Student Number : 0310100X - MSc dissertation - Faculty of Health Sciences / Eating patterns change over time. Studies have been conducted in industrialized countries stating that it is important to study the longitudinal development of dietary intake itself and to determine the stability of this intake, but monitoring longitudinal dietary habits of the same children over a period of time, in particular with regard to individual food items, is severely limited in developing countries such as South Africa. South Africa, a country with diverse cultures, is undergoing massive socio-economic and political changes, and an increasing social integration following the abolishment of the previous apartheid legislation. Obviously diet too must have been affected. The country is in a state of nutritional transition, and if the nutritional status of South African children is to improve in the 21st century, basic knowledge is required of the actual food items the children have been and are consuming, and the change in consumption of these individual food items during this transition. The Birth-to-Twenty (Bt-20) study is the continuation of Birth-to-Ten (BTT) study, which started in 1990 and plans to continue to 2010. It is the largest running cohort study on children’s development in Africa and also the first and only longitudinal study on the nutrient and individual food item intake of South African children, living in the Johannesburg/Soweto area of the Gauteng Province. This research will thus provide valuable, unique information on the individual food items consumed and change in consumption of these foods by South African children from the Bt20 study over an eight-year period (1995–2003). The overall objective of this study was to determine the variety and change in consumption of individual food items consumed by a true longitudinal group of urban black South African children from the Bt20 study in 1995; ’97, ’99, 2000 and 2003 when they were 5, 7, 9, 10 and 13 years of age, respectively. with the following sub-objectives: • To determine the number of times each food item was recorded by the longitudinal group of children. • To determine the percentage of children consuming the individual food items. • To determine the mean weekly frequency of consumption of the individual food items for all the children, as well as for only those children consuming the items. The study sample size comprised a true longitudinal group of urban black South African children (n = 143), from the Bt20 study that had nutrition information at all 5 interceptions (1995, 1997, 1999, 2000 and 2003). Data were collected at each interception using the same semi-quantitative food frequency questionnaire. Parents/guardians or the children themselves were asked by trained multi-lingual interviewers to indicate how frequently the listed food items were consumed. The food items were coded onto computer coding sheets using the South African Medical Research Council’s Food Composition Tables and Codes. Recorded or standard portions sizes were used based on the use of the National Research Institute for Nutritional Diseases(NRIND) Food Quantities Manual. The coded data were put on disk by a data capturing company and SAS was used for statistical analysis. Specific computer programmes were written to systematically re-arrange and merge the data by subject ID number. The final longitudinal sample with nutrition information at 5 interceptions was extracted by ID number as each child kept the same ID number for all interceptions. Frequencies were calculated for: 1. The number of times each food item was recorded per week, firstly for all five interceptions combined and secondly for each interception separately. The total number times each food item was recorded for all five interceptions combined was divided by the total number of times all food items at all five interceptions combined (23840) were recorded and expressed as a percentage. The total number of times each food item was recorded at each interception separately was divided by the total number of children in the group [n=143] and expressed as a percentage. 2. The total weekly frequency of consumption for each food item. The mean weekly frequency of consumption for each food item was calculated for all the children in the group [n=143] for each interception separately (total weekly frequency of consumption of each food item/total number of children [n=143] and then only for those in the group consuming the food items (total weekly frequency of consumption of each food item/number of times each food item was recorded for each interception. The food items were ranked in descending order according to: • their percentage contribution of the total number of times all food items at all five interceptions combined were recorded • the average number of times recorded for all five interceptions combined • the mean weekly frequency of consumption for all five interceptions combined. The ranked food items were then arranged within the 8 food groups listed in the questionnaire (chapters 3, 4, 5). Forty-one food items made up 1% or more of the total number of times all food items were recorded for all five interceptions combined. This was used as a cut-off point as all the other food items were recorded too infrequently to include. For this reason only these forty-one items will be discussed in chapter 3, 4 and 5 of this thesis. A total of 546 different food items were recorded 23840 times between 1995-2003. The highest number of food items recorded was in 1999 (124) and 2003 (123) both almost 23% of the total number of food items recorded when the children were nine and thirteen years old, respectively. Of this, 41 items contributed 1% or more of the total number of recordings. There was a decrease in the number of recordings from the grain and cereal group, fruits and vegetables and milk and milk products. However, among the meat and meat substitutes, the number of recordings for chicken and cheese increased over this time as did the number of recordings for margarine and ice-cream among the fats and oils. Among the miscellaneous group sugar, sweets, tea and carbonated beverages remained fairly stable over the 5 interceptions, but there was an increase in the number of recordings for crisps and chocolates from 2000 to 2003. Ninety percent or more of the children consumed rice, stiff maize-meal porridge, chicken, sugar, sweets and tea over the five interceptions. Fourteen food items were consumed by 75% or more of the children and 33% of these 41 items were consumed by 50% or more. All the top 41 food items were consumed by more than 33% of the children. Among grain/cereal group/breakfast cereal/porridges and other starches, the most frequently consumed food items were brown bread, stiff and soft maize-meal porridge, all being consumed between 4-6x/week for all the children as well as for only those consuming these items. Peanut butter, eggs and chicken were the most frequently consumed items among the meat and meat substitutes, 3-5x/week for all the children and for only children consuming these items. In the group of fruits and vegetables, fruit juice and mashed potato were consumed most frequently, but not everyday of the week either for all the children or for those consuming these items. Within fats and oils food group, cooking oil and butter were consumed most frequently (3-4x/week) for all the children and 5x/week for only those children who consumed these items. Full cream milk was the most frequently consumed food item (5-6x/week) among the group of milk and milk products for all the children as well as for only those consuming this item. Among the miscellaneous food items sugar (5-6x/week), sweets and tea (4-5x/week) were the most frequently consumed for all the children and between 5-7x/week for only those consuming these items. The dietary patterns of this longitudinal group of urban black South African children was far from the recommended South African Food-Based Dietary Guidelines (FBDGs), which was developed with the aim of making evidence-based nutrition and lifestyle messages to the public accessible, understandable, generalizable, acceptable in a cross-cultural context and feasible. Thus, this study has provided useful insights to guide the governmental parastatals, nutrition scientists and other interested cooperate bodies in promoting successful nutrition intervention strategies that will lead to healthy dietary habits among children and adolescents.

While osteoporosis is a major public health concern in the developed world, little research regarding factors influencing bone mineral accrual in children has been conducted in developing countries. South Africa is of particular interest since the incidence of hip fractures in South African Blacks has been reported to be amongst the lowest in the world (32; 253). In this thesis, the association of lifestyle factors; in particular physical activity (PA), socio economic status (SES) and dietary calcium intakes on the growing skeleton of Black and White South African children is investigated. After using accelerometry to validate a physical activity questionnaire (PAQ), in a convenience sample of South African Black, White, male and female children (n=30), fitness levels were assessed in a larger group (n=69) of similarly aged children, stratified by race and gender. Fittest subjects had significantly greater physical activity scores (p=0.022) as reported on the PAQ, lower body mass index’s (BMI) (p=0.001) and least percentage body fat (p=0.001) (as assessed using Dual Energy X-ray Absorptiometry (DXA), than least fit subjects. White males who reported to be significantly more active than all other groups on the PAQ were significantly fitter (p<0.001) than White females and Black males and females. The next study sought to determine whether differences observed in physical activity levels between groups showed an association with bone mineral content (BMC), density (BMD) and area (BA) (as assessed using DXA). PA was analyzed in terms of a metabolic (METPA; weighted metabolic score of intensity, frequency, and duration) and a mechanical (MECHPA;sum of all ground reaction forces multiplied by duration) component for 386 children aged 9.5 (0.04) years recruited from a longitudinal birth cohort study. White children expended a significantly greater energy score (METPA of 21.7 (2.9)) than Black children (METPA of 9.5 (0.5), p< 0.001). When children were divided into quartiles according to the amount and intensity of sport played, the most active White children had significantly higher (p<0.05) whole body BMD and higher hip and spine BMC and BMD after adjustment for body size than less active children. White children in the highest MECHPA quartile also showed significantly higher (p<0.05) whole body, hip, and spine BMC and BMD after adjustment for body size than those children in the lowest quartile. No association between PA and bone mass of Black children was found. No significant differences between METPA and MECHPA quartiles and BA were observed for any group. Given the disparate backgrounds from which many South African children come, the next study sought to determine whether differences in socio-economic status between Black and White South African children influence PA patterns. This study explored the relationship between socio-economic status, PA anthropometric and body composition (via DXA) variables in 381 children aged (9.5 (0.04) years) recruited from a longitudinal birth cohort study . Children falling into the highest socio-economic status quartile had mothers with the highest educational levels, generally came from dual parent homes, were most physically active, watched less television, weighed more and had greater lean tissue than children in lower socio-economic quartiles (p<0.001). Significantly greater levels of lean mass (p<0.001) with increased activity level were observed after controlling for television watching time and fat mass. There were high levels of low physical activity and high television watching time among lower socio-economic status groups. White children were found to be more active than Black children, more likely to be offered physical education and to participate in physical education classes at school and watched less television than Black children. The final study sought to investigate the association between habitual PA patterns and dietary calcium intakes with bone mass acquisition over a one year period in 321 pre-pubertal South African children recruited from a longitudinal birth cohort study. Data were analyzed by regressing change in BMC and BA from age nine to ten years, against BA (for BMC), height and body weight. The residuals were saved and called residualized BMCGAIN and BAGAIN. Residualized values provide a good indication of weight, height and BA-matched accumulation rates. White children had significantly higher PA levels and calcium intakes than Black children. Most active White males had significantly higher residualized BMCGAIN and BAGAIN at the whole body, hip and spine but not at the radius, than those who were less active. Most active White females had significantly higher residualized BAGAIN at all sites except the radius than less-active girls. No such effects were seen in Black children. There was no interactive effect on residualized BMCGAIN or BAGAIN for calcium intake and PA in boys or Black girls, but an interactive and possible synergistic effect of calcium and physical activity was observed at the spine, radius and hip in White girls. In this population, PA has an osteogenic association with White children, but not Black children, which may be explained by the lower levels of PA in the Black children. Despite this, Black children had significantly greater bone mass at the hip and spine (girls only) (p< 0.001) even after adjustment for body size.In conclusion, differences between White and Black children’s PA levels were observed, with White children reporting higher PA levels and exhibiting higher fitness levels than Black children. Physical fitness correlated well with self reported physical activity levels on the PAQ and objectively measured body composition. Socio-economic status differences between White and Black children are highly related to differences in physical activity patterns and body composition profiles. Bone mass and area gain is accentuated in pre- and early-pubertal children with highest levels of habitual physical activity. Limited evidence of an effect of dietary calcium intakes on bone mass in boys and Black girls was found. The role of exercise in increasing bone mass may become increasingly critical as a protective mechanism against osteoporosis in both South African race groups, especially because the genetic benefit exhibited by Black children to higher bone mass may be weakened with time, as environmental influences become stronger.

A lower resting energy expenditure (REE) has been suggested to partially explain the disproportionate prevalence of overweight/obesity among black African women, yet no studies have investigated the REE of South African (SA) children. Similarly, physical activity (PA) as a modifiable factor related to childhood energy expenditure is under-researched in the local context. The study determined the relationship between sex and population group (determinant factors), on the one hand, and REE and PA (outcomes) of 6–9-year-old SA children attending two primary schools in the City of Tshwane metropolitan area, on the other, taking phenotypic characteristics as confounders (mediating factors) and the study context into account. In a cross-sectional study with quota sampling, the REE of 6–9-year-old children attending two urban schools in SA was measured with indirect calorimetry (IC), and PA with a pedometer. Multifrequency bioelectrical impedance analysis was used to assess body composition (BC) (fat-free mass [FFM], FFM index, fat mass [FM] and FM index). Multivariate regression was used to calculate REE and PA adjusted for phenotypic confounders (z-scores of weight-for-age, height-for-age and body mass index-for-age, and BC). Sex and population differences in REE and PA (measured and adjusted) were determined with two-way ANOVA. Ninety-four healthy children (59.6% girls; 52.1% black African) with similar socio-economic status and access to PA participated in the study. Despite variations in BC, sex differences in REE were not significant (41 kcal/day ≈ 172 kJ/day; P = 0.375). The REE in black African participants was significantly lower than in their white counterparts (146 kcal/day ≈ 613 kJ/day; P = 0.002). When adjusting for BC, population differences in REE declined, especially after adjustment for FFM (91 kcal/day ≈ 382 kJ/day; P = 0.039), but remained clinically significant. Average steps/day in girls (10212 [9519;10906]) was lower than in boys (11433 [10588;12277]) (P = 0.029), and lower in black African (9280 [8538;10022]) than in white (12258 [11483;13033]) (P < 0.001) participants. No significant relationship (r = 0.05; P = 0.651) was observed between REE and PA. Within the context of a similar SES and PA environment, the REE and PA of black African children was lower than white. Differences in REE between sexes were not significant, but girls had a lower PA than boys. / Thesis (PhD (Dietetics))--University of Pretoria, 2020. / South African Sugar Association project No. 260 / Human Nutrition / PhD (Dietetics) / Unrestricted

It is well documented that behavioural and biological risk factors for Chronic Diseases of Lifestyle (CDL) such as overweight and high blood pressure persist from childhood into adulthood. CDL is considered to be a group of diseases that shares similar risk factors as a result of exposure over many decades to physical inactivity, unhealthy diets, smoking, lack of regular exercise, and possibly stress. This study assessed health-related physical fitness and risk factors associated with obesity among 1361 (boys: n=678; girls: n=683) primary school children aged 9-12 years in the Limpopo (LP) and Mpumalanga (MP) Provinces, South Africa. Anthropometric and physical fitness measurements were taken using the protocol of the International Society for the Advancement of Kinanthropometry (ISAK) (Marfell-Jones, et al., 2006) and EUROFIT (1988) test batteries. Body composition measures included body mass index (BMI) (weight/height2), percentage body fat (%BF) and waist-to-hip ratio, respectively. BMI for age and gender was used to classify the children as underweight, overweight or obese (Cole et al., 2007), whilst %BF calculated from the sum of two skinfolds (triceps and subscapular) using the equation of Slaughter et al. (1988) indicated adiposity. The International Physical Activity Questionnaire (IPAQ) was used to categorise the children’s physical activity (PA) level as follows: Low (METs scores of less than 500); Moderate (METs scores from 500 to 1499) or High (METs >1500). In general, 75% of the children were underweight/stunted and 1.6% overweight. Frequencies of underweight, normal weight and overweight were 77%, 22.4% and 0.2% in MP and 72%, 24% and 3% in LP province. Boys were generally taller and heavier than girls. At age 10 the MP boys performed significantly (p=0.05) better in sit-ups (SUP: 20.5 ±5.4) than the LP boys (18.6±6.56). However, the LP boys performed significantly better than the MP boys in sit-and-reach (SAR) at ages 10 and 11. The MP boys performed significantly (p=0.00) better in SBJ (121.6±9.1cm) compared to the Limpopo (118.4±11.00cm) boys at age 9. Generally, LP boys were significantly (p=0.00) better than the MP boys across all ages. The PA results showed that 27.7% (377), 58.5% (796) and 13.8% (188) of the children participate in low, moderate and high PA, respectively. Children in the MP province had higher PA (28.6%) in comparison to the low PA participation in LP children (26.7%). Furthermore, 59.7% of MP children compared to the LP children (57.3%) participate in moderate PA. A higher PA participation rate (15.8%) was found among the LP than MP children (11.6%). The girls had non-significantly higher BP values (systolic: 112.94±11.28mmHg; diastolic: (79.40±12.80mmHg) than boys (systolic: 110.71±14.95mmHg; diastolic: (75.53±12.53mmHg) who had higher PA levels (METs =1286.72±317.47) than girls (METs =397.28±30.14) (p<0.01). A total of 81% (n=1089) and 19% (n=253) of the combined samples had normal BP and prehypertension, respectively. When controlled for provinces, gender and age, results indicated that BMI was negatively associated with systolic BP (SBP) (-0.54) (p<0.01), but positively correlated with %BF (0.133) (p<0.01), whilst SBP related positively with %BF (0.125) (p<0.01). The children’s PA level correlated positively with BMI (0.86) (p<0.01) but negatively with %BF (-0.67); weight circumference (WC) (-0.41); SUP (sit-up) (-0.22); and predicted 2max • VO (-0.17) (p<0.05). The high percentage of underweight and pre-hypertensive children in the study warrants an urgent need to periodically evaluate PA levels among South African children and design appropriate intervention programmes to alleviate concerns over body weight disorders and low PA levels in children, thus optimising health outcomes. / PhD (Human Movement Science), North-West University, Potchefstroom Campus, 2015

It is well documented that behavioural and biological risk factors for Chronic Diseases of Lifestyle (CDL) such as overweight and high blood pressure persist from childhood into adulthood. CDL is considered to be a group of diseases that shares similar risk factors as a result of exposure over many decades to physical inactivity, unhealthy diets, smoking, lack of regular exercise, and possibly stress. This study assessed health-related physical fitness and risk factors associated with obesity among 1361 (boys: n=678; girls: n=683) primary school children aged 9-12 years in the Limpopo (LP) and Mpumalanga (MP) Provinces, South Africa. Anthropometric and physical fitness measurements were taken using the protocol of the International Society for the Advancement of Kinanthropometry (ISAK) (Marfell-Jones, et al., 2006) and EUROFIT (1988) test batteries. Body composition measures included body mass index (BMI) (weight/height2), percentage body fat (%BF) and waist-to-hip ratio, respectively. BMI for age and gender was used to classify the children as underweight, overweight or obese (Cole et al., 2007), whilst %BF calculated from the sum of two skinfolds (triceps and subscapular) using the equation of Slaughter et al. (1988) indicated adiposity. The International Physical Activity Questionnaire (IPAQ) was used to categorise the children’s physical activity (PA) level as follows: Low (METs scores of less than 500); Moderate (METs scores from 500 to 1499) or High (METs >1500). In general, 75% of the children were underweight/stunted and 1.6% overweight. Frequencies of underweight, normal weight and overweight were 77%, 22.4% and 0.2% in MP and 72%, 24% and 3% in LP province. Boys were generally taller and heavier than girls. At age 10 the MP boys performed significantly (p=0.05) better in sit-ups (SUP: 20.5 ±5.4) than the LP boys (18.6±6.56). However, the LP boys performed significantly better than the MP boys in sit-and-reach (SAR) at ages 10 and 11. The MP boys performed significantly (p=0.00) better in SBJ (121.6±9.1cm) compared to the Limpopo (118.4±11.00cm) boys at age 9. Generally, LP boys were significantly (p=0.00) better than the MP boys across all ages. The PA results showed that 27.7% (377), 58.5% (796) and 13.8% (188) of the children participate in low, moderate and high PA, respectively. Children in the MP province had higher PA (28.6%) in comparison to the low PA participation in LP children (26.7%). Furthermore, 59.7% of MP children compared to the LP children (57.3%) participate in moderate PA. A higher PA participation rate (15.8%) was found among the LP than MP children (11.6%). The girls had non-significantly higher BP values (systolic: 112.94±11.28mmHg; diastolic: (79.40±12.80mmHg) than boys (systolic: 110.71±14.95mmHg; diastolic: (75.53±12.53mmHg) who had higher PA levels (METs =1286.72±317.47) than girls (METs =397.28±30.14) (p<0.01). A total of 81% (n=1089) and 19% (n=253) of the combined samples had normal BP and prehypertension, respectively. When controlled for provinces, gender and age, results indicated that BMI was negatively associated with systolic BP (SBP) (-0.54) (p<0.01), but positively correlated with %BF (0.133) (p<0.01), whilst SBP related positively with %BF (0.125) (p<0.01). The children’s PA level correlated positively with BMI (0.86) (p<0.01) but negatively with %BF (-0.67); weight circumference (WC) (-0.41); SUP (sit-up) (-0.22); and predicted 2max • VO (-0.17) (p<0.05). The high percentage of underweight and pre-hypertensive children in the study warrants an urgent need to periodically evaluate PA levels among South African children and design appropriate intervention programmes to alleviate concerns over body weight disorders and low PA levels in children, thus optimising health outcomes. / PhD (Human Movement Science), North-West University, Potchefstroom Campus, 2015

This study investigates the responses of contemporary South African, Grade one children to threshold experiences in Grimm fairy tales and African Zulu folk tales. Thresholds involve an exciting or challenging experience, or a transformation in stories. Three stories from each genre were read over six sessions, to ten diverse black and white children, from one school. The children’s enjoyment was assessed, with focus on their backgrounds and previous knowledge, to help find beneficial reading for them. Results suggested that while gender of characters and story origins did not seem important, story length, humour, entertainment and educational ability, as well as personal involvement, were useful. The study supported the notion that stories are generally universal and could help bridge our cultural divide. Reader-Response theory was used and its principles helped to structure questions for the interviews, and to analyse data. Hopefully, the findings will help to select appropriate texts for all children beginning school in present-day South Africa.

AIM Poor iron status and under–nutrition among children are of concern not only in South Africa but worldwide. Both independent and combined associations between poor iron status, under–nutrition and cognitive development and function have been investigated. This mini–dissertation investigated possible associations between iron status indicators, anthropometric nutritional status and cognitive performance in the Beverage Fortified with Micronutrients (BeForMi) study population (black South African children aged 6–11 years in the North–West province of South Africa). METHODS The study was cross–sectional and based on the BeForMi study baseline data. Primary school children (n = 414) with the highest serum transferrin receptor (STR) and zinc protoporphyrin (ZnPP) levels were included. Anthropometric z–scores - BMI–for–age (BAZ), height–for–age (HAZ), and weight–for–age (WAZ) - and iron status indicators - haemoglobin (Hb), serum ferritin (SF), STR and ZnPP - were determined. The Kaufman Assessment Battery for Children, Second edition (KABC–II) was used to generate cognitive scores. RESULTS Fourteen percent of children were underweight (WAZ <= 2 SDs), 12.8% stunted (HAZ <= 2 SDs) and 8.4% wasted (BAZ <= 2 SDs). Of the children, 7.1% were anaemic (Hb < 11.5 g/dL), 13% iron depleted (Hb < 11.5 g/dL and SF < 12 ug/L) and 2.7% had iron deficiency anaemia (Hb < 11.5 g/dL and SF < 12 ug/L). Low iron stores (SF < 12 ug/L) were observed in 15.7% of the children. Positive correlations were found between SF and WAZ (r = 0.1, p = 0.047), Hb and HAZ (r = 0.13, p = 0.007) and WAZ (r = 0.13, p = 0.009). Positive correlations with small effect sizes were observed between some cognitive scores and z–scores (p < 0.05, r–value range 0.10 – 0.24). Negative correlations with small effect sizes were observed for the subtests Triangles and Rover (both subtests on simultaneous processing) with Hb (p = 0.008, r = –0.13) and SF (p = 0.04, r = –0.1) respectively. Higher HAZ, WAZ and education level of the head of household were all significantly associated with the likelihood that a child would fall within the upper quartile of Hb values in our study group (p = 0.036, p = 0.032 and p = 0.036 respectively). CONCLUSION The results suggested that under–nutrition was positively associated with poor iron status and lower cognitive scores in this study population. Further research, investigating specific effects of poor iron status at different stages of growth and the relationship with cognitive function later in life may help explain the negative correlations observed between current iron status indicators and cognitive scores. / Thesis (M.Sc (Dietetics))--North-West University, Potchefstroom Campus, 2011.

AIM Poor iron status and under–nutrition among children are of concern not only in South Africa but worldwide. Both independent and combined associations between poor iron status, under–nutrition and cognitive development and function have been investigated. This mini–dissertation investigated possible associations between iron status indicators, anthropometric nutritional status and cognitive performance in the Beverage Fortified with Micronutrients (BeForMi) study population (black South African children aged 6–11 years in the North–West province of South Africa). METHODS The study was cross–sectional and based on the BeForMi study baseline data. Primary school children (n = 414) with the highest serum transferrin receptor (STR) and zinc protoporphyrin (ZnPP) levels were included. Anthropometric z–scores - BMI–for–age (BAZ), height–for–age (HAZ), and weight–for–age (WAZ) - and iron status indicators - haemoglobin (Hb), serum ferritin (SF), STR and ZnPP - were determined. The Kaufman Assessment Battery for Children, Second edition (KABC–II) was used to generate cognitive scores. RESULTS Fourteen percent of children were underweight (WAZ <= 2 SDs), 12.8% stunted (HAZ <= 2 SDs) and 8.4% wasted (BAZ <= 2 SDs). Of the children, 7.1% were anaemic (Hb < 11.5 g/dL), 13% iron depleted (Hb < 11.5 g/dL and SF < 12 ug/L) and 2.7% had iron deficiency anaemia (Hb < 11.5 g/dL and SF < 12 ug/L). Low iron stores (SF < 12 ug/L) were observed in 15.7% of the children. Positive correlations were found between SF and WAZ (r = 0.1, p = 0.047), Hb and HAZ (r = 0.13, p = 0.007) and WAZ (r = 0.13, p = 0.009). Positive correlations with small effect sizes were observed between some cognitive scores and z–scores (p < 0.05, r–value range 0.10 – 0.24). Negative correlations with small effect sizes were observed for the subtests Triangles and Rover (both subtests on simultaneous processing) with Hb (p = 0.008, r = –0.13) and SF (p = 0.04, r = –0.1) respectively. Higher HAZ, WAZ and education level of the head of household were all significantly associated with the likelihood that a child would fall within the upper quartile of Hb values in our study group (p = 0.036, p = 0.032 and p = 0.036 respectively). CONCLUSION The results suggested that under–nutrition was positively associated with poor iron status and lower cognitive scores in this study population. Further research, investigating specific effects of poor iron status at different stages of growth and the relationship with cognitive function later in life may help explain the negative correlations observed between current iron status indicators and cognitive scores. / Thesis (M.Sc (Dietetics))--North-West University, Potchefstroom Campus, 2011.

Thesis (M.Sc. (Physiology)) -- University of Limpopo, 2016 / Cardiovascular diseases (CVDs) are major public health problems nowadays in Africa. From prospective studies, it is also known that risk factors for CVDs start early in life and increase morbidity and mortality in sub-Saharan African adults. Mostly the risk factors of CVDs are malnutrition and hypertension. Economic development in South Africa leads to lifestyle changes that contribute to a high prevalence of high blood pressure (BP) and malnutrition. However, little is known about the relationship of anthropometric indicators and BP in children from the developing countries. Therefore the aim of this study was to determine the association between anthropometrics indicators and BP among rural children in Ellisras area of Limpopo province, South Africa. All 1961 children (n=1029 boys, n=932 girls) aged 5-12 years underwent anthropometric and BP measurements using standard procedure. Receiver operating characteristics (ROC) curve was used to assess the ability of anthropometric indicators to discriminate children with high BP. ROC was used to determine the area under curve (AUC), cut-off value, sensitivity and specificity for underweight in children for each age and gender. Linear regression was used to assess the relationship between anthropometric indicators and BP. ROC curve showed that height (AUC = 0.700, 95%Cl 0.581 to 0.818), SH (AUC= 0.690, 95%Cl 0.573 to 0.786) and SH/H (AUC=0.670, 95% 0.533 to 0.807) can significantly (P<0.05) identify Ellisras children with hypertension. AUC for neck circumference (NC) (0.698), mid upper arm circumference (MUAC) (0.677) and body mass index (BMI) (0.636) for boys were statistically significant (P<0.05) for high systolic blood pressure (SBP), while in girls AUC of BMI was not significant (P>0.05) for high diastolic blood pressure (DBP). The regression analysis showed a positive significant (P<0.05) association of SBP with NC (β=0.764, 95%CI 0.475 to 1.052) and MUAC (β=1.286, 95% Cl 0.990 to 1.581) for unadjusted and adjusted age and gender. NC (β=0.628 95% Cl 0.303 to 0.953) and MUAC (β=1.351 95% CI 1.004 to 1.697) showed a significant association with SBP. However, MUAC had a significant association with DBP for both unadjusted and adjusted age and gender. Sitting height (SH) was significantly associated with SBP (β = 0.134, 95% Cl 0.210 to 0.416) and DBP (β = 0.088, 95% Cl 0.086 to 0.259) for unadjusted. After adjusted for age and gender, SH was significantly associated with both SBP (β = 0.161, 95% Cl 0.220 to 0.532) and DBP (β = 0.101, 95% Cl 0.066 to 0.329). There was a positive significant association between BP and anthropometric indicators in this population study, though the association of DBP and NC disappeared after adjustments for age and gender. Furthermore, there is a positive significant association between DBP and SBP with the components of height amongst Ellisras rural children. NC and MUAC are the simplest techniques with good interrater reliability and could be used to screen underweight in children. / Vrije University, Amsterdam, The netherlands University of Limpopo National Research Foundation (NRF)