The effect of urbanisation on the relationship between physical activity and obesity in 10-15 year old males in the North-West province of South Africa: Thusa Bana study

Abstract

The purpose of this study was firstly to investigate the relationship between physical activity and measures of obesity in 10-15 year old males in the North-West Province of South Africa. Secondly, the study aimed at determining the influence of age on the possible relationship between physical activity and obesity and thirdly, at determining the influence of urbanisation on the possible relationship between physical activity and obesity. A one-time cross sectional experimental design was used for this study. A total of 606, 10-15 year old males were recruited from 44 randomly selected schools in the North-West Province, which formed part of the THUSA BANA study during 2000 and 2001. Demographic data and physical activity participation were obtained through standardized questionnaires. Anthropometric measurements selected, were primarily those described in Norton and Olds (1996). Data analysis was performed using Statistica 2000 for Windows 1998. A one-way (ANOVA) and two-way analysis of variances together with Tukey post hoc HSD tests were used to indicate the differences between variables. The level of significance was set at p<0.05. Physical activity was not significantly associated with percentage body fat, body mass index or the sum of triceps and subscapular skinfolds in analysis of variances (ANOVA). Although there were no statistically significant differences between physical activity and the measures of obesity, the measures of obesity increased with a decrease in physical activity. In the application of the two-way analysis of variance, to determine the influence of age on the relationship between physical activity and obesity, some significant relationships were shown. The measures of obesity increased with an increase in age. There were also significant associations found in the application of the two-way analysis of variance, which determined the influence of urbanisation on the relationship between physical activity and obesity. The rural subjects had lower values of the indicators of obesity than the semi-urban and urban subjects, independent of their level of physical activity. This could indicate that socio-economic status and its influence on nutritional status, play an important role in the prevalence of obesity.


Keywords: Anthropometry, Age, Obesity, Physical activity, South Africa


South African Journal for Research in Sport, Physical Education and Recreation Vol.25(2) 2003: 77-92