Thesis (Ed. D.)--University of North Texas, Aug., 2009. / Title from title page display. Includes bibliographical references.

Source: Masters Abstracts International, Volume: 47-06, page: 3557. Adviser: Arnold J. Schecter. Includes bibliographical references.

Background: Childhood obesity remains a major public health concern. While preventing childhood obesity is important, the effectiveness of existing prevention strategies is indefinite. Important obesity contributors are speculated to be overlooked while the role of well-studied obesity-related factors has been questioned. Objectives: 1) Although the association between lifestyle and obesity is seemingly well-established, how an overlooked dietary factor, breakfast location, associates with obesity was investigated 2) At a time where inconsistencies in findings for the frequently studied association between TV viewing and obesity still exist, this thesis tested for the existence of the said association in the understudied Chinese population 3) The effect of mental health on childhood obesity is understudied. Using self-esteem as a mental health indicator, the effect of self-esteem on childhood obesity was investigated To understand the role of lifestyle factors in the association between self-esteem and obesity, how 4) breakfast habit and 5) TV viewing habit associates with self-esteem was explored Methods: A cohort of 83405 primary 4 (P4) Department of Health Student Health Service participants (49.7% male, mean age 9.9 years) in 1998-2000 were successfully tracked for 2 years into primary 6 (P6). A self-administered health questionnaire collected information on the breakfast and TV habits of participants alongside other lifestyle characteristics. Self-esteem was assessed using the four Culture Free Self-Esteem Inventories for Children (SEI) subscales. Body mass index (BMI) was derived using objectively measured weight and height. Weight status was classified in accordance to International Obesity Task Force standards. Logistic, multinomial logistic and linear regression were used to yield adjusted odds ratios (AOR) and β-coefficients for becoming overweight/obese in P6 (among P4 normal weight children), breakfast skipping/location, TV viewing habit and SEI subscale scores. Breakfast skipping behaviour was tested as a mediator in the association between self-esteem and obesity using standard mediation procedures. Breakfast and TV viewing habits were tested as effect modifiers in the same association by inclusion of interaction terms in models. Results: Among normal weight P4 children, those who skipped breakfast (AOR: 1.24; 95% CI: 1.02 to 1.51) or ate away from home (1.39; 1.20 to 1.60) were more likely to become overweight/obese in P6. Poor self-esteem was also associated with higher AORs for becoming overweight/obese, particularly among girls. While TV viewing in P4 did not predict overweight/obesity in P6, those who increased TV watching hours (≤2h/day to 2h/day) during the two follow-up years were 32% more likely to become overweight/obese in P6 than their counterparts who maintained watching ≤2h/day. Breakfast habit and self-esteem was bi-directionally associated. Although a curvilinear inverted J-shaped relation between P4 TV viewing and P6 self-esteem was observed, self-esteem did not predict TV viewing habit. While neither breakfast nor TV viewing habit significantly interacted with self-esteem to predict obesity, breakfast skipping was found to be a potential partial mediator in the association between self-esteem and obesity. Conclusion: Breakfast location, self-esteem and TV viewing patterns over time are important to consider in relation to childhood obesity. Additionally, the association between self-esteem and obesity could be mediated by lifestyle factors. / published_or_final_version / Community Medicine / Doctoral / Doctor of Philosophy

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Worldwide, overweight/obesity and associated chronic diseases such as type 2 diabetes, have reached epidemic proportions. Statistics show that overweight/obesity and chronic disease is prevalent amongst adults and children in South Africa. In addition to chronic disease/non-communicable diseases, overweight/obesity has been shown to alter immune and sympathetic activation. There is limited information on immune function (mucosal) and sympathetic activation on children both internationally and nationally and in particular investigating these parameters using non-invasive methods such as salivary biomarkers. The aim of this thesis was to investigate the levels of salivary biomarkers of immune function and sympathetic activation in children and determine the association with overweight/obesity, cardiorespiratory fitness (CRF) and increased physical activity (PA). Methods This thesis is divided into six chapters. These include an introductory chapter (Chapter One), a review of the literature (Chapter Two) and then three chapters that are written in article format and that have each been submitted to accredited journals for publication. Chapter Three is a review article that discusses salivary biomarkers in children as they relate to exercise, PA and obesity. Chapter Four is a study that examined salivary biomarkers of mucosal immunity and sympathetic activation as predicted by age, body composition and cardiorespiratory variables in one hundred and thirty-two black South African children (age 10.05 ± 1.68y, 74 females, 58 males). Chapter Five is a study that investigated salivary biomarkers of mucosal immunity and sympathetic activation in response to 12 weeks of soccer training in thirty-four black male South African children (11 – 13y) from a youth football training academy. Chapter Six includes a summary of the research findings, conclusions and well as recommendations for future research. A review of the literature revealed that participation in regular moderate intensity PA or exercise appears to enhance mucosal immunity (increases salivary IgA (sIgA)) in preadolescent children. In contrast, poor fitness and inactivity as well as strenuous training appear to compromise the mucosal immune system thereby increasing the risk of upper respiratory tract infections (URTIs). Children reporting higher levels of body fat and with a greater BMI appear to have lower sIgA levels and a greater incidence of infections. The limited research examining salivary C-reactive protein (sCRP) suggests a strong association between poor cardio-respiratory fitness (CRF) and/or overweight/obesity and inflammatory status in children based on elevated sCRP levels. Research surrounding salivary alpha-amylase (sAA) indicates that exercise can result in a marked increase in sAA as seen by an increase sympathetic activity via increased adrenergic activity in the salivary glands. The limited research suggests exercise may also pose a high stress on young athletes as seen with an increase in sAA. Additionally it appears that BMI may be a strong predictor of stress-induced sAA increases in children. Greater hypothalamic pituitary adrenal (HPA) axis response, as seen by increases in salivary cortisol, appear to be influenced greatly by increases in obesity. Higher salivary cortisol secretions have been observed in obese versus lean children in response to exercise. School study: The outcomes of the one-way ANOVAs examining the differences by body mass index (BMI) categories showed there were significant differences in weight (F = 83.64, df = 2, 129, P < 0.0001), BMI (F = 193.36, df = 2, 129, P < 0.0001), waist-to-hip ratio (F = 193.36, df = 2, 129, P < 0.0001), body fat percentage (F = 336.98, df = 2, 129, P = 0.0001), SBP (F = 5.72, df = 2, 129, P = 0.0042), DBP (F = 291.76, df = 2, 129, P < 0.0001), VO2max (F = 521.00, df = 2, 129, P < 0.0001), sAA concentration (F = 17.05, df = 2, 129, P < 0.0001), sAA secretion rate (F = 15.15, df = 2, 129, P < 0.0001), sIgA concentration (F = 11.30, df = 2, 129, P < 0.0001), and sIgA secretion rate (F = 8.08, df = 2, 129, P = 0.0005), between children of different BMI categories. According to the CDC-BMI-for-age standards, the participants were grouped into the following CDC-BMI-for-age categories: normal weight (< 85th percentile), overweight (≥ 85th percentile to < 95th percentile), and obese (≥ 95th percentile) (Ogden and Flegal, 2010). Tukey’s post hoc analyses revealed that obese children had significantly (P < 0.01) higher weight, BMI, body fat percentage, DBP, SBP, sAA concentration and secretion rate, compared to overweight and normal weight children, as well as a significantly lower aerobic capacity (VO2max) than both normal (P < 0.001) weight and overweight (P < 0.05) children. In addition, sIgA concentration and secretion rate were significantly lower between normal weight and obese children (P < 0.01). Multiple linear regression revealed that BMI, DBP and VO2max predicted sAA. BMI (P = 0.04) and DBP (P = 0.04) were found to be independent predictors of sAA concentration. Age and BMI category predicted sIgA secretion rate. BMI category (P = 0.0006) was found to be an independent predictor of sIgA secretion rate. Soccer study: Significant differences after 12 weeks of soccer specific training were found to be significant between pre vs. post for BMI (P =0.034), waist-to-hip ratio (P = 0.046), age (P < 0.0001), height (P < 0.0001), body fat % (P < 0.0001) and LMM (P < 0.0001). Decreases in BMI, waist-to-hip ratio, body fat % and LMM were found while age and height increased throughout the 12 weeks. Significant differences were also found between sIgA secretion rate pre vs. post training (P =0.025) as increases in these values pre to post were observed. Conclusions The results from the studies on the school children and soccer players suggested that mucosal immune function and sympathetic activation appear to be affected by body composition, CRF and chronic exercise training. The main findings for the school study revealed that BMI, DBP and VO2 predict sAA and that age and BMI category predict sIgA. This study also found that obesity (based on BMI) has a major role to play and that obese children have elevated sAA, lowered sIgA, and poor CRF. The finding of an increase in sIgA secretion rate in the soccer study suggested that a structured 12 week exercise programme can elevate mucosal immune function in youth soccer players. The underlying mechanism responsible may be an exercise-induced increase in the transport of sIgA across the mucosal epithelium and/or enhanced production of IgA in the mucosa via mediating cytokines. The literature review demonstrated that PA and overweight/obesity may have an impact on salivary biomarkers of mucosal immunity and sympathetic activation in children, however further research with regards to optimal intensity, duration and modality need to be assessed in the pre-pubescent population.Physical activity, obesity, immunity, neuro-endocrine, children, salivary biomarkers, sympathetic activation. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2012.

Thesis (M.P.H.)--Georgia State University, 2007. / Title from file title page. Russ Toal, committee chair; Michael Eriksen, Valerie Hepburn, committee members. Electronic text (102 p. : ill. (some col.)) : digital, PDF file. Description based on contents viewed Mar. 26, 2008. Includes bibliographical references (p. 71-73).

Thesis (M.S.)--University of Texas at El Paso, 2008. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

Thesis (M.Sc.). / Written for the School of Dietetics and Human Nutrition. Title from title page of PDF (viewed 2009/06/19). Includes bibliographical references.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2009. / Title from title screen (site viewed February 25, 2010). PDF text: x, 171 p. : col. ill. ; 5 Mb. UMI publication number: AAT 3386558. Includes bibliographical references. Also available in microfilm and microfiche formats.

Thesis (M.S.)--Ohio University, March, 2009. / Title from PDF t.p. Includes bibliographical references.