4. Electronic Theses and Dissertations (ETDs) - Faculties submissions
Permanent URI for this communityhttps://hdl.handle.net/10539/37773
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Item Adolescent health in rural South Africa: building an evidence-base to inform a health promotion intervention supporting healthier lifestyles(University of the Witwatersrand, Johannesburg, 2024) Seabi, Tshegofatso Martha; Kahn, Kathleen; Wagner, Ryan GBackground Low- and middle-income countries (LMICs), including South Africa, face the persisting double burden of malnutrition, with undernutrition and overnutrition coexisting within the population. This issue is particularly pronounced among rural adolescents, who experience limited access to healthcare services, inadequate infrastructure, poverty, and a scarcity of nutritious foods. Addressing this double burden of malnutrition is essential for improving the health outcomes of rural adolescents and breaking the intergenerational cycle of malnutrition. Community health worker-led interventions have shown promise in promoting healthier lifestyles in this population, making it crucial to understand the feasibility and acceptability of such interventions. Aim This thesis aims to provide context-specific information on the changing distribution of Body Mass Index (BMI) and views on obesity among rural South African adolescents to inform the development of a targeted behaviour change intervention. Furthermore, it seeks to determine the feasibility, acceptability, and overall experience of implementing a complex intervention aimed at promoting healthier lifestyles in this population. Methods Using a mixed methods approach focusing on adolescents 12-20 years of age living in rural South Africa. This work is nested within the MRC/Wits rural public health and health transitions research unit (Agincourt) Health and Demographic Surveillance System, which is where the sample was drawn and provided explanatory variables such as SES. This work includes data from two studies with comparable measures, conducted in 2007 (n= 1309) and in 2018 (n=518), this study analysed comprehensive data on the prevalence and trends of BMI, including both undernutrition and overweight/obesity, among rural adolescents in 2007 and 2018. This was done through weight and height measures. Growth z-scores were used to determine stunting, underweight and overweight and overweight/obesity was generated using the 2007 WHO growth standards for adolescents aged up to 17 years and adult cut-offs of BMI of <=18.5 for underweight and =>30 kg/m2 for overweight and obese respectively for adolescents 18 to 20 years. Qualitative data was collected in the form of focus group discussions and in-depth interviews. Pre-intervention, three focus group discussions were held with male (n = 16) and female adolescents (n = 15) focusing on obesity to capture views, attitudes and perceptions surrounding obesity. Post-interventions, six focus group discussions were held with male and female adolescents. In-depth interviews were conducted with adolescents (n=20), parents (n=5) and CHWs (n=3), focusing on the feasibility and acceptability of the health promotion intervention. All qualitative data were analysed using inductive thematic analysis. Results This study found that there is a persistent double burden of malnutrition amongst rural adolescents. The pattern of underweight and overweight/obesity remains similar between 2007 and 2018, with an increase in overweight and obesity, and a decrease in underweight observed across different age and gender groups throughout this period. The prevalence of stunting and underweight, particularly in males in both 2007 and 2018 was substantial although lower in the later year. Adolescents expressed conflicting views of obesity, highlighting their knowledge of the cause and long-term consequences of obesity. In regard to the intervention, participants expressed support for the CHWs and the community-based intervention guided by them. The findings demonstrated the feasibility of providing the intervention to adolescents in a rural context, with modifications needed to ensure participant uptake, such as changes to the time and location. Responses from participants show how the intervention, which included dietary and quantity modifications, was acceptable to adolescents. The gathered information in this study serves as a foundation for developing a health promotion intervention tailored to the specific needs and circumstances of rural adolescents, considering both undernutrition and overweight and obesity. Conclusion This research provides valuable context-specific insights into the burden of malnutrition and perceptions of obesity among rural South African adolescents, considering the complexities of the double burden of malnutrition. The findings contribute to the development of tailored health promotion interventions that address both undernutrition and overweight/obesity in this population. Understanding the feasibility and acceptability of such interventions is vital for successful implementation and sustainability in rural communities.Item The effects of lycopene on bone, kidney and pancreatic health of growing Wistar rats fed an obesogenic diet(University of the Witwatersrand, Johannesburg, 2024) Gomotsegang, MotlhaleDietary fructose causes obesity, oxidative stress, and inflammation that compromise bone, kidney, and pancreatic health. Lycopene, a phytochemical, has antioxidant and anti- inflammatory properties. Its potential prophylactic effects on diet-induced bone, kidney and pancreatic derangements were evaluated in growing Wistar rats fed a high-fructose diet. Ninety-six 21-day old Wistar rat pups (48 females, 48 males) randomly allocated to treatment groups: I - standard rat chow (SRC) + plain drinking water (PDW) + plain gelatine cube (PGC), II - SRC + 20% fructose as drinking water (FDW) + PGC, III - SRC + FDW + 100mg/kg body mass fenofibrate per day (FF), IV - SRC + FDW + 30mg/kg body mass lycopene per day and V - SRC + FDW + 60mg/kg body mass lycopene per day and VI - SRC + FDW + 100mg/kg body mass lycopene per day were fed for 84 days. Body, kidneys, pancreata, femora and tibiae masses were determined. Kidney and pancreatic lipid content, pancreatic TBARS concentration, SOD and GPX1 activities and plasma CTX-1 and osteocalcin concentrations were measured. Femora and tibia, length, mid-shaft, sub-trochanteric medio-lateral, head and neck transverse, medio-lateral, and epicondylar diameters, maximum distal epiphyseal and proximal epiphyseal breadths and breaking strength were measured. Treatments had no effect on rats’ pancreata and males’ kidney masses (P>0.05). Fenofibrate increased the females’ kidney masses (P = 0.0056). Rats’ tibiae and females’ femora masses were similar (P>0.05). CTX-1, osteocalcin and TBARS concentrations and SOD and GPX1 activities were similar (P>0.05). Treatments did not affect the rats’ kidney and males’ pancreatic lipid contents (P>0.05). Dietary fructose increased females’ pancreatic lipid content (P = 0.0048). Lycopene prevented the fructose-induced increased pancreatic lipid content (P = 0.0048). Rats’ tibiae and femora breaking strength and femora mid-shaft diameter (MIDD) of males were similar (P>0.05). Dietary fructose reduced the females’ MIDD and males’ sub-trochanteric medio- lateral diameter (STMLD) (P>0.05). Lycopene prevented the dietary fructose-induced MIDD decrease in females (P = 0.0003). Low dose lycopene decreased (P = 0.0003) the females’ STMLD. Dietary fructose mediated sexually dimorphic effects and supplemental lycopene can protect females against fructose-induced pancreatic lipid accretion and MIDD reduction and males against STMLD reduction. In females low dose lycopene may increase the risk of femora fracturing through reduced STMLDItem A critical analysis of sugar tax in South Africa(University of the Witswatersrand, Johannesburg, 2022-03-30) Irinoye, Nakedi Jane Vanessa; Blumenthal, RoyGlobally the major leading cause of death is associated with non-communicable diseases (NCDs) and increasing in both First and Third World countries, including South Africa. The change from traditional to processed food, more energy-dense food, sugar-based drinks, more added salt, fat and sugar, are all referred to as the ‘western diet’. The transition of the food environment has been associatedwith individual influences such as behaviors, knowledge and attitudes. Globally the consumption of sugar-based drinks has increased at an alarming rate and major non-communicable diseases (NCDs) are associated with the excessive intake of sugar. One of the global health risks is obesity. In creating food environments that are healthy, international jurisdictions formulate policies and environmental interventions as an effective tool. Taxes have been employed to stabilise a downturn in the market and change the price, which have affected consumers’ purchasing decisions. In this report, sugar tax was critically analysed by evaluating the impact of the tax on the market, employment, imports and exports. Several policy design options of taxing sugar-based drinks as formulated and introduced by the World Health Organization (WHO) and The Organization for Economic Co-operation and Development (OECD) were compared. In order to determine the sustainability of the policy design option implemented by South Africa, the policy design option was compared to that implemented by other jurisdictions namely, the United States of America, Mexico and Denmark. The opponents of sugar tax challengedthe implementation of initiatives and utilization of income generated from sugar tax in South AfricaItem Obese patients reported dissatisfaction with weight, body image and interaction with clinicians at Dr Yusuf Dadoo District Hospital(2024) Kanozire, BuhendwaBackground: Obesity in South Africa has created a public health crisis that warrants a multilevel intervention. Patients’ perceptions and clinicians’ challenges hinder the management of obesity in primary care. Aim: The study aimed to assess obese patients’ dissatisfaction with weight and body image and their perspectives on interaction with clinicians in a primary care setting. Setting: Dr Yusuf Dadoo District Hospital, outpatient department. Method: Cross-sectional study of 213 adult obese patients. A semi-structured questionnaire, a body image assessment tool and patient medical records were used for data collection. Results: The study found that, contrary to popular belief, obese patients were dissatisfied with their weight (78.9%) and body image (95.3%). Many felt comfortable discussing weight reduction with clinicians, although 37.1% reported never engaging with a doctor, and 62.9% never interacted with a nurse on the subject. Only six percent reported receiving adequate information on weight reduction measures, and 19.7% were followed-up. Clinicians’ advice was mainly associated with patients’ high BMI and waist circumference. Doctors were less likely to recommend weight reduction to employed obese women, while nurses were more likely to engage Zulu-speaking patients. Patients were more likely to be followed up if there were young and excessively obese. Conclusion: The study found that most obese patients were dissatisfied with their weight and body image and perceived their interaction with clinicians inadequate Contribution: The study highlights a possible shift in obese patients’ weight and body image perception compared to previous reports. It also brings to light clinicians’ deficiencies that warrant further education on obesity management.Item Exploring the interaction of host genetics and the gut microbiome in obesity in an African population(2024) Schnell, Samantha SusanObesity is a highly prevalent health concern that is on the rise in Sub-Saharan Africa. Even though genetic variation and gut microbiota have been implicated in the development of obesity independently, the interactions between these factors have not been previously explored in a South African cohort. This study aimed to identify possible associations between host genomes, body mass index as a measure of obesity, and gut microbiota composition (in the form of V3-V4 16S rRNA sequencing) in a female African cohort. Polygenic risk scores predictive of body mass index in this cohort were generated to categorise the participants into high- and low-risk groups. Subsequently, several statistical analyses were performed comparing gut microbiota between these groups. High-risk participants with high body mass index had associations identified with increased abundances of Prevotella_9 and VadinBE97. In contrast, the low polygenic risk and low body mass index sub-group was associated with greater Bacteroides levels. This study acknowledges the plausible interactions between these factors in an African cohort.