Introduction: Approximately 3 million child maltreatment (CM) referrals are made each year to state and social service agencies (U.S. Department of Health and Human Services- Children’s Bureau, 2012). This number appears to be an underestimate of the size of the problem however. Survey data collected by the Children’s Bureau of the U.S. Department of Health and Human Services estimates that about six million children are maltreated in the U.S. per year. CM negatively impacts the mental and physical health and social outcomes of victims in childhood and adulthood. For example, CM has been linked to obesity and overweight in children and adults. Similar to CM, overweight and obesity are also associated with various long-term and short-term health conditions for children and adults. Beyond the specific provision of food and modeling of eating and exercise behaviors, other family factors have been shown to relate to obesity including disorganized family environments, low parental supervision, maternal antipathy, child maltreatment, and family dysfunction. Objective: To examine the relationship between CM and obesity using a large sample of twin and sibling pairs, I will first examined the simple relationship between various form of abuse and obesity, and then, following the methodology of Vámosi et al. (2011), examine twin and sibling pairs to look at differences in experiences of CM and obesity. Methods: The current study used the Midlife Development in the United States (MIDUS), a public use longitudinal data set with information in the areas of physical, emotional/mental, and lifestyle characteristics of individuals in their 20’s, 40’s, and 60’s. The data set also includes nationally representative data about sibling and twin pairs. The MIDUS I had a sample of 7,108 participants. The MIDUS II was a follow-up of the MIDUS I and included 4,963 participants. The main variables I used were Body Mass Index (BMI) and CM, which was measured through the Conflict Tactics Scale. I controlled for various variables that contribute to overweight or obesity, such as socioeconomic status, educational attainment, physical activity, and depression. The comparison of twin and non-twin sibling data was of particular interest because of the strong genetic component of obesity. Results: Analyses were conducted using SPSS. I first examined simple correlations between abuse variables and obesity. Next, I conducted regression analyses examining the relationship between abuse and obesity, while controlling for gender, educational attainment, age, and several other variables associated with CM and obesity. The third analyses focused on examining differences in the abuse – obesity relationship between twin and sibling pairs. There was a small, negative relationship between BMI continuous and emotional abuse and physical abuse. There was a small, positive relationship between each form of abuse and BMI categories. Discussion: Although statistically significant results were found, they were small. The relationship between obesity and overweight and experience of CM is valid after controlling for various predictors, like health insurance, depression, and self-rated physical and emotional health. Public health practitioners should be sensitive to the physical health of victims of CM, especially concerning obesity and overweight. Many public health practitioners focus on the mental and emotional health of victims of CM, but they should also be made aware of the impact that CM has on physical health. There are several limitations. Regarding the CM variables, participants may have had difficulties recalling events from their childhood, so recall bias is a major limitation. Another limitation is that much of the data is self-reported which could have led to some data, like BMI, being inaccurate. Finally, we do not know the quality of the phone interviews or how well phone interviewers were trained.

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Research regarding childhood obesity in Canadian children has failed to address the effects of immigration on weight status. This study examined correlates of obesity and overweight including family functioning, parenting style (consistent parenting, positive interactions, hostile interactions, and punitive parenting), neighborhood conditions, physical activity, and screen time in immigrant children (i.e., children not born in Canada but currently residing in Canada). Correlates of obesity were examined using the National Longitudinal Survey of Children and Youth (NLSCY), a nationally representative data set with several waves of data collection, conducted from 1994 to 2008. The correlates were analyzed using multiple regression models. Neighbourhood factors, family functioning and other parenting factors such as: hostile interaction, positive interactions, punitive parenting and consistent parenting, were not associated with BMI or obesity and overweight status. Contrary to previous findings, time spent in Canada was not associated with physical activity or screen time among immigrant children. None of the variables investigated were significantly associated with obesity and overweight status. This lack of significant findings may have been due to small immigrant sample sizes, inadequate or limited measures of confounding variables; such as macronutrient composition of diet that could not be accounted for in our analysis. However, given that models were run using both logistic and linear regression and results were consistent across the board, there may well have been no relationship between these variables. Findings were non-significant and therefore conclusive findings and recommendations could not be drawn from this study

Obesity is a complex disorder which has become a growing health concern. Twin studies have demonstrated a strong genetic component to the development of obesity and genome wide association studies have identified several genetic loci associated with it. However, most of these loci are still poorly understood in a functional context. Interestingly, many of the hormones and neurobiological messengers responsible for regulating feeding behaviour and metabolism are also linked to controlling aggression, but it is still not understood how they interact to maintain metabolic homeostasis. In this thesis, the model organism Drosophila melanogaster was employed to dissect the molecular mechanisms of the genetic cascades regulating aggressive behaviour and metabolic homeostasis. In paper I and II, the role of transcription factor AP-2 (TfAP-2) and Tiwaz Twz, Drosophila homologues of two human obesity-linked genes were investigated in aggression and feeding behaviour. Paper I demonstrated that TfAP-2 and Twz genetically interact in octopaminergic neurons to modulate male aggression by controlling the expression of genes necessary for octopamine (fly analogue of noradrenaline) production and secretion. Moreover, it was revealed that octopamine in turn regulates aggression through the Drosophila cholecystokinin (CCK) satiation hormone homologue Drosulfakinin (Dsk). Paper II revealed that TfAP-2 and Twz also initiate feeding through regulation of octopamine poduction and secretion. Octopamine then induces Dsk expression leading to inhibition of feeding. Paper III established that the activity of the small GTPase Ras-related C3 botulinum toxin substrate 2 (Rac2) is required in Drosophila for the proper regulation of metabolic homeostasis, as well as overt behaviours. Rac2 mutants were starvation susceptible, had less lipids and exhibited disrupted feeding behaviour. Moreover, they displayed aberrant aggression and courtship behaviour towards conspecifics. Paper IV studied Protein kinase D (PKD), the homologue of a third obesity-linked gene PRKD1, and another kinase Stretchin-Mlck (Strn-Mlck). Reducing PKD transcript levels in the insulin producing cells led to flies with increased starvation susceptibility, decreased levels of lipids and diminished insulin signalling compared to controls. Reduced Strn-Mlck expression resulted in a starvation phenotype and slight reduction in insulin signalling and lipid content. These findings imply a function for PKD and Strn-Mlck in insulin release.

The failure to maintain a healthy lifestyle (particularly consuming a healthy diet and engaging in regular physical activity) is a significant contributor to overweight and obesity and the resulting detrimental effects on individual and public health. Using Social Cognitive Theory and the Health Action Process Approach to inform the theoretical framework, this research examined whether maintaining a healthy lifestyle is influenced by different factors in overweight or obese and normal weight groups. Participants were 374 University students, categorized as overweight or obese and normal weight based on BMI determined by self-reported height and weight. They were assessed on measures of healthy eating and physical activity (at three-month intervals, to determine the maintenance of those behaviours over time) and variables predicted to influence those behaviours including: action self-efficacy, outcome expectations, intentions, planning, recovery self-efficacy, facilitators (i.e., consideration of future consequences, perceived social support and perceptions of general health) and impediments (i.e., depression, perceived stress and shame). Structural Equation Modeling was used to determine the fit of the predicted model for the total sample and for the overweight and obese and normal weight subgroups. The results demonstrated that a revised model predicting exercise behaviour (but not healthy diet) was able to adequately explain the data for the overall sample and for the normal weight subsample, but not for the overweight and obese subsample. Outcome expectations about exercise, self-efficacy and planning made important contributions to the prediction of exercise behaviour, but not diet. Implications of these findings will be discussed.

This study examined the effect of varying levels of competence and warmth portrayed by an obese woman, on the evaluation of obese individuals in general. The Stereotype Content Model (SCM) provided a theoretical basis for the four interventions and one control group tested in this study. The interventions involved presenting, either online or in-person, a vignette of an obese woman with varying levels (high versus low) of competence and warmth to 400 first year university students. Several measures were used to evaluate feelings, attitudes, stereotypes, and levels of perceived competence and warmth both prior to receiving the intervention and at three follow-up times. Results revealed significant effects of the warmth intervention on measures of competence and warmth at the post-test 1 time, and of the warmth intervention on measures of competence in examining changes over a two-week time period. Results also showed significant effects of presentation condition, the most interesting finding being that those in the online condition reported the greatest decrease in negative stereotypes and evaluations. Limitations of this study including design flaws are identified, as are suggestions for future research, and implications of these findings.

Background: Obesity is associated with conditions that may affect Canadians’ health status and strain the health care system. Obese individuals are subjected to stigmatization. Most public health programs to date promote weight loss. However, weight loss is rarely sustainable. Insight must be gained into the embodied, lived experiences and lifestyles of ‘target’ populations and their perceptions of and priorities concerning health and wellbeing to develop public health programs that enhance lifestyles and health. Purpose: The purpose of my research was to use critical ethnographic research methods to explore obese individuals’ perceptions of health and obesity and the impact of these assessments, as well as personal weight trajectories, on obese individuals’ health perceptions, lifestyles, quality-of-life, and behaviours. Methods: This study involved one- year ethnography. Data sources included field notes and repeated (every 3-4 months), audio-taped, semi-structured, qualitative interviews with research participants. Subsamples included obese and formerly obese individuals who were 1) pursuing weight loss to achieve health goals, 2) attempting to maintain weight loss, and 3) attempting to get/stay healthy through diet and exercise but were not concerned with weight loss. Participant observation occurred at sites identified by participants as essential to their embodied, lived experience. Results: Three major themes emerged: the importance of function to health and quality-of-life; compulsion, addiction, and the need for validation; and social impacts of various weight trajectories and perspectives. Participants recounted multiple ways in which their ever-fluctuating bodies and related bodily attitudes profoundly affected their social lives and the degree of social acceptance they experienced in coping with their bodies, participants often described highly compulsive food, dieting, and fitness behaviours and a constant search for validation of their health-related endeavours. Significance: The dominant discourse regards obese individuals as ill. This perspective may produce disempowering public health initiatives. To achieve sustainable benefits for Canadians’ quality-of-life, a greater understanding of what constitutes health and wellbeing for obese individuals, and how such factors may change over time and differing circumstances, is essential. This insight will contribute to a salutogenic and holistic approach to health, particularly in populations that may feel stigmatized as a result of health issues.

Metabolic Syndrome (MetS) is an obesity-related disorder that predisposes an individual to several life-threatening diseases such as cardiovascular disease, hypertension and type 2 diabetes mellitus. The diagnosis of metabolic syndrome is based on the presence of at least 3 of the following 5 risk factors: elevated triglycerides, high blood pressure, high blood glucose, low HDL cholesterol and central adiposity. However, the biochemical mechanisms underlying the contribution of these irregularities are not fully understood. Currently, there is a need to better characterize MetS. Irregularity of lipid abundances, dyslipidemia, is known to be associated with MetS. However, little is known about the link between plasma phospholipids and human metabolic syndrome. In this study, mass spectrometry-based metabolomic approaches were employed using ultrahigh-resolution FTICR mass spectrometry to qualitatively analyze human plasma phospholipids and high-resolution QTOF mass spectrometry to quantitatively detect differences in the human plasma phospholipid profiles from 10 clinically-diagnosed metabolic syndrome patients and 8 lean healthy controls. The results point to the existence of a phospholipid signature of MetS. Five of the top twenty phospholipids contributing most to the difference in phospholipid abundance between the MetS and control group were identified using accurate mass-based database searching and MS/MS for structural confirmation. Relative differences in phospholipid abundances between MetS and controls for all top 20 phospholipids were shown to be statistically significant. These results may aid biomarker discovery and the accurate evaluation and prevention of diseases associated with dyslipidemia including human metabolic syndrome. / Graduate