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Publication Date

2012-07-05

Availability

UM campus only

Embargo Period

2012-07-05

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Psychology (Arts and Sciences)

Date of Defense

2011-04-05

First Committee Member

Patrice G. Saab

Second Committee Member

Maria M. Llabre

Third Committee Member

Judith R. McCalla

Fourth Committee Member

Frank J. Penedo

Fifth Committee Member

William K. Wohlgemuth

Abstract

The purpose of the current study was to examine the influence of physical activity, aerobic fitness, and sleep on metabolic syndrome and inflammatory outcomes. A sample of 367, 15-17 year old adolescents (73% boys) largely from ethnic minority groups (45.78% Hispanic, 30.79% Black), and the majority (72%) with systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) at or above the 90th percentile adjusted for gender, age, and height, underwent aerobic fitness testing (peak VO2 determined with maximal treadmill test), cardiometabolic risk factor blood sample drawing, and completion of behavioral questionnaires (7-day physical activity recall, Children’s Depression Inventory). Initially, we used confirmatory factor analysis and were successful in replicating findings of a hierarchical model with four first-order metabolic syndrome component factors (and their respective indicators) comprised of obesity (waist circumference and body mass index), insulin resistance (fasting glucose and insulin), lipids (high density lipoprotein and triglycerides), and blood pressure (BP; SBP and DBP), united under a common metabolic syndrome factor. Next, latent factors of sleep (7 nights of sleep duration and 1 composite sleep quality and fatigue score) and inflammation (C-reactive protein, interleukin-6, and fibrinogen) were added to the metabolic syndrome measurement model, which provided good fit. Finally, structural equation modeling was used to test direct effects of physical activity (kcal/kkg/day minus sleep duration), sleep, and aerobic fitness, as well as the indirect effect of physical activity and sleep through fitness, on the metabolic syndrome and inflammation, assuming a correctly specified model. Findings indicate that sleep loss (and poor sleep quality and fatigue) and decreased physical activity significantly predict increased risk of cardiometabolic outcomes through effects on reduced cardiorespiratory fitness in adolescents.

Keywords

cardiorespiratory fitness; behavioral factors; metabolic syndrome; inflammation; pediatrics

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