Underweight, overweight and obesity among South African adolescents: results of the 2002 National Youth Risk Behaviour Survey.

OBJECTIVE: The present paper reports the prevalence of underweight, overweight and obesity by gender, ethnicity and grade, among participants in a 2002 national survey among South African school-going youth that included height and weight measurements. DESIGN: A stratified two-stage sample was used. Nationally representative rates of underweight, overweight and obesity were calculated using weighted survey data and compared using chi2 analysis. SETTING: In all, 9224 grade 8 to grade 11 students, present at school in selected classes within selected South African government-funded schools in all nine provinces, participated in this study. Most of the students were between 13 and 19 years of age. RESULTS: Higher rates of underweight were observed for males than females as well as for black and 'coloured' than white students. Within each gender group, black and 'coloured' students had significantly higher rates of underweight than their white counterparts. Higher percentages of females than males were overweight and obese, overall and among black students. Furthermore, white male students had significantly higher rates of overweight than their black and 'coloured' counterparts. Among females, black and white students had significantly higher rates than 'coloured' students. Students in higher grades showed significantly lower rates of underweight and higher rates of overweight. DISCUSSION: These data confirm that South Africa, a developing nation in socio-economic transition, is experiencing both undernutrition and overnutrition. However, these problems are disproportionately distributed by gender, socio-economics and ethnicity. Continued surveillance of nutritional status may be one important component of a national strategy to prevent and control malnutrition.

Sex differences in under and over nutrition among school-going Black teenagers in South Africa: an uneven nutrition trajectory.

OBJECTIVES: To investigate the nutritional status of Black South African teenagers by sex and compare it with nutritional profiles of teenagers from other countries. METHODS: The first South African Youth Risk Behaviour Survey (2002) was adapted to include anthropometric data and this paper reports on the prevalence of under and over nutrition among 5322 Black teenagers, aged 13.0-17.9 years, grades 8-11. Prevalence of over nutrition in this study was compared with other countries using a World Bank country economic classification. RESULTS: Significant sex differences were observed for under and over nutrition. Boys (18.4%) had a higher prevalence of underweight than girls (2.6%) (P < 0.005), who were more at risk of overweight than boys (20.9%vs. 4.2%) (P < 0.005). Boys (21.9%) were more stunted than girls (9.4%) (P < 0.05), but stunted girls were at greater risk of overweight than boys across all levels of stunting. The prevalence of overweight among boys (4.2%) was lower than in other countries while for girls (20.9%) was similar to several upper middle and high income countries. CONCLUSION: Gender sensitive strategies are required to address both under and over nutrition among South African teenagers to reduce stunting and future chronic disease epidemics in adulthood. This paper suggests that Black South African teenagers are experiencing an uneven nutritional transition across sex, from under nutrition to over nutrition.