4. Electronic Theses and Dissertations (ETDs) - Faculties submissions
Permanent URI for this communityhttps://hdl.handle.net/10539/37773
For queries relating to content and technical issues, please contact IR specialists via this email address : openscholarship.library@wits.ac.za, Tel: 011 717 4652 or 011 717 1954
Browse
4 results
Search Results
Item From the onset: Impact of Nutrition and Lifestyle during the Preconception period in Urban South African Young Adults(University of the Witwatersrand, Johannesburg, 2023-03) Mukoma, Gudani Goodman; Norris, Shane A.Background: In South Africa, 22% of adolescents are overweight or obese, the onset of tobacco smoking is shown to peak between the ages of 15 and 22, 1 in 3 adolescents watch more than 3 hours of television per day, and nearly half of all adults are insufficiently active. Physical inactivity, poor diet, risky alcohol use, illicit drug use are among the behavioural risk factors associated with obesity and mental health problems, all of which have morbidity and mortality implications for adult health. Risks in later life include premature death, long-term disability, childbirth complications, gestational diabetes, diabetes and cardiovascular diseases. However, there is data paucity showing the personal, social, and environmental factors that are determinants of health, especially diet, physical activity (PA), obesity, and associated NCDs in South African adolescents and young adults. Aim: To investigate the individual, household, and environmental factors that influence adolescents' dietary and physical activity habits and to identify ways in which these factors can be leveraged for interventions to better ensure the health of future generations, especially during the crucial preconception years. Methods: This thesis was purposely designed to use a sequential mixed-methods approach that integrates quantitative (Chapter 3 paper 1: cross-sectional and Chapter 6 paper 4: longitudinal) and qualitative (Chapter 4 paper 2: longitudinal and Chapter 5 paper 3: cross-sectional) analyses in order to meet the four specific objectives of my research. The methods selected for this series of investigations were primarily influenced by the substantive research questions that arose, as opposed to methodological and epistemological concerns alone. I utilized three pre-existing data sources, including the "Birth-to-Twenty Cohort," the "Determinants of Type 2 Diabetes Mellitus (T2D)" study, and the "Soweto household enumeration survey." I have gathered new prospective data that is quantitatively and qualitatively longitudinal and cross-sectional. Results: The findings of this thesis in the context of Soweto show that the relationship between dietary patterns and nutritional status (BMI) is independent of socioeconomic status (SES). Adolescents and young adults face a variety of intersecting barriers resulting from personal preferences and their living conditions, which influence their dietary and physical activity habits while occurring at the time; this is important to consider when designing interventions to promote healthy behaviour change. Unexpected stressors, such as the outbreak of the COVID-19 pandemic, contributed to exacerbating adolescents' and young adults' poor health conditions, and as a result, the prevalence of poor nutrition intake, a lack of physical activity, and mental health issues increased. Although the nutrient patterns of adolescents and adults were comparable over time, their associations with BMI were not. The associations with BMI of the "plant-driven nutrient pattern," "fat-driven nutrient pattern," and "animal-driven nutrient pattern" revealed sex differences. Conclusion: Adolescent diet and lifestyle continue to be important research areas in the intent to enhance preconception health and reducing maternal and infant mortality.Item Relationship of diet and physical activity with genetic susceptibility to obesity: a longitudinal analysis in adults in South Africa(University of the Witwatersrand, Johannesburg, 2024) Muti, Monica; Chikowore, Tinashe; Ware, LisaBackground Obesity-related disease conditions are a major public health concern in South Africa, exerting a healthcare cost of between ZAR 30 million and ZAR 36 million, the bulk of which is due to hypertension and type 2 diabetes. Moreover, evidence reveals that women in South Africa have higher BMI compared to men, yet men exhibit less insulin sensitivity and reduced beta cell function as well as stronger associations of adiposity with type 2 diabetes compared to women. The mechanisms underlying these sex differences are not known. BMI is highly polygenic in nature; however, genetic prediction of BMI has mostly been conducted using data from European ancestry populations that have poor predictive capacity in African ancestry populations. Moreover, the relationship of polygenic risks and proteomic profiles with regards to susceptibility to obesity and related cardiometabolic traits is yet to be explored in African populations. It has also been reported that using variants associated with the statistical variance of quantitative traits (vQTLs) like BMI aids in the depiction of components of BMI genetic susceptibility, which interacts with environmental factors such as diet and exercise. However, such studies are limited in continental Africans. Aim This thesis, sought to determine the interplay of diet and physical activity with BMI genetic susceptibility. The specific objectives were: 1. To determine the association of physical activity with BMI in middle-aged black South African men and women. 2. To develop a highly predictive genetic risk score for BMI and test its longitudinal predictive ability in middle-aged black South African men and women. 3. To determine gene x lifestyle (GXE) interactions that influence BMI in Black South African adult men and women. Methods Data from 11853 adult men and women in the African-Wits-INDEPTH partnership for Genomic studies (AWI-Gen) Cohort was used to fulfil objective 1. To fulfil objectives 2 and 3, data from 5921 AWI-Gen cohort participants in the three South African (SA) sites and a sub-study of AWI-Gen focusing on the factors influencing the risk of type 2 diabetes mellitus among middle-aged black South African men and women (GSK) was used. For objective 1, a sex-stratified meta-analysis of cross-sectional data from the study participants was used to assess the association of physical activity with BMI. The PRS-CSx method was used to develop a multi-ancestry PRS for BMI and evaluate its longitudinal prediction of severe obesity to meet objective 2. For objective 3, the Levene’s test, implemented in the OCSA Package, was used to determine candidate gene-interacting variants that exhibited trait variance heterogeneity in the study population. Detailed methods are in the relevant sections for each objective. Results Meeting the recommended weekly physical activity levels of at least 150 minutes was associated with a BMI that was 0.80kg/m2 lower in men (95% CI = -1.14; -0.47) and 0.68kg/m2 lower in women (95% Ci = -1.03; -0.33). Sex and site-specific differences were also observed in domains of physical activity with an inverse relationship between transport-related physical activity and BMI being observed among men in Agincourt (beta = -1.15 kg/m2, 95% CI = -2.26; -0.04) and Nanoro (beta = -0.79 kg/m2, 95%CI = -1.25; -0.33). Work related physical activity was associated with lower BMI in Navrongo men (beta = -0.76 kg/m2, 95% CI=-1.25; -0.27) and Nanoro women (beta = -0.90 kg/m2, 95%CI = -1.44; -0.36). The multi-ancestry PRS demonstrated superior predictive ability, explaining approximately 1.9% of variance in BMI compared to 0.7% and 1.2% explained by two scores developed using single ancestry methods. In addition, over a period of ten years, the multi-ancestry PRS was associated with repeated measures of BMI (β = 1.51 p = < 0.001) and there was significant longitudinal PRS * sex interaction (Pinteraction = 0.029), prompting subsequent sex-stratified analysis. In the combined analysis of men and women, being in the top 20% of the PRS distribution (top 20) was associated with three times greater hazard of severe obesity (hazard ratio = 2.98, 95% CI = 1.75 - 5.07, p = 5.33e-05) compared to being in the bottom 20% of the PRS distribution (bottom 20). This observation was shown to be driven by women, where being a woman in the top 20 was associated with 3.5 greater hazard of severe obesity (hazard ratio 3.48, 95% CI = 1.96 – 6.16, p = 1.94e-05) compared to being in the bottom 20 while the associations were not significant in men (hazard ratio = 1.13, 95% CI = 0.24 – 5.37, p = 0.878). Comparison of the associations of dysglycaemia with PRS, BMI and the proteomic score revealed no apparent sex differences in the association between BMI PRS and dysglycaemia for most of the glycaemic markers except for Matsuda Index though men exhibited lower insulin sensitivity compared to women. The proteomic score predicted higher insulin resistance in women than in men. Gene x lifestyle interaction analysis revealed novel interactions between three genetic variants with diet and lifestyle factors. The effect of the rs557505940 variant on BMI was accentuated by higher fruit intake (betainteraction = 0.03, Pinteraction = 0.04) in the combined analysis of men and women while higher SES, carbohydrate intake and self- reported physical activity attenuated the effect of rs527747185 (betainteraction = -0.349, Pinteraction = 0.037), rs3016751 (betainteraction = -0.056, Pinteraction = 0.035) and rs188275749 (betainteraction = -0.048, Pinteraction = 0.0001) respectively on BMI in men. Conclusions Sex and geographical differences exist in associations between domains of physical activity and BMI. In addition, genetic risk better predicts incident severe obesity in women than in men while proteomic profiles have a weak correlation with PRS and show heterogenous associations with dysglycaemia, fat distribution, nutrient patterns and physical activity between men and women. Novel GXE interactions were also observed. These results underscore the need for further inquiry into the sex differences in genetic risk and environmental factors associated with BMI. Furthermore, a precision approach to obesity prevention and control, paying attention to the sex differences and contextual factors may be more efficient.Item Sedentary behaviour in a sample of south african office-based workers(University of the Witwatersrand, Johannesburg, 2024) Phaswana, Merling; Gradidge, PhilippeBackground Sedentary behaviour is associated with cardiometabolic diseases amongst office- bound workers, primarily through extended sitting and engaging in low-energy- demanding activities during work hours. Similar to developed countries, South African workplaces are experiencing an increasing prevalence of obesity and related cardiovascular diseases, with sedentary behaviour and physical inactivity being the main contributors. However, there is limited data on the effectiveness of sedentary behaviour strategies in improving South African office-based workers' cardiometabolic risk markers. Objectives This study aims to assess the effectiveness of the height-adjustable sit-to-stand work on cardiovascular parameters in a cohort of office-based workers and to explore the perceptions of these workers about the feasibility and suitability of this intervention to reduce occupational sitting time. Methods A mixed-methods study design was used on office workers from the University of the Witwatersrand and a credit bureau company in South Africa. The qualitative papers used in-depth semi-structured interviews to explore office-based workers' perceptions and experiences using sit-to-stand workstations. The interview audio was recorded audio using Microsoft Teams (version 11, Microsoft Way, United States) and Phillips (DVT4010 Voice Tracer, Vienna, Austria). All transcripts were checked against the recordings to verify accuracy and credibility, and grammatical editing was adopted where necessary. For quantitative measures, participants were randomised into an intervention or control group to collect measures at baseline and 12 weeks in a cohort of South African desk-based workers. These biomarkers include anthropometry, sedentary behaviour and physical activity, sleep duration, blood pressure, glucose, glycated haemoglobin (HbA1c) and lipid profile. The cross- sectional paper quantified sedentary behaviour, overall physical activity, and the association with select cardiometabolic risk factors. The randomised control trial evaluated the short-term effects of height-adjustable sit-to-stand workstations on cardiometabolic risk markers. Descriptive and inferential statistics were used to describe and compare baseline and follow-up changes in the intervention. Results The height-adjustable sit-to-stand workstation was deemed feasible and well-accepted by our participants. Participants expressed that it motivated them to stand up and work and effectively alleviated discomfort associated with prolonged sitting. Most (68.0%) of the study participants were women, with a mean age of 40.2 ± 9.3 years. Our participants spend an average of 8 to 10 hours in sedentary behaviour. Both systolic (β: -0.234, p = 0.037 mmHg) and diastolic blood pressure (β: -0.250, p <0.001 mmHg) were inversely associated with accelerometery-measured light physical activity. However, there was no relationship between accelerometery- measured sedentary behaviour and cardiometabolic risk factors after analysis. The 12-week randomised control trial showed small improvements with blood pressure - 0.26 (d =1.10 mmHg) and Light physical activity -0.26 (d=3.57 min/day). We observed trivial effects, with most of our cardiometabolic outcomes including body mass index (BMI) -0.11 (d=1.07 kg.m2). Most participants withdrew early from workplace intervention due to the design and functionality of the height-adjustable sit-to-stand workstation. Conclusions This study adds to the limited evidence on environmental workstation modifications for reducing sedentary behaviour. Our findings show that South African office workers spend a substantial amount of time sitting during work hours and support the need for public health workplace interventions to mitigate the potential health risks associated with such sedentary behaviour. This study confirms that short-term height-adjustable sit-stand interventions effectively reduce workplace sitting time and promise to improve cardiometabolic health outcomes, suggesting that clinically significant effects might be noticed in long-term interventions. Therefore, future studies should consider individual preferences, workstation design, functionality, education, and motivation to ensure successful implementation, utilization, and compliance with sit-to-stand workstationsItem The effect of smartwatches on patient-centered healthcare(University of the Witwatersrand, Johannesburg, 2022) Ndhlovu, Patson; Ndayizigamiye, PatrickPatient-centered healthcare lies at the core of health and social services, where individuals are recognized and encouraged to take an active role in their own care. The literature suggests that technological advancements are contributing to achieving patient-centred care. As technology is advancing, it is important to keep abreast of how emerging technologies are affecting patient-centred healthcare. Thus, the purpose of this study was to investigate the effects of smartwatches on patient-centred healthcare. To achieve this, this study assessed the effect of features of smartwatches on the Picker's 8 principles of patient-centred healthcare. The sample for this study was 141 participants who use smartwatches. These participants were all part of a running club based in Gauteng province of South Africa. The findings revealed that the activity tracking feature of a smartwatch has a moderate impact on emotional comfort and coordination and integration of care. Similarly, the vital signs monitoring feature has a moderate effect on the continuity and transition of care, while the data management feature demonstrated a moderate effect on the coordination and integration of care. Moreover, the activity tracking feature of a smartwatch has the strongest effect on the coordination and integration of care, while vital signs monitoring has the strongest effect on the continuity and transition of care. The data management feature, on the other hand, has the strongest effect on the coordination and integration of care. Findings from this study, albeit their limitations, can assist healthcare providers to make informed decisions on which features of smartwatches they should focus on when promoting the use of wearables to provide patient-centred car