glucose.

Purpose:The purpose of this study was to examine the relationship between hs- CRP, metabolic syndrome and physical activity. Understanding this relationship will provide insight into the potential of physical activity as a therapeutic option to reduce cardiovascular disease risk.

Methodology: This study relied on a cross-sectional, retrospective analysis of an archival database from the Center for Health Promotion (CHP). Study participants were obtained from a pool of 1,072 men and women patients at the Center of Health Promotion (CHP) at Loma Linda University. Of the 1,072 pool, 173 individuals met the inclusion criteria and were the subjects of the study. Any missing data variables were imputed using the maximum likelihood method (EM) in SYSTAT version 10; SPSS02000. The distribution of hs-CRP, the dependent variable of greatest interest, was positively skewed. Therefore, a log transformation was applied to hs-CRP values for all analyses. Simple regression/correlation analysis was used to evaluate the relationships between log (CRP) and each of the relevant variables: VO2max (ml•kg-1•min-1), metabolic syndrome, and the physical activity status. The following relationships were explored: (1) hs-CRP and metabolic syndrome characteristics, (2) hs-CRP and VO2max, (3) VO2max and metabolic syndrome characteristics, and (4) VO2max and physical activity status. Pearson Chisquare analysis was used to determine if a threshold level of physical activity was associated with hs-CRP changes.

Results: Hs-CRP increased linearly with the number of metabolic syndrome characteristics (p = 0.00022). Inverse associations were found between hs-CRP and VO2max (p = 0.00008) and between VO2max and the number of metabolic syndrome criteria (p = 0.00004). VO2max was positively associated with PA (p = 0.00000). Subjects engaging in 2-3 hours of PA per week had hs-CRP levels < 2.5 mg/L (p = 0.01817).

Conclusions: Physical activity may reduce risk by modifying the inflammatory process. We found that hs-CRP and metabolic syndrome severity were reduced in those with a higher cardiorespiratory fitness level. These associations are suggested mechanisms by which cardiorespiratory fitness reduces the risk of CVD and diabetes. Our findings support physical activity recommendations set forth by both the Surgeon General and the American College of Sports Medicine. This study was also in support of recommendations set forth by the ATP-III report to use physical activity as first-line therapy for the management of metabolic syndrome.

Significance to Preventive Care: Preventive Care Specialists often prescribe physical activity as a way of reducing chronic diseases such as cardiovascular disease and diabetes. Reducing hs-CRP via regular exercise may be an intervention by which exercise reduces risk of chronic disease. This study strengths the argument that regular physical activity reduces inflammation and metabolic syndrome risk factors thereby providing protection against the number one killer in the U.S., cardiovascular disease.

School

School of Public Health

First Advisor

Lee S. Berk

Second Advisor

Edward K. Fujimoto

Third Advisor

Wayne S. Dysinger

Fourth Advisor

Warren R. Peters

Degree Name

Doctor of Public Health (DrPH)

Degree Level

Ph.D.

Year Degree Awarded

2006

Date (Title Page)

6-2006

Language

English

Library of Congress/MESH Subject Headings

Metabolic Syndrome X -- prevention and control; Exercise -- physiology; Health Behavior; Life Style; C-Reactive Protein.

Type

Dissertation

Page Count

x; 97

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

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