Prevalence of overweight, obesity and central adiposity among grade seven adolescents in urban Tshwane, South Africa

Abstract

Background: The global increase in overweight and obesity among adolescents is a significant public health priority, especially in low- and middle-income countries. In South Africa, urbanisation and lifestyle changes have exacerbated this challenge, but there is a lack of disaggregated data available to inform effective local responses.
Aim: To assess and describe the prevalence of overweight, obesity and central adiposity in Grade seven adolescents in urban Tshwane, South Africa, and explore its association with socioeconomic characteristics.
Setting: The study was conducted in five diverse fee-paying public primary schools in urban Tshwane, Gauteng province.
Methods: A quantitative, descriptive cross-sectional design recruited 164 adolescents aged 11–14 years. Anthropometric measures were performed according to World Health Organization (WHO) standards. These included a survey of height and weight to derive body mass index (BMI-for-age) z-scores, as well as waist circumference to height ratio (WHtR). Socioeconomic status was assessed using the validated Family Affluence Scale. Data analysis included descriptive statistics and chi-square tests to determine the association between categorical variables.
Results: The combined prevalence of overweight and obesity was 23.7%, with a greater burden among girls (36.4% of 12 year olds) compared to boys (16.7%). The risk of central adiposity (WHtR ≥ 0.5) was found in 25% of participants, with 7.3% at very high risk. Household income was significantly associated with obesity (p = 0.043), while parental education was not statistically significant.
Conclusion: The high prevalence of excess adiposity, particularly among female adolescents, indicates an emerging cardiometabolic risk profile among the group.
Contribution: This study addresses a critical gap in South African public health literature by providing locally specific, disaggregated data on the nutritional status of urban adolescents in Tshwane, a cohort that is underrepresented in contrast to conventional rural or national surveys.