Background: Abdominal obesity (AO) is associated with
cardiometabolic risk. In 2003-
2004, more than 50% of adults had AO. Psychological distress, through hypothalamic-
pituitary-adrenocortical (HPA) axis activation with increased dietary energy density
(ED), may contribute to AO.
Purpose: To examine ED and HPA activation as mediators between psychological
factors and AO in overweight adults. This study was guided by the adapted Stress and
Methods: Descriptive, cross-sectional design was used to enroll 87 adults, with a mean
age of 41.3 + 10.2 years; mean body mass index (BMI) of 32.1 + 6.1 kg/m2; 73.6%
women; 50.6% African-Americans. Participants completed the Beck Depression
Inventory-II (BDI-II), Perceived Stress Scale (PSS) and Three Factor Eating
Questionnaire Revised (TFEQR) to measure depressive symptoms, perceived stress and
dietary restraint. They completed a weighed three day food record which was analyzed
for caloric intake and food and beverage weight, and ED (kilocalories/gram) was
calculated. Participants collected saliva samples for cortisol. Height, weight were
measured to calculate BMI, and waist circumference (WC), an indicator of AO, was
measured. Descriptive statistics and sequential regression were used to predict WC.
Three approaches evaluated ED as a mediator between psychological factors and
cardiometabolic disease risk.
Findings: Increased depressive symptoms (p above that explained by younger age (p=.06), male gender (p=.06), African-American
race (p (p food and beverage weight (p was significant (p=.04) explaining 4.0% of WC variance. Increased BDI-II (p=.05)
explained WC variance above that explained by older age (p=.23) and low dietary
restraint (p=.21). Morning salivary cortisol did not explain variance in food and
beverage ED or WC. There was insufficient evidence to conclude food and beverage
ED or morning salivary cortisol were mediators.
Conclusions: Increased depressive symptoms independently predicted high food and
beverage ED and elevated WC. Food and beverage ED independently predicted
elevated WC. Whether a reduction in depressive symptoms alters dietary ED, and if a
reduction in dietary ED reduces WC, merit further evaluation.
Table of Contents
ABSTRACT ACKNOWLEDGMENTS TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES CHAPTER I 1 Introduction 1 Statement of the Problem 1 Specific Aims and Hypotheses 3 Conceptual Framework 4 Overview 4 Theoretical Assumptions 9 Individual Characteristics 9 Environmental Demands 11 Psychological Factors 12 Possible Biobehavioral Mediators 12 Blood Glucose and the Metabolic Regulating Hormones 14 Cardiometabolic Disease Risk 14 Conceptual and Operational Definitions 15 Significance of the Proposed Study 18 Summary 19 CHAPTER II 21 Review of the Literature 21 Introduction 21 Individual Characteristics 21 Age, Gender, Race/ethnicity and Psychological Distress 21 Age, Gender, Race/ethnicity and Abdominal Obesity 22 Dietary Restraint 24 Overweight 25 Physical Activity 26 Smoking 28 Alcohol Use 29 Genetic Factors 31 Environmental Demands 32 Psychological Factors 34 Biobehavioral Responses 36 Hypothalamic-Pituitary-Adrenocortical Activation 36 Dietary Pattern 43 Glucose and the Metabolic Regulating Hormones 54 Glucose, Insulin and Glucagon 54 Leptin 55 Cardiometabolic Disease Risk 60 Adiponectin 62 Endocannabinoid System 63 Summary 64 CHAPTER III 66 Methodology 66 Introduction 66 Research Design 66 Design 66 Setting and Sample 67 Sample Size 69 Recruitment 69 Pilot Study 70 Background and Purpose 70 Conceptual Model 70 Sample and Methods 71 Results 72 Conclusions and Implications 73 Variables and Measures 74 Participant Screening Form 74 Anthropometric Measurement Form 74 Demographic and Clinical Data Forms 75 Weighed Three-Day Food Record 76 Three Factor Eating Questionnaire Revised (TFEQR) 78 The Beck Depression Inventory II (BDI-II) 78 Perceived Stress Scale (PSS) 79 Cortisol Secretion 80 Procedure 81 Data Analysis 84 Data Management Plan 84 Data Analysis Procedures 89 Additional Analysis 97 Summary 98 CHAPTER IV 99 Results 99 Introduction 99 Description of the Sample 99 Demographic Characteristics of the Sample 99 Clinical Characteristics of the Sample 100 Individual Behavioral Characteristics of the Sample 103 Environmental Factors 106 Psychological Factors 106 Dietary Pattern 107 Biobehavioral Mediators 112 Waist Circumference 117 Reliability of Study Instruments 120 Specific Aim 1 121 Hypothesis 1 121 Hypothesis 2 127 Specific Aim 2 129 Hypothesis 3 129 Hypothesis 4 134 Specific Aim 3 137 Hypothesis 5 137 Hypothesis 6 142 Additional Analyses 147 Summary 149 CHAPTER V 153 Discussion 153 Introduction 153 Summary of Results 153 Demographic and Clinical Characteristics 153 Behavioral Characteristics 154 Environmental Factors 155 Psychological Factors 155 Dietary Pattern 156 HPA Activation 159 Findings 159 Specific Aim 1 159 Specific Aim 2 160 Specific Aim 3 161 Implications for Theoretical Framework 162 Psychological Factors and Biobehavioral Mediators 163 Biobehavioral Mediators and Cardiometabolic Disease Risk 167 Psychological Factors and Cardiometabolic Disease Risk 174 Methodological Issues 176 Study Limitations 179 Study Strengths 182 Recommendations for Research 183 Recommendations for Clinical Practice 191 Summary 195 REFERENCES 197 APPENDIX A 234 Multiple Regression Power Analysis 234 APPENDIX B 236 IRB Approval Letter 236 Amendment 1 Approval 238 Amendment 2 Approval 240 Amendment 3 Approval 242 2008 Continuing Review Approval 244 2009 Continuing Review Approval 246 APPENDIX C 248 Telephone Screening and Verbal Permission Form 248 Anthropometric Measurements Form 252 Procedures for Anthropometric Measurements 253 Health History Form 262 Medications 263 Vitamin or Other Supplements 264 Three Day Food Record 265 How to Keep a Three-Day Food Record 268 Three Factor Eating Questionnaire Revised (TFEQR) 269 Beck Depression Inventory-II 273 Perceived Stress Scale 280 Saliva Collection Cards 282 APPENDIX D 284 Data Table 284 APPENDIX E 287 Additional Analyses Related to Specific Aim 1 287 Additional Analyses Related to Specific Aim 2 293
About this thesis
|Committee Chair / Thesis Advisor|
|Energy Density of Food Intake in Overweight Adults ()||2018-08-28||