This dissertation aimed to investigate the direct and indirect pathways between body mass and three indicators of morbidity – health conditions, disability, and self-rated health status – and how these associations differed across birth cohorts. Using data from the Health and Retirement Study, a nationally representative longitudinal sample of adults age 51 or older, I used latent growth curve modeling to investigate the association of body mass on morbidity for five cohorts. Latent growth curve models allow for changes in body mass, health conditions, disability, and self-rated health over several waves of data to be assessed. To determine if the influence of education on health has declined, I also stratified each cohort by educational attainment groups. The results show that starting body mass is positively associated with starting health conditions; no other pathway examined was significant for all cohorts. In the three youngest cohorts, higher starting body mass was associated with worse self-rated health. Changes in body mass over time were not significantly associated with changes in self-rated health over time for the two youngest cohorts, perhaps indicating that adults at older ages do not perceive higher body mass as detrimental to overall well-being. Education was a significant predictor of body mass and self-rated health for all cohorts. When cohorts were stratified based on educational attainment, adults with at least some college had fewer health conditions than their less educated peers in all cohorts except the youngest cohort. The relationship between the rate of change in body mass and the rate of change in health conditions was not significant for the most educated group in the youngest cohort. However, higher starting body mass resulted in worse self-rated health regardless of cohort or education. Despite inconsistent findings, the results potentially support an expansion of morbidity because the onset of illness does seem to be occurring at younger ages. The effect of education on body mass and health was mostly consistent across cohorts. Stratifying the data by educational attainment suggests that the youngest and best educated cohort has not benefited from the increased level of education relative to the older cohorts in the study.

No description available.

Following bilateral lesions of the lateral hypothalamus animals are rendered completely aphagic and adipsic (Anand and Brobeck, 1951; Teitelbaum and Stellar, 1954). If not maintained by intragastric feeding, rats will eventually die of starvation and dehydration. However, if the animals are kept alive a gradual recovery of food and water intake will occur. This recovery period has been extensively and carefully studied, and four distinct recovery stages have been identified (Teitelbaum, 1961; Teitelbaum and Epstein, 1962). The first stage of recovery is characterized by the animal's refusal of all food and water. In the second stage wet and palatable foods are accepted, although not in sufficient quantities to maintain life. During the third phase, the animal is able to regulate its caloric intake on wet and palatable foods, but is unable to regulate its weight on dry food. Finally, in the fourth stage the lateral hypothalamic lesioned animal will accept dry food and water in sufficient amounts to maintain life.

Excess body fat, diabetes, and metabolic syndrome are associated with certain types of cancers. Although obesity is strongly associated with metabolic dysfunction (MetDys), some overweight individuals do not develop MetDys, although certain lean individuals do. The objective of this dissertation was to determine whether MetDys modifies the effect of excess body fat on cancer risk. The independent and combined effects of body mass index (BMI), waist circumference (WC), and MetDys on obesity-related cancer (ObCa) risk was examined among 3,818 45–69 year-olds in the Framingham Offspring Study using Cox proportional hazard’s analysis. Primary ObCa types included postmenopausal breast, endometrial, and colon cancer. Markers of MetDys included fasting glucose, triglycerides, high density lipoprotein-cholesterol, and hypertension. Subjects with ≥2 metabolic abnormalities were considered to have prevalent MetDys. Obesity alone (BMI≥30) in both men and women led to about a two-fold increased risk of ObCa. WC and waist-to-height ratio (WHtR) were somewhat stronger risk predictors in men than in women. There was little evidence of effect modification of WC or WHtR by MetDys in either men or women. In obese men, however, prevalent MetDys was associated with a 2.5-fold increased risk (95% CI: 1.36–1.46) of ObCa while obese men without MetDys had only a non-statistically significant 1.5-fold increased risk (0.70–3.03). There was no effect modification in women. To separate the effects of overall body fat from fat distribution, hip circumference was added to the multivariable models. Here, the effect of a WC >40 inches in men was strengthened (HR=2.59; 95% CI: 1.53–4.36) by controlling for HC. Conversely, when controlling for WC, the smallest HC in men conveyed a higher cancer risk (HR=2.68; 95%CI: 1.46–4.89). Subjects gaining ≥1 lb/year over approximately 14 years and who developed MetDys during that period had a 77% (95%CI: 1.21–2.59) increased ObCa risk while weight gainers not developing MetDys had a 31% (95%CI: 1.00–1.71) increased risk. Finally, weight gainers who became overweight/obese had a higher cancer risk than those with long-term overweight/obesity. This study suggests that those with excess body fat and long-term weight gain have higher ObCa risk, with little evidence that metabolic abnormalities modified the effect of obesity.

No description available.

<p>This thesis summarizes the findings of two studies, one qualitative and one quantitative, that examined the participation of adults with class III obesity in occupations of everyday living which included work, self-care, recreation and rest. The results of this research form the basis of the three manuscripts included in this thesis.</p> <p>The purpose of the first study was to describe the experience of living with obesity in the context of participation in daily activities and to identify factors that constrain or facilitate participation. Using a descriptive, phenomenological approach, in-depth, semi-structured interviews were conducted with 10 adults who were enrolled in an obesity treatment program. This analysis revealed themes that underscored the tensions, barriers and coping strategies across and within occupations of everyday living. The quality and diversity of occupation was influenced by several barriers within their environment such as inaccessible physical spaces and negative attitudes towards persons with obesity. Participants described their lives as being "on-hold" until weight was lost. Findings from this study were used to develop a larger, cross sectional survey.</p> <p>The purpose of the cross sectional survey (study number 2) was to describe how adults with class III obesity spend their daily time and to identify factors that predict participation in the occupations of everyday living. An analysis of data collected (n= 128) using the Occupational Questionnaire revealed that the distribution of time spent across activities classified as work, daily living, recreation and rest was similar to the time use of adults with chronic health conditions. A multiple regression analysis (n=140) resulted in a model in which factors including social support and disability status explained 35% of the variance in satisfaction with participation.</p> <p>Results of these studies contributed to a better understanding of the daily experience of participation in the occupations of everyday living for adults with class III obesity and the factors that best predict satisfaction with participation.</p> / Thesis / Doctor of Philosophy (PhD)

The aim of this thesis was to determine the synergistic effect of milk and exercise to: promote fat loss while maintaining protein balance and muscle; improve cardiovascular fitness and strength; and to evaluate the short-term adaptations of the inflammatory system and metabolic risk factors in overweight adolescents (boys ages 11-15 years, girls ages 9 to 13 years). A 7-day dietary intervention with 1-h intense exercise was used with randomization to milk (MILK: n=26, 8 male, 18 female) or carbohydrate beverage (CONT; n=29, 12 male, 17 female) post exercise. Both groups received a diet based on their resting energy expenditure. To determine whole body protein balance (WBPB), participants consumed 15N-glycine. Subjects performed a maximal cycling test to determine changes in power and 1-repetition maximum testing to determine changes in strength. Blood was taken to evaluate glucose and insulin; tumour necrosis factor-alpha (TNF-α), interleukin-6 and c-reactive protein ; and blood pressure was measured pre and post intervention. Although body weights did not change, the MILK group maintained more muscle (-0.2 ± 0.6 vs. -0.7 ± 0.8 kg, p<0.01) and had a greater loss in body fat (-0.4 ± 1 vs. 0.5 ± 1.0 %, p<0.006). The changes in body composition were supported by a greater WBPB after training in the MILK group (1.64 ± 1.1 vs. 0.84 ± 0.6, p<0.001). Power increased only in the MILK group with an increase of 0.13 watts/kg (p<0.05) with an increase in V02max that approached significance (p=0.06). Improvements in strength and the blood risk factors were not different between the groups. There was a greater decline in mean arterial pressure in the MILK group (-3 ± 6 mmHg vs. 2 ± 7 mmHg, p< 0.04). The exercise intervention led to an increase in TNF-α in both groups (0.3 ± 0.7 pg/ml vs. 0.5 ± 0.7 pg/ml, p<0.001). These data support the consumption of milk after exercise in the early stages of pediatric obesity treatment. / Thesis / Doctor of Philosophy (PhD) / The aim of this thesis was to determine if milk and exercise work together to: promote body fat loss while maintaining protein balance and muscle in overweight adolescents; increase fitness and strength; and assess changes in inflammatory markers and disease risk factors. A 7-day diet with 1-hour exercise sessions was performed with milk or a carbohydrate drink. Protein balance was measured by a urine marker. Pre and post the following measures were used: cycling test for power; weight lifting test for strength; blood for disease markers; and blood pressure. After the week, the milk group were in a more positive protein balance, maintained more muscle, had a greater loss in body fat, greater increase in power and lower blood pressure compared to the carbohydrate group. Some of the inflammatory markers increased in both groups. Exercise combined with the nutrients from milk can have a positive effect on adolescent health.

This work contains a summary of the current genetic, epigenetic and metagenomic knowledge of obesity, as well as an extensive overview of current genetic approaches in mouse models of obesity. Lastly, this work presents a candidate gene approach based on mouse models, which finds new variants associated with multiple obesity phenotypes in a multi-ethnic cohort. / The prevalence of obesity has been mainly be attributed to the rise in an obesogenic environment, in which individuals are more prone to high-dense energy foods and live a sedimentary lifestyle. Familial aggregation of obesity however, has led to numerous studies focused on understanding the genetic basis of this complex disorder. To this effect, this thesis summarizes the current knowledge of obesity genetics, including the monogenic, polygenic and epigenetics field. Given the tremendous contribution of animal models, especially mouse models, to our current knowledge of obesity genetics, this thesis summarizes the methodology of genetic studies in mice, and focuses on how the synergy between human and mouse studies has led to not only the discovery of obesity causal genes, but also their biological contribution to obesity. Lastly, this thesis summarizes a candidate gene approach based on the information from mouse models that have led to identification of a novel variant associated with body mass index (BMI), hip circumference and body adiposity index (BAI) in a multi-ethnic cohort. / Thesis / Master of Science (MSc) / Obesity is a heritable disease, and the genetic basis of obesity could result in better prevention and treatment options for this disorder. Obesity patterns are not uniform worldwide, and some ethnic groups are more prone to obesity than others, therefore having a multi-ethnic approach in studying obesity could yield to causal variants that could be generalized to all.

In individuals living with obesity, adipose tissue aids in reducing (H_loss) and also serves as a heat storage compartment. Moreover, lean body mass, which has a higher H_prod than adipose tissue plays a crucial role in energy production and thermoregulation. The extent of resistance to the cold remains underexplored in this population, and it is important to understand these responses given the global obesity rise and its health implications. This study aimed to quantify how various body anthropometric variations affected thermal responses in individuals living with obesity during acute compensable cold exposure. A liquid-conditioned suit, connected to a temperature-controlled water circulating bath set at 10°C, was used for 90 min to elicit a compensable cold response in these individuals. Validated methods regarding subjective thermal comfort and sensations, skin temperature (T_skin; °C), heat production (H_prod; kJ ⋅min⁻¹), metabolic fuel selection and shivering intensity were recorded to determine the effect of obesity (and muscle and fat mass) on thermogenic and thermal responses. Our study revealed that individuals with obesity, like their lean counterparts, manifest an increased H_prod during cold exposure by 1.7 ± 1.3 kJ ⋅min⁻¹. However, this increase was observed to be lesser in magnitude among individuals living with obesity compared to lean ones. We also explored the source of fuel during cold exposure and found that carbohydrate and lipid oxidation collectively accounted for a significant proportion of H_prod, with lipid oxidation dominating at 61%, and carbohydrates at 21%. Regarding muscle activity, it was observed that a decrease in T_skin incited an increase in shivering. However, similar to the metabolic responses, shivering in this cohort was much less pronounced than in lean individuals. The study opens avenues for further research, addressing the implications of repeated cold exposure and different lengths, temperatures, or modalities on individuals living with obesity.

Since few studies exist that examine the relationships between adolescent obesity and academic performance, the purpose of this study was to examine the impact of obesity on high school students’ academic performance in a low socioeconomic school district. The topics addressed in this study included prevalence of overweight and obesity in high school students and the impact of overweight and obesity on student academic performance. The potential population of this study consisted of 236 high school students aged 14 to 19 years old enrolled in a rural Mississippi school district in grades 9 -12. However, only 35 students had usable data in all of the categories that were examined, and, therefore, were used as the population for the final analysis. The participants studied in this study consisted of all students assigned to one physical education teacher. Each student was administered the Project Health Student Measurement Chart which was developed by Project Health, a research entity of the Institute of Epidemiology, Jackson State University, Jackson, Mississippi. The Project Health Student Measurement Chart was utilized to enable the participating students to be examined on characteristics that included Body Mass Index (BMI), blood pressure and pulse rate. Student information collected on their obesity status based on BMI level was also collected in this study. In addition, the students’ performances on subject area tests and/or end-of-course assessments in the academic areas of Algebra I, English II, Biology I, and U.S. History from 1877 were accessed from the school’s records. Based on the results of this study, 48.60% of the students in the Canton Public School District are overweight/obese. However, the findings of this study revealed that there was no significant difference between overweight/obese and non-obese students’ academic performance on subject area tests and/or end-of-course test by age, gender and grade, and no significant relationships in the academic performance of overweight/obese and non-obese students on end-of-course test scores for 10th – 12th grades, as measured by Algebra I, English II, Biology I, and US History from 1877.