Ethnicity and prevalence of obesity and high blood pressure among 10 - 15 year-old South African children

Abstract

Population studies have repeatedly found that black populations have a higher prevalence of high blood pressure in comparison with other ethnic groups. Blacks, coloured and Indians in South Africa are currently in a process of urbanization, which may lead to chronic diseases of lifestyle like hypertension. The purpose of this study was to determine the prevalence of obesity and high blood pressure in 10 – 15 year old Black, Indian, White and Coloured children in North West Province of South Africa. A cross-sectional experimental design was used for this study. A total of 1242 children, made up of 604 boys and 638 girls from different ethnical backgrounds 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. Resting blood pressure was recorded with the Finapress in a non-invasive way. Anthropometric measurements were primarily those described by Norton and Olds (1996). Percentage body fat was classified into three categories namely, high, normal and low, according to the classification of Lohman (1992). The highest prevalence of obesity in the male group was found in the white population (21.6%), while the highest prevalence of obesity in the female group was found in the Indian population (25.6%). Significant differences (p<0.05) regarding obesity were found between the different ethnical groups. The highest prevalence of high systolic and diastolic blood pressure in the male group was found in the White population. The highest prevalence of high systolic blood pressure in the female group was found in the white population (24.4%), while the highest prevalence of high diastolic blood pressure was found in the black population (24.1%). Statistically significant differences regarding systolic and diastolic blood pressure were found in both males and females, between the different ethnic groups. The study concludes that ethnicity has an influence on the prevalence of obesity and high blood pressure among 10–15 year old children in the North West Province of South Africa. This influence could also be attributed to the different environmental factors that the different ethnic groups are exposed to. Consequently, understanding those environmental factors like socio-economic status, dietary intake and physical inactivity that contribute to population or ethnic differences in obesity and blood pressure levels over time is imperative.

Key words: Blood pressure, Obesity, Ethnicity, Children, Urbanization.

AJPHERD Vol.11(2) 2005: 121-131