Browsing by Author "Phaswana, Merling"

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    Association of lifestyle and sleep behaviours with blood pressure and body composition: a cross-sectional study of rural black South African women living in Tshino Nesengani
    (2019) Phaswana, Merling
    Background: The prevalence of hypertension and obesity is predicted to increase in developing countries particularly in South Africa. Recent literature indicates that rural dwelling South African black women have the higher prevalence of obesity in subSaharan Africa. The determinants of obesity and hypertension in rural black South African women are still not yet determined. Therefore the purpose of this study was to determine whether behavioural factors and covariates such as socioeconomic status (SES) were associated with body composition and blood pressure in a cohort of women living in the Tshino Nesengani rural village, Limpopo province. Methods: A cross-sectional study involving 200 African women aged ≥18 years living in the Tshino Nesengani (Mukondeleli) village was conducted. Data Collection included, anthropometry (weight, height, waist circumference, and hip circumference); systolic blood pressure and diastolic blood pressure and standardized self-reported questionnaires: Global physical activity questionnaire was used for physical activity and sitting time, Beverage intake Questionaire-15 was used to determine sugar-sweetened beverage intake, Pittsburgh sleep questionnaire index was used to determine sleeping index, and socioeconomic status was determined using SES household questionnaire. Pearson’s correlation was used to determine the correlation between body composition and blood pressure with lifestyle behaviours. Multivariable linear regression models were used to determine the association of lifestyle behaviours with body composition and blood pressure. Results: The prevalence of overweight was 25%, obesity 40%, and the prevalence of hypertension was 26%. The prevalence of cigarette smokers was 3%, snuff use was 5%, and alcohol consumption was 14.5%. Age showed a positive correlation with systolic blood pressure, diastolic blood pressure and pulse pressure. Body mass index was positively associated with waist circumference (r=0.75, p<0.0001). Total work physical activity was positively correlated with diastolic blood pressure (r=0.14, p<0.05) and total leisure moderate to vigorous physical activity, total moderate physical activity and total moderate to vigorous physical activity were positively correlated with waist circumference. In a multivariable linear regression model, body mass index was positively associated with age (β: 0.20, p<0.001), socioeconomic status (β: 0.16, p<0.02) and hypertension (β: 0.21, p<0.0001). Waist circumference was positively associated with body mass index (β: 0.67, p<0.0001), and negatively associated with completion of high school education (β:-0.14, p<0.001). Systolic blood pressure showed a positive of association with age (β: 0.40, p<0.0001) while, diastolic blood pressure was positively related to age (β: 0.21, p<0.0001) and body mass index (β: 0.24, p<0.0001), and negatively associated with hours of sleep/night (β: -0.16, p<0.02). Conclusion: The findings show that the majority of the study population were obese and hypertensive, and this confirms the urgency of these diseases to be addressed in rural-dwelling black South African women. Our findings also indicate that longer sleep may protect against hypertension. However, this finding needs to be confirmed with objective measurement of sleeping patterns.
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    Sedentary behaviour in a sample of south african office-based workers
    (University of the Witwatersrand, Johannesburg, 2024) Phaswana, Merling; Gradidge, Philippe
    Background 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 workstations