Body composition profiles of underweight and obese grade one learners in the North West Province of South Africa : NW–CHILD study
Body composition profiles including stunting, wasting and underweight, overweight and obesity, can all affect the health, motor development and academic achievements of children. South Africa (SA), a developing, middle-income country, with large socio-economic inequalities, is one of the most complex nations with regard to race and ethnicity. It therefor results in different body composition profiles of children and adolescents, where undernutrition and obesity can occur among children and adolescents in the same socio-geographic population in disadvantaged communities, as well as in the same household. The aim of this study was firstly, to determine the incidence of overweight and obesity among Grade 1-learners in the North West Province of SA and to determine whether this incidence is related to gender, race and the socio-economic circumstances in which these learners live. Secondly, the study aimed to determine the incidence of stunting, wasting and underweight among this group of Grade 1-learners and to determine whether these incidences are related to gender, race and the socio-economic circumstances in which these learners live. The anthropometric measurements that were used in the study were height (cm), body mass (kg), 3 skinfolds [(sub-scapular, triceps and medial calf)] (mm) and waist circumference (cm). These measurements were taken by trained researchers according to the guidelines International Society for the Advancement of Kinanthropometry (ISAK). Body mass index (BMI) [(body mass (kg)/height (m)2)] was calculated and international age-specific cut-off points for BMI was used to determine whether a learner was overweight or obese. Z-scores of less than -2 standard deviation (SD) for height-for-age and weight-for-age were calculated to determine the prevalence of stunting and underweight, while the Z-scores for wasting was determined using BMI-for-age, under the 5th percentile from an international reference population. The Statistica-computer programme (Statsoft, 2011) and AntroPlus software (version 1.0.2) in SAS (Statistical Analysis System) were used to analyse the data. Data were descriptively analysed by using percentages, means (), minimum and maximum values and standard deviations (SD). Two-way frequency tables were used to analyse the incidence for overweight, obesity, stunting, wasting and underweight. Pearson Chi Square analysis p≤0,05 was used to determine statistical significance of differences in stunting, wasting and underweight between school types, race and genders. Practical significance of differences was determined using effect sizes (d≥0,1 which indicates a small effect, d≥0,3 indicating a medium effect and d≥0,5 indicating a large effect). Tukey’s Post Hoc tests were used to determine the significance of differences between the groups and genders. The results revealed an incidence of 11,6% of overweight and obesity in the group (N=816) of Grade 1-learners. Overweight in the group was 7,8% and overweight was more prevalent in 7 year old learners with 10,5%, compared to 6 year old learners with 6,3%. Obesity (3,8%) showed a lower incidence compared to overweight, were 2,5% learners at 6 years and 0,7% learners at 7 years were obese. The boys showed the highest prevalence for severe obesity at 6 and 7 years (2,4%). White learners showed the highest prevalence for overweight, obesity and severe obesity at 6 and 7 years. The group of Grade 1-learners furthermore showed lower percentages of stunting (4,3%), wasting (7,4%) and underweight (4,3%) compared to overweight and obesity incidences. A higher prevalence of wasting and underweight were found among the boys (8,4%; 6,0%) compared to the girls (6,3%; 2,5%), although the difference was only significant for underweight (p=0,02), while stunting was similar among girls (4,5%) and boys (4,1%; p>0,05). Black learners showed the highest incidence for underweight (5,5%; p<0,01), while small percentages of underweight were found in the white learners. Only the black learners showed stunting (p<0,01), while wasting occurred in black (n=39) and white (n=15) learners. Quintile 1-3 schools had the highest prevalence of underweight (5,1% – 8,2%) and stunting (3,9% – 10,7%), which was significantly higher than in Quintile 4 and 5 schools (p<0,01), and agreed with higher prevalences found in rural areas in other South African studies. Knowledge about the body composition profiles of young school beginners is important since extremes such as obesity, stunting and wasting play an important role in the further development and health of children. The results of this study make a valuable contribution to knowledge that can be used in this regard for preventative purposes.
- Health Sciences