Young South African Children Research Articles

Using vignettes to understand the social-emotional experiences of three-year-olds in diverse language contexts

In this article, we report on the educational experiences of young Afrikaans mother tongue South African children who are exposed to multilingual learning environments during their preschool years. We carried out phenomenological research using a vignette research design that provided observational, co-experiential data of the lived experiences of three-year-old boys as they engaged with formal and informal learning. We controlled vignette data that had been collected through observations, written teacher validation, and face-to-face interviews against existing literature to provide in-depth insights into the participants' different experiences of and within their learning environments. Findings indicate specific areas in which young children may need additional support in multilingual learning environments, in terms of 1) social-emotional security experienced in the learning environment, 2) intentional development of empathy for peers, 3) independence and initiative taking in informal settings, and 4) interactive communication. Although we focused on a South African context, these findings may inform future interventions to support children in multilingual language environments in their early years.

Early Childhood Violence Exposure Patterns in The Drakenstein Child Health Study (DCHS).

Background: Research has highlighted high rates of exposure to violence among South African youth. However, work to date has been largely cross-sectional, focused on violence exposure during the adolescence period, and has been limited to specific types of violence exposure. We examined violence exposure in South African preschool children between 3 and 6 years of age, capturing both direct and indirect forms of violence, and tested for potential sex differences across the several types of exposures. Methods: Lifetime direct and indirect exposure to domestic and community violence wasmeasured by parental report when children were 3.5 years (N = 530), 4.5 years (N = 749) and 6 years of age (N= 417) in a South African birth cohort located in a peri-urban community. Results: There are three main findings. First, a large proportion of children (72%-75%) were reported as having been exposed to some form of direct or indirect violent experience in their homes or communities from a young age. Second, there was significant polyvictimization, with 49% of the children being exposed to more than one type of violence by age 6. Third, by 4.5 years of age, there was evidence that boys were more likely than girls to be exposed to domestic victimisation (28% vs. 17%) and polyvictimization (38% vs. 28%). Conclusions: These findings highlight the high levels of violence exposure in young South African children, particularly among boys, and the need for prevention at both the community and individual levels.

Early Childhood Violence Exposure Patterns in The Drakenstein Child Health Study (DCHS)

Background: Research has highlighted high rates of exposure to violence among South African youth. However, work to date has been largely cross-sectional, focused on violence exposure during the adolescence period, and has been limited to specific types of violence exposure. We examined violence exposure in South African preschool children between 3 and 6 years of age, capturing both direct and indirect forms of violence, and tested for potential sex differences across the several types of exposures. Methods: Lifetime direct and indirect exposure to domestic and community violence was measured by parental report when children were 3.5 years (N = 530), 4.5 years (N = 749) and 6 years of age (N= 417) in a South African birth cohort located in a peri-urban community. Results: There are three main findings. First, a large proportion of children (72%-75%) were reported as having been exposed to some form of direct or indirect violent experience in their homes or communities from a young age. Second, there was significant polyvictimization, with 49% of the children being exposed to more than one type of violence by age 6. Third, by 4.5 years of age, there was evidence that boys were more likely than girls to be exposed to domestic victimisation (28% vs. 17%) and polyvictimization (38% vs. 28%). Conclusions: These findings highlight the high levels of violence exposure in young South African children, particularly among boys, and the need for prevention at both the community and individual levels.

Comparison of Several Prediction Equations Using Skinfold Thickness for Estimating Percentage Body Fat vs. Body Fat Percentage Determined by BIA in 6-8-Year-Old South African Children: The BC-IT Study.

Body composition measurement is useful for assessing percentage body fat (%BF) and medical diagnosis, monitoring disease progression and response to treatment, and is essential in assessing nutritional status, especially in children. However, finding accurate and precise techniques remains a challenge. The study compares %BF determined by bioelectrical impedance analysis (BIA) and calculated from available prediction equations based on skinfolds in young South African children. A cross-sectional study performed on 202 children (83 boys and 119 girls) aged 6-8 years. Height and weight, triceps and subscapular skinfolds were determined according to standard procedures. %BF was determined with BIA and three relevant available equations. SPSS analyzed the data using paired samples tests, linear regression, and Bland-Altman plots. Significant paired mean differences were found for BIA and Slaughter (t201 = 33.896, p < 0.001), Wickramasinghe (t201 = 4.217, p < 0.001), and Dezenberg (t201 = 19.910, p < 0.001). For all of the equations, the standards for evaluating prediction errors (SEE) were above 5. The Bland-Altman plots show relatively large positive and negative deviations from the mean difference lines and trends of systematic under- and over-estimation of %BF across the %BF spectrum. All three equations demonstrated a smaller %BF than the %BF measured by BIA, but the difference was smallest with the Wickramasinghe equation. In comparison, a poor SEE was found in the three %BF predicted equations and %BF derived from BIA. As such, an age-specific %BF equation incorporating criterion methods of deuterium dilution techniques or 'gold-standard' methods is needed to refute these findings. However, in the absence of developed %BF equations or 'gold-standard' methods, the available prediction equations are still desirable.

Fungal diversity in the gut microbiome of young South African children

BackgroundThe fungal microbiome, or mycobiome, is a poorly described component of the gut ecosystem and little is known about its structure and development in children. In South Africa, there have been no culture-independent evaluations of the child gut mycobiota. This study aimed to characterise the gut mycobiota and explore the relationships between fungi and bacteria in the gut microbiome of children from Cape Town communities.MethodsStool samples were collected from children enrolled in the TB-CHAMP clinical trial. Internal transcribed spacer 1 (ITS1) gene sequencing was performed on a total of 115 stool samples using the Illumina MiSeq platform. Differences in fungal diversity and composition in relation to demographic, clinical, and environmental factors were investigated, and correlations between fungi and previously described bacterial populations in the same samples were described.ResultsTaxa from the genera Candida and Saccharomyces were detected in all participants. Differential abundance analysis showed that Candida spp. were significantly more abundant in children younger than 2 years compared to older children. The gut mycobiota was less diverse than the bacterial microbiota of the same participants, consistent with the findings of other human microbiome studies. The variation in richness and evenness of fungi was substantial, even between individuals of the same age. There was significant association between vitamin A supplementation and higher fungal alpha diversity (p = 0.047), and girls were shown to have lower fungal alpha diversity (p = 0.003). Co-occurrence between several bacterial taxa and Candida albicans was observed.ConclusionsThe dominant fungal taxa in our study population were similar to those reported in other paediatric studies; however, it remains difficult to identify the true core gut mycobiota due to the challenges set by the low abundance of gut fungi and the lack of true gut colonising species. The connection between the microbiota, vitamin A supplementation, and growth and immunity warrants exploration, especially in populations at risk for micronutrient deficiencies. While we were able to provide insight into the gut mycobiota of young South African children, further functional studies are necessary to explain the role of the mycobiota and the correlations between bacteria and fungi in human health.

Perceptions of the South African 24-Hour Movement Guidelines for Birth to 5 Years: A Qualitative Study.

South Africa launched 24-hour movement guidelines for birth to 5years in 2018. Perceptions of these guidelines were assessed as part of the dissemination process with community-based organizations in 2019. Fifteen dissemination workshops were held with community-based organization representatives and a range of stakeholders. Discussions were held with workshop attendees (n = 281) to obtain qualitative feedback on the guidelines and workshop. Six follow-up focus groups (n = 28) were conducted to obtain additional feedback on the guidelines and their dissemination. Discussions and focus groups were thematically analyzed. Participants recognized the importance of the guidelines for the health and development of young South African children. Participants' perceptions of the guidelines were consistently positive. The participants acknowledged the alignment of the guidelines with other South African programs and initiatives, and that they addressed gaps. Screen time and sleep were identified as the behaviors needing particular attention among young South African children. The negative impact of COVID-19 on young children's movement behaviors was acknowledged, especially regarding screen time. These findings provide evidence of stakeholders' positive perceptions of the South African guidelines and support the dissemination and implementation of these guidelines for the promotion of early childhood health and development in South Africa.

Association between clinical and environmental factors and the gut microbiota profiles in young South African children

Differences in the microbiota in populations over age and geographical locations complicate cross-study comparisons, and it is therefore essential to describe the baseline or control microbiota in each population. This includes the determination of the influence of demographic, clinical and environmental factors on the microbiota in a setting, and elucidates possible bias introduced by these factors, prior to further investigations. Little is known about the microbiota of children in South Africa after infancy. We provide a detailed description of the gut microbiota profiles of children from urban Cape Town and describe the influences of various clinical and environmental factors in different age groups during the first 5 years of life. Prevotella was the most common genus identified in the participants, and after infancy, the gut bacteria were dominated by Firmicutes and Bacteroidetes. In this setting, children exposed to antibiotics and indoor cooking fires were at the most risk for dysbiosis, showing significant losses in gut bacterial diversity.

Sociocultural Factors Affecting Vocabulary Development in Young South African Children.

Sociocultural influences on the development of child language skills have been widely studied, but the majority of the research findings were generated in Northern contexts. The current crosslinguistic, multisite study is the first of its kind in South Africa, considering the influence of a range of individual and sociocultural factors on expressive vocabulary size of young children. Caregivers of toddlers aged 16 to 32 months acquiring Afrikaans (n = 110), isiXhosa (n = 115), South African English (n = 105), or Xitsonga (n = 98) as home language completed a family background questionnaire and the MacArthur-Bates Communicative Development Inventory (CDI) about their children. Based on a revised version of Bronfenbrenner’s (1977) ecological systems theory, information was obtained from the family background questionnaire on individual factors (the child’s age and sex), microsystem-related factors (the number of other children and number of adults in the child’s household, maternal level of education, and SES), and exosystem-related factors (home language and geographic area, namely rural or urban). All sociocultural and individual factors combined explained 25% of the variance in expressive vocabulary size. Partial correlations between these sociocultural factors and the toddlers’ expressive vocabulary scores on 10 semantic domains yielded important insights into the impact of geographic area on the nature and size of children’s expressive vocabulary. Unlike in previous studies, maternal level of education and SES did not play a significant role in predicting children’s expressive vocabulary scores. These results indicate that there exists an interplay of sociocultural and individual influences on vocabulary development that requires a more complex ecological model of language development to understand the interaction between various sociocultural factors in diverse contexts.

Teachers’ perspectives on the factors contributing to childhood adversity

ABSTRACT The aim of the study was to determine from teachers’ unique perspectives, the types of adversities young South African children are exposed to. The sample consisted of 135 primary school, foundation phase teachers from six different provinces. The data were collected by using an adversity checklist which also included an open-ended question. An overwhelming number of teachers (71%) identified divorce as the most prevalent adversity in the school context. The results suggest that the negative effects of divorce on the well-being of the child, conflict between separated/divorced parents, children left with relatives and long working hours are some of the unfavourable effects of divorce and separation that foundation phase teachers notice in school settings. The pastoral role of the teacher in identifying and supporting children exposed to adversity was also highlighted.

The impact of COVID-19 on the holistic development of young South African at-risk children in three early childhood care and education centres in a rural area

Early childhood care and education (ECCE) has gained recognition as an important means of promoting the holistic development of the inseparable social, emotional, cognitive and physical facets of education in the early childhood years. Since early childhood development poses challenges to many young children, the prolonged mandatory closure of ECCE centres during the national lockdown exposed many young children to the additional risk of being deprived of the continuity of learning, security, health and safety. This article draws from a research project in three Bafenyi ECCE centres in the rural area of Ikageng (Potchefstroom) in the North-West province of South Africa and focuses on how COVID-19 influences the holistic development of young children at risk. A qualitative approach was taken, following a participatory action-learning and action-research (PALAR) design where all participants collaborate as equal partners and construct their own meaning from experiences within the action-learning set (ALS) to advocate for change. Within a critical and transformative paradigm teacher-participants were encouraged to think critically about the holistic development of young children and to consider how collaboration could lead to social change. The data collection method was limited to the recorded group discussions of the ALS during Cycle 1 of the PALAR process. Given that positive environmental and contextual factors are able to lay the groundwork for holistic development in the early years, the African Ubuntu philosophy of compassion, respect and humanity was viewed as being suitable to serve as theoretical framework for the study. The findings highlight that, even during a lockdown, it vital that collaborative ways are found to harness the precious early years with a view not only to meeting these children’s needs but also to laying the foundation for a sustainable future. It is argued that if teachers were to apply the Ubuntu philosophy, they would learn how to make lifelong use of the acquired skills to improve the holistic well-being of young children on an ongoing basis.

The impact of cytokine levels in young South African children with and without HIV-associated acute lower respiratory infections.

Altered host immune responses are considered to play a key role in the pathogenesis of acute lower respiratory infections (ALRI). The existing literature on cytokine responses in ALRI is largely focussed on adults from developed countries and there are few reports describing the role of cytokines in childhood ALRI, particularly in African or human immunodeficiency virus (HIV)-infected populations. To measure systemic cytokine levels in blood plasma from young South African children with and without ALRI and with and without HIV to determine associations between cytokine responses and disease status and respiratory viral identification. Blood plasma samples were collected from 106 hospitalized ALRI cases and 54 non-ALRI controls less than 2 years of age. HIV status was determined. Blood plasma concentrations of 19 cytokines, 7 chemokines, and 4 growth factors (epidermal growth factor, fibroblast growth factor-basic, hepatocyte growth factor, and vascular endothelial) were measured using The Human Cytokine 30-Plex Panel. Common respiratory viruses were identified by PCR. Mean cytokine concentrations for G-CSF, interferon (IFN)-γ, interleukin (IL)-5, and MCP-1 were significantly higher in ALRI cases than in nonrespiratory controls. Within the ALRI cases, several cytokines were higher in children with a virus compared with children without a virus. Mean cytokine concentrations for IFN-α, IFN-γ, IL-4, IL-5, IL-13, tumour necrosis factor-α, and MIP-1α were significantly lower in HIV-infected cases than in HIV-uninfected cases, while IP-10 and monokine induced by interferon-γ were significantly higher in HIV-infected cases than in HIV-uninfected cases. Certain cytokines are likely to play an important role in the host immune response to ALRI. HIV-infected children have impaired inflammatory responses to respiratory infections compared with HIV-uninfected children.

Screening for overweight using mid-upper arm circumference (MUAC) among children younger than two years in the Eastern Cape, South Africa

Background: The relationship between overweight and under-nutrition, particularly in resource-poor settings, poses practical challenges for targeting nutrition interventions. Current anthropometric indicators including weight for length (WLZ) recommended by the WHO may be challenging in community settings. Objectives: The aim of this study was to assess whether MUAC can accurately identify children aged younger than two years with overweight and obesity. Method: A descriptive, cross-sectional study was used to collect data from a non-probability sample of 397 young South African children from October 2015 to February 2016. MUAC cut-off values were tested using a receiver operating characteristic and area under the curve (AUC). Results: The prevalence of overweight (WLZ > +2) and obesity (WLZ > +3) was 11% (n = 44) and 5% (21) respectively. A MUAC cut-off value for identifying male children 6 to 24 months old with overweight was determined at 16.5 cm (85% sensitivity, 71.4% specificity, AUC = 0.821) and female children at 16.5 cm (100% sensitivity, 76.6% specificity, AUC = 0.938). Conclusions: MUAC may be an appropriate tool for identifying children younger than two years old with overweight and obesity. The predicted MUAC cut-off values were able to identify infants and young children with overweight accurately.

Developing mindfulness in children through participation in music activities

The vast majority of young South African children grow up in socially- and economicallychallenging settings. These impeding conditions hamper their intellectual growth and affect their physical, mental, emotional and spiritual well-being. Increasingly, mindfulness is being recognised as a means to enhance holistic well-being of children. Likewise, music is widely acknowledged for its potential contribution to the holistic development of children. In this article, we reflect on a non-formal music programme, implemented on a weekly basis over a period of 10 months, at an aftercare facility in an impoverished township area in South Africa. Our aim was to develop, through the children’s active participation in music activities, some aspects of mindfulness. Data were generated through personal observations, field notes and semi-structured interviews. Two salient themes emerged, namely, enhanced awareness of self and others, and improved listening and attention skills. These are key aspects of mindfulness. We subsequently argue that aspects of mindfulness in young children can be developed through focused activities centred on music and sound.

Screening for Mental Health Among Young South African Children: the Use of the Strengths and Difficulties Questionnaire (SDQ)

Little is known about the prevalence of child mental health (MH) problems in sub-Saharan Africa, where poverty, HIV, and family disruption increase risk. One barrier is the lack of MH assessment tools lay staff can validly and reliably administer in settings with few MH professionals. In a South African (SA) peri-urban cohort, we examined psychometric properties of the Strengths and Difficulties Questionnaire (SDQ), a widely used measure of child emotional and behavioral functioning. Data come from a large population-based study (N=1581) of children 4-6 years old. Lay fieldworkers administered the SDQ in isiZulu to caregivers at baseline and two years later. Exploratory factor analysisexamined whether the established SDQ five-factor structure and Total Difficulties score would be replicated. The psychometric model was tailored for ordinal items, and target factor rotation was used. Total Difficulties, Emotional symptoms and Prosocial behavior factors were supported, with partial support for Conduct problems. Peer relationships and Hyperactivity/inattentive subscale items loaded poorly. Subscale Cronbach's alphas ranged from 0.29 (Peers) to 0.62 (Emotional). Internal consistency of Total Difficulties score was acceptable (0.74); 30% scored in the abnormal range on Total Difficulties, based on UK norms. SDQ scores in our sample suggest young children in SA are at high risk for MH problems. The SDQ, particularly the Total Difficulties score, may be a useful screening tool in SA. Yet, some subscales did not work in this language and context; if social skills and hyperactivity/inattention arebeing considered, modification or additional measures may be needed.

Anxiety-Proneness, Anxiety Symptoms, and The Role of Parental Overprotection in Young South African Children

This study examined anxiety in preschool children within a South-African context. The parents and teachers of 101 South African children aged 2 to 6 years completed measures of children's anxiety-prone temperament (behavioral inhibition) and anxiety disorders symptoms. Parents and teachers of 59 children could be re-approached one year later, with the request to fill in both scales again, while parents at that time also completed a measure of parental overprotection. Results indicated that, compared with normative scores collected in Western countries, young South African children displayed relatively high levels of anxiety-proneness and anxiety disorders symptoms, although this cultural difference could only be demonstrated when using the parentreport data. Further, on both occasions there were substantial and positive correlations between children's behavioral inhibition and anxiety symptoms. Behavioral inhibition and anxiety symptoms, in particular when assessed by parent report, appeared to be fairly stable during the one-year period, and we found only tentative support for the idea that behavioral inhibition on time 1 increased the risk for anxiety symptoms on time 2. Finally, a cross-sectional analysis of the data collected on time 2 revealed a positive correlation between overprotection and children's anxiety symptoms as well as a marginally significant interaction of behavioral inhibition and overprotection on children's anxiety symptoms, indicating that in particular the combination of high behavioral inhibition and high overprotection tended to be associated with the highest anxiety levels.

Early detection of autism spectrum disorder in young isiZulu-speaking children in South Africa.

Culturally appropriate tools are needed for detecting symptoms of autism spectrum disorder in young South African children. The objectives of this study were to (1) adapt and translate into isiZulu existing measures for detecting early signs of autism spectrum disorder, (2) use the measures to characterize and compare behavioural profiles of young isiZulu-speaking children with and without autism spectrum disorder and (3) compare symptom profiles across sampling procedures. Measures were translated and adapted into isiZulu and used to evaluate 26 isiZulu-speaking children, 15 children with no reported developmental concerns and 11 referred for suspected autism spectrum disorder. A video-recorded observation of children and caregivers in their home environment was also made. Based on best-estimate diagnoses, 10 children were classified as autism spectrum disorder and 16 as non-autism spectrum disorder. The children with autism spectrum disorder presented with significantly more autism spectrum disorder red flags than the non-autism spectrum disorder group according to parent report and systematic ratings of red flags. Significant correlations between parent report and observational measures of red flags were observed. More red flags were observed during structured evaluations than home observations in the autism spectrum disorder group. Findings provide a foundation for tool translation and adaptation in South Africa and identifying social communication markers to detect autism spectrum disorder in young isiZulu-speaking children.

Respiratory viruses in young South African children with acute lower respiratory infections and interactions with HIV

BackgroundHuman rhinovirus (RV) is the most common respiratory virus and has been associated with frequent and severe acute lower respiratory infections (ALRI). The prevalence of RV species among HIV-infected children in South Africa is unknown. ObjectivesTo describe the prevalence of respiratory viruses, including RV species, associated with HIV status and other clinical symptoms in children less than two years of age with and without ALRI in Pretoria, South Africa. Study designNasopharyngeal aspirates were collected from 105 hospitalized ALRI cases and 53 non-ALRI controls less than two years of age. HIV status was determined. Common respiratory viruses were identified by PCR, and RV species and genotypes were identified by semi-nested PCR, sequencing and phylogenetic tree analyses. ResultsRespiratory viruses were more common among ALRI cases than controls (83.8% vs. 69.2%; p=0.041). RV was the most commonly identified virus in cases with pneumonia (45.6%) or bronchiolitis (52.1%), regardless of HIV status, as well as in controls (39.6%). RV-A was identified in 26.7% of cases and 15.1% of controls while RV-C was identified in 21.0% of cases and 18.9% of controls. HIV-infected children were more likely to be diagnosed with pneumonia than bronchiolitis (p<0.01). RSV was not identified in any HIV-infected cases (n=15) compared with 30.6% of HIV-uninfected cases (n=85, p=0.013), and was identified more frequently in bronchiolitis than in pneumonia cases (43.8% vs. 12.3%; p<0.01). ConclusionsRV-A and RV-C are endemic in South African children and HIV infection may be protective against RSV and bronchiolitis.

Telling stories and adding scores: Measuring resilience in young children affected by maternal HIV and AIDS

“Telling stories and adding scores: Measuring resilience in young children affected by maternal HIV and AIDS”, demonstrates how a concurrent mixed method design assisted cross-cultural comparison and ecological descriptions of resilience in young South African children, as well as validated alternative ways to measure resilience in young children. In a longitudinal randomised control trial, which investigated psychological resilience in mothers and children affected by HIV/AIDS, we combined a qualitative projective story-telling technique (Düss Fable) with quantitative data (Child Behaviour Checklist). The children mostly displayed adaptive resilience-related behaviours, although maladaptive behaviours were present. Participating children use internal (resolve/agency, positive future expectations, emotional intelligence) and external protective resources (material resources, positive institutions) to mediate adaptation. Children's maladaptive behaviours were exacerbated by internal (limited problem-solving skills, negative emotions) and external risk factors (chronic and cumulative adversity).

Performance of EAL learners on a non-South African Articulation Test (GFTA-2)

:Research on the various aspects of child language development in South Africa has generally been an area neglected by specialists in the study of language. In South Africa's multilingual urban settings, English is the language of mutual understanding in most classrooms. The assessment of language (including speech sound production) in English additional language (EAL) pre-schoolers is hampered by the fact that insufficient standardised resources are available for use with young multilingual South African children. Research indicates that the Goldman-Fristoe Test of Articulation – Second Edition (GFTA-2) is a popular formal assessment instrument used for assessing children's articulation abilities by many speech-language therapists in South Africa. The study described the performance of English second language learners, aged between four and nine years, on the GFTA-2 in an urban region in the Gauteng province of South Africa. A descriptive, dominant-less-dominant model research design was used. No significant difference in performance between the second language learners and the normative indicators was noted. The results illustrate the need to adapt the GFTA-2 for the South African context.

Assessment of physical activity and sedentary behavior at preschools in Cape Town, South Africa.

Overweight and obesity among young South African (SA) children have reached concerning levels. Preschool interventions to promote physical activity (PA) and reduce sedentary behavior (SB) could help curb these trends. However, research has not been conducted to assess these behaviors in SA preschools and how these might differ across income settings. This study aimed to (1) assess, by direct observation, PA and SB patterns of children in a range of preschool settings; (2) determine the influence of socioeconomic status on PA and SB; and (3) identify contextual and individual-level factors associated with PA. Eighty children (4-5 years old) from four low-income and four mid-/high-income preschools in Cape Town were observed using the Observational System for Recording Physical Activity in Children-Preschool Version. Children spent 73% of their time engaged in SB. Low-income children spent 93% of their time indoors, compared to 79% among mid-/high-income children (p<0.001). Low-income children spent 11% of their time in moderate-to-vigorous PA (MVPA), compared to 8% among mid-/high-income children (p<0.05). Children across all settings were significantly more likely to engage in light PA (LPA) and MVPA if they were outside (relative risk ratio [RRR]=2.48 for LPA; RRR=6.95 for MVPA) and if their activity was adult-initiated (RRR=1.74 for LPA; RRR=1.66 for MVPA). Obese children were significantly less likely to do LPA (RRR=0.47); underweight children were significantly less likely to do LPA (RRR=0.63) and MVPA (RRR=0.26). These findings provide information useful for the development of interventions to address PA and SB in SA preschool children.