Body composition and physical activity as mediators in the relationship between socioeconomic status and blood pressure in young South African women: a structural equation model analysis.
Micklesfield, Lisa K
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Munthali, R. J., Manyema, M., Said-Mohamed, R., Kagura, J., Tollman, S., Kahn, K., Gómez-Olivé, F. X., et al. (2018). Body composition and physical activity as mediators in the relationship between socioeconomic status and blood pressure in young South African women: a structural equation model analysis.. BMJ open, 8 (12), e023404. https://doi.org/10.1136/bmjopen-2018-023404
OBJECTIVES: Varying hypertension prevalence across different socioeconomic strata within a population has been well reported. However, the causal factors and pathways across different settings are less clear, especially in sub-Saharan Africa. Therefore, this study aimed to compare blood pressure (BP) levels and investigate the extent to which socioeconomic status (SES) is associated with BP, in rural and urban South Africa women. SETTING: Rural and urban South Africa. DESIGN: Cross-sectional. PARTICIPANTS: Cross-sectional data on SES, total moderate and vigorous physical activity (MVPA), anthropometric and BP were collected on rural (n=509) and urban (n=510) young black women (18-23 years age). Pregnant and mentally or physically disabled women were excluded from the study. RESULTS: The prevalence of combined overweight and obesity (46.5% vs 38.8%) and elevated BP (27.0% vs 9.3%) was higher in urban than rural women, respectively. Results from the structural equation modelling showed significant direct positive effects of body mass index (BMI) on systolic BP (SBP) in rural, urban and pooled datasets. Negative direct effects of SES on SBP and positive total effects of SES on SBP were observed in the rural and pooled datasets, respectively. In rural young women, SES had direct positive effects on BMI and was negatively associated with MVPA in urban and pooled analyses. BMI mediated the positive total effects association between SES and SBP in pooled analyses (ß 0.46; 95% CI 0.15 to 0.76). CONCLUSIONS: Though South Africa is undergoing nutritional and epidemiological transitions, the prevalence of elevated BP still varies between rural and urban young women. The association between SES and SBP varies considerably in economically diverse populations with BMI being the most significant mediator. There is a need to tailor prevention strategies to take into account optimising BMI when designing strategies to reduce future risk of hypertension in young women.
Humans, Hypertension, Exercise, Risk Factors, Cross-Sectional Studies, Body Composition, Blood Pressure, Social Class, Adolescent, Rural Population, Urban Population, South Africa, Female, Young Adult, Latent Class Analysis
SAN is supported by the UK MRC DfID African Research Leader Scheme and by the DST-NRF Centre of Excellence in Human Development at the University of the Witwatersrand, Johannesburg. Birth to Twenty data collection was supported by the Wellcome Trust under grant (092097/Z/10/Z). The MRC/Wits- Agincourt Unit is supported by the South African Medical Research Council, and the Wellcome Trust under grants (058893/Z/99/A, 069683/Z/02/Z, 085477/Z/08/Z, 085477/B/08/Z).
Wellcome Trust (092097/Z/10/Z)
External DOI: https://doi.org/10.1136/bmjopen-2018-023404
This record's URL: https://www.repository.cam.ac.uk/handle/1810/301133
Attribution 4.0 International
Licence URL: https://creativecommons.org/licenses/by/4.0/