Comparative Evaluation of Blood Pressure, Central Adiposity, and Physical Activity Patterns Between Wheelchair Users and Ambulatory Adults in a Rural South African Settings: A Cross-Sectional Study Protocol

Background

Hypertension is a major modifiable driver of cardiovascular disease in low- and middle-income countries, heavily driven by central adiposity and physical inactivity. Wheelchair users represent a structurally marginalized population facing heightened exposure to prolonged sitting and altered body composition. However, context-specific epidemiological data comparing cardiovascular risk profiles by mobility status in rural South Africa remain scarce.

Objective

This study aims to compare blood pressure profiles, central adiposity (waist circumference), physical activity levels, and sedentary behavior between wheelchair users and ambulatory adults in the Thulamela Municipality, Limpopo Province, and to determine if mobility status is independently associated with hypertension.

Methods

This study utilizes an analytical, community-based cross-sectional design. A sample of N = 210 adults (n = 70 wheelchair users; n = 140 ambulatory controls) will be recruited using purposive and convenience sampling strategies within rural networks. Assessments will feature seated blood pressure measurements and seated waist circumference metrics to standardize data collection across both groups. Physical activity and sedentary durations will be quantified using the Leisure Time Physical Activity Questionnaire for Spinal Cord Injury (LTPAQ-SCI) and the International Physical Activity Questionnaire Short Form (IPAQ-SF). Outcomes will be mathematically harmonized into weekly minutes of moderate-to-vigorous physical activity (MVPA).

Analysis

Inter-group variations will be assessed using independent samples t-tests or Mann-Whitney U tests. Multivariate binary logistic regression models will isolate the independent association between mobility status and hypertension, controlling for confounding clinical and demographic factors.

Strengths and Limitations of This Study

• Strength: Standardizes both hemodynamic (blood pressure) and anthropometric (waist circumference) measurements in a seated position to eliminate positional bias between wheelchair and ambulatory cohorts.

• Strength: Harmonizes two population-validated physical activity questionnaires (LTPAQ-SCI and IPAQ-SF) into a single continuous metric (MVPA) to bridge functional measurement gaps.

• Strength: Targets an epidemiologically under-researched, structurally marginalized population in rural, resource-constrained South African settings.

• Limitation: The cross-sectional design limits the ability to establish causal relationships between mobility status, central adiposity, and the onset of hypertension.

• Limitation: Relying on self-reported questionnaires for physical activity and sedentary behavior introduces potential recall and social desirability biases compared to device-based accelerometry.