Urban South African Children Research Articles

S-43-6: HYPERTENSION FROM CHILDHOOD TO ADULTHOOD: THE BT20+ STUDY

Background: Hypertension is a major risk factor for cardiovascular diseases and its prevalence among the Sub-Saharan African population has risen extremely in the last decades. Moreover, there is growing evidence that suggest that hypertension has its roots in childhood and adolescence and persist into adulthood. However, the epidemiology of hypertension in the young in a Low to Middle Income Country (LMIC) setting is not fully understood due to paucity of longitudinal data. Thus, we sought to investigate prevalence and new cases of hypertension and to identify risk factors that predict the incidence of hypertension from early childhood in urban black South-African children. Methods: We used data from the Birth to Twenty (BT20+) cohort in Johannesburg, South Africa. This cohort comprised of children born in 1990 and who had their growth, development and blood pressure measured at six follow-up periods over the course of 13 years. Hypertension status was classified using the fourth report of the National High Blood Pressure Education Program. Hypertension incidence rate was calculated using staggered entry survival analysis. We identified risk factors for incident hypertension using multivariable cox proportional hazard regressions. Results: Over a follow-up period of 13 years, the overall point prevalence of hypertension ranged from 8.4 to 24.4 % and cumulative incidence of hypertension was 54.3% (95% CI: 51.8 to 56.8). The overall hypertension incidence rate was 57.0 cases per 1000 person-years (95% CI: 53.2 to 61.1). Furthermore, the risk for incident hypertension increased with a rapid relative weight gain in early childhood (aHR = 1.11, 95% CI: 1.00 to 1.22), in mid childhood (aHR = 1.13, 95% CI: 1.03 to 1.24) and in adolescence (aHR = 1.21, 95% CI: 0.99 to 1.47). An increase in maternal parity significantly increased the risk for incident hypertension (aHR = 1.08, 95% CI: 1.01 to 1.15). Conclusion: Rapid weight gain relative to height and higher parity are prominent risk factors for incident hypertension in urban black South African children and adolescents. In order to reduce the high incidence and the disease burden of hypertension, national health programs should focus on promoting healthy lifestyle in early stages of life to curb rapid weight gain. Further research is required to check whether incident hypertension in childhood predict clinical outcomes in adulthood.

Incidence and correlates of high blood pressure from childhood to adulthood: the Birth to Twenty study.

Background:There is growing evidence from high-income countries suggesting that hypertension developed in childhood and adolescence persists into adulthood. The objective of this study was to investigate the incidence and risk factors of high blood pressure (BP) in urban black children.Methods:We used data from the Birth to Twenty (BT20+) cohort in Johannesburg, South Africa constituting of children born in 1990 and who had their growth, development and blood pressure measured at six follow-up periods over the course of 13 years. High BP was classified as at least 95th percentile for age, sex and height. Incidence rate of high BP was calculated using survival analysis and risk factors were determined by use of Cox proportional hazard regression.Results:Over a follow-up period of 13 years, the overall incidence rate of high BP was 57 cases per 1000 person-years (95% CI 53.2–61.1). Risk for incident high BP increased with rapid relative weight gain in early childhood (hazard ratio =1.11, 95% CI 1.00–1.22), mid-childhood (hazard ratio = 1.13, 95% CI 1.03–1.24) and adolescence (hazard ratio = 1.21, 95% CI 0.99–1.47). Maternal parity significantly increased the risk for incident high BP (hazard ratio = 1.08, 95% CI 1.01–1.15).Conclusion:Maternal parity and relative weight gain were determinants for incident high blood pressure in urban black South African children and adolescents. To reduce the high incidence and the disease burden of high BP, national programs should focus on promoting healthy lifestyle in early stages of life to prevent rapid weight gain and later cardiovascular disease risk. Further research is required to investigate whether incident high BP in childhood predict clinical outcomes in adulthood.

Environment-dependent alterations of immune mediators in urban and rural South African children with atopic dermatitis.

In order to improve targeted therapeutic approaches for children with atopic dermatitis (AD), novel insights into the molecular mechanisms and environmental exposures that differentially contribute to disease phenotypes are required. We wished to identify AD immunological endotypes in South African children from rural and urban environments. We measured immunological, socio-economic and environmental factors in healthy children (n = 74) and children with AD (n = 78), in rural and urban settings from the same ethno-linguistic AmaXhosa background in South Africa. Circulating eosinophils, monocytes, TARC, MCP-4, IL-16 and allergen-specific IgE levels were elevated, while IL-17A and IL-23 levels were reduced, in children with AD regardless of their location. Independent of AD, children living in a rural environment had the highest levels of TNFα, TNFβ, IL-1α, IL-6, IL-8, IL-21, MCP-1, MIP-1α, MIP-1β, MDC, sICAM1, sVCAM1, VEGFA, VEGFD and Tie2, suggesting a generalized microinflammation or a pattern of trained immunity without any specific TH polarization. In contrast, IL-15, IL-22, Flt1, PIGF and βFGF were highest in urban children. Rural healthy children had the lowest levels of food allergen-specific IgG4. Early life nutritional factors, medications, animal exposures, indoor environment, sunlight exposure, household size, household income and parental education levels were associated with differences in circulating cytokine levels. This study highlights the immunological impact of environmental exposures and socio-economic status in the manifestation of immune endotypes in children with AD living in urban and rural areas, which are important in selecting appropriately matched immunological therapies for treatment of AD.

Parent perspectives on preschoolers' movement and dietary behaviours: a qualitative study in Soweto, South Africa.

Childhood obesity is of increasing concern in South Africa, and interventions to promote healthy behaviours related to obesity in children are needed. Young children in urban low-income settings are particularly at risk of excess adiposity. The current study aimed to describe how parents of preschool children in an urban South African township view children's movement and dietary behaviours, and associated barriers and facilitators. A contextualist qualitative design was utilised with in-depth interviews conducted in the home setting and analysed using reflexive thematic analysis. Field notes were used to contextualise findings. Four neighbourhoods in a predominantly low-income urban township. Sixteen parents (fourteen mothers, two fathers) of preschool-age children were recruited via preschools. Four themes were developed: children's autonomy and the limits of parental control; balancing trust and fears; the appeal of screens; and aspirations and pressures of parenthood. Barriers to healthy behaviours included children's food preferences, aspirations and pressures to consume unhealthy foods, other adults giving children snacks, lack of safe places to play, unhealthy food environments and underlying structural factors. Facilitators included set routines, the preschool environment, safe places to play and availability of healthy foods. Low-income families in Soweto face many structural challenges that cannot easily be addressed through public health interventions, but there may be opportunities for behavioural interventions targeting interpersonal and organisational aspects, such as bedtime routines and preschool snacks, to achieve positive changes. More research on preschoolers' movement and dietary behaviours, and related interventions, is needed in South Africa.

Environmental factors associated with allergy in urban and rural children from the South African Food Allergy (SAFFA) cohort

The prevalence of allergic diseases differs in urban and rural populations. We sought to assess associations between environmental and dietary factors with allergic diseases in urban and rural South African children. Toddlers aged 12 to 36 months were assessed for food allergen and aeroallergen sensitization, atopic dermatitis, allergic rhinitis, asthma, and challenge-proved food allergy. Information was collected on family history of allergic diseases, household size, socioeconomic status, delivery mode, antibiotic and probiotic use, exposure to fermented and unpasteurized milk, antihelminth treatment, sunlight exposure, pet and farm animal exposure, cigarette smoke, and household cooking and heating fuels. Antenatal exposures to pets, livestock, and cigarette smoke were assessed. Asubsection completed questions on consumption of fruits and vegetables, fast foods, soft drinks/fruit juices, and fried/microwaved meat. Risk and protective factors differed between urban and rural settings. Exposure to farm animals in infants and their mothers during pregnancy was protective against allergic outcomes in the rural population. Consumption of unpasteurized milk is uncommon in this group of rural children and is unlikely to be an important factor in rural protection. In urban children birth by cesarean section is associated with food allergy, and consumption of fermented milk products is associated with reduced asthma and atopic dermatitis. In both cohorts antenatal maternal smoking and environmental smoking exposure were predominantly associated with asthma, and consumption of fast foods and fried meats were associated with allergy. In this rural environment exposure to livestock is the strongest protective factor. In urban communities, where animal contact is rare, risk factors include cesarian section, and protective factors include consumption of fermented milk products. Modifiable risk factors urgently require interventionsto prevent increasing allergy rates in countries undergoing rapid urbanization.

The prevalence of malnutrition and growth percentiles for urban South African children

BackgroundLow- and middle-income countries (LMIC) are experiencing a double-burden of malnutrition characterised by high prevalence of both under- and over-nutrition. We set out using data from the mixed-longitudinal Birth-to-Twenty Plus (Bt20+) birth cohort, to evaluate the patterns of malnutrition and growth in a large South African (SA) city by; (i) assessing the prevalence of undernutrition from birth to 5 years of age and overweight and obesity from ages 2 to 21 years in black and white, male and female children, and (ii) determining percentiles for height, weight, BMI, waist and hip circumferences and comparing the centiles to American and Dutch references.MethodsHeight, weight, waist and hip circumferences were measured on urban black and white SA children from the Bt20+. A total of 3273 children born between April and June 1990 in the Greater Johannesburg Metropolitan area were included in the cohort. Z-scores were derived using the WHO 2006 child growth standards (0–5 years), for defining stunting, underweight and wasting. The International Obesity Task Force (IOTF) references were used to define overweight and obesity. Percentiles were developed using the lambda mu sigma (LMS) method and compared to American and Dutch references.ResultsBlack children were consistently shorter and black males lighter than white children and American references. The prevalence of stunting peaked at 2 years and was significantly higher in males than females and in black than white children. Black females had a greater prevalence of overweight and obesity than black males from 10 to 17 years. The percentiles for black females for weight and BMI were similar to those of South African white and American references but both black and white South African females had lower waist circumferences than American references.ConclusionThe growth percentiles show that young South African urban black females are experiencing general but not central obesity due to a secular change which is faster in weight than height. High levels of undernutrition persist alongside high levels of over-nutrition with adolescence being a critical period for the upsurge in obesity in females. Early intervention is needed to combat the rise in obesity.

Genetic risk score for adult body mass index associations with childhood and adolescent weight gain in an African population

BackgroundNinety-seven independent single nucleotide polymorphisms (SNPs) are robustly associated with adult body mass index (BMI kg/m2) in Caucasian populations. The relevance of such variants in African populations at different stages of the life course (such as childhood) is unclear. We tested whether a genetic risk score composed of the aforementioned SNPs was associated with BMI from infancy to early adulthood. We further tested whether this genetic effect was mediated by conditional weight gain at different growth periods. We used data from the Birth to Twenty Plus Cohort (Bt20+), for 971 urban South African black children from birth to 18 years. DNA was collected at 13 years old and was genotyped using the Metabochip (Illumina) array. The weighted genetic risk score (wGRS) for BMI was constructed based on 71 of the 97 previously reported SNPs.ResultsThe cross-sectional association between the wGRS and BMI strengthened with age from 5 to 18 years. The significant associations were observed from 11 to 18 years, and peak effect sizes were observed at 13 and 14 years of age. Results from the linear mixed effects models showed significant interactions between the wGRS and age on longitudinal BMI but no such interactions were observed in sex and the wGRS. A higher wGRS was associated with an increased relative risk of belonging to the early onset obese longitudinal BMI trajectory (relative risk = 1.88; 95%CI 1.28 to 2.76) compared to belonging to a normal longitudinal BMI trajectory. Adolescent conditional relative weight gain had a suggestive mediation effect of 56% on the association between wGRS and obesity risk at 18 years.ConclusionsThe results suggest that genetic susceptibility to higher adult BMI can be tracked from childhood in this African population. This supports the notion that prevention of adult obesity should begin early in life. The genetic risk score combined with other non-genetic risk factors, such as BMI trajectory membership in our case, has the potential to be used to screen for early identification of individuals at increased risk of obesity and other related NCD risk factors in order to reduce the adverse health risk outcomes later.

A longitudinal perspective on violence in the lives of South African children from the Birth to Twenty Plus cohort study in Johannesburg-Soweto

Background. Violence against children is a significant cause of personal suffering and long-term ill health, poor psychological adjustment, and a range of social difficulties, including adverse effects intergenerationally. Objectives. Using a large corpus of longitudinal data collected in the Birth to Twenty Plus cohort, to give an overview of exposure to and experience of violence, as well as perpetration of violence, across childhood, reported contemporaneously by several informants. This overcomes limitations of retrospectively recalled information collected from one person at one point in time. Methods. We identified 280 data points relating to exposure to and perpetration of violence in 14 of the 21 waves of data collection from birth to 22 years of age. Data were classified into four developmental stages (preschool, primary school years, adolescence and young adulthood) and seven categories (exposure to violence in the community, home and school; exposure to peer violence; being a victim of violence, excluding sexual violence; sexual violence; and perpetration of violence). Both descriptive and inferential statistics were employed to analyse the data. Results. Over the past two decades, only 1% of the sample had not been exposed to or experienced violence in their home, school and/or community. Two-thirds of children of schoolgoing age were reported as having been exposed to community violence, and more than half of all children to violence in their home. Reports of sexual violence increased from 10% among primary school-aged children to ~30% among adolescents and young adults. Over the course of their lives, ~40% of children were reported as having been exposed to or being victims of five or six of the categories of violence coded in this analysis. High levels of violence perpetration were reported across childhood. Age and gender differences in exposure to and experience and perpetration of violence were evident, and all categories of violence were more prevalent among poorer and more disadvantaged groups. Conclusions. Very high levels of violence were reported in all the settings of urban South African children’s lives: home, community, school, among peers and in their intimate relationships. Children and youth were also reported to perpetrate high levels of violence. The personal and social costs of violence are very high, resulting in major public health problems due to its avoidable effects on short- and long-term mental and physical health and social adjustment, and intergenerationally.

A longitudinal perspective on violence in the lives of South African children from the Birth to Twenty Plus cohort study in Johannesburg-Soweto.

Violence against children is a significant cause of personal suffering and long-term ill health, poor psychological adjustment, and a range of social difficulties, including adverse effects intergenerationally. Using a large corpus of longitudinal data collected in the Birth to Twenty Plus cohort, to give an overview of exposure to and experience of violence, as well as perpetration of violence, across childhood, reported contemporaneously by several informants. This overcomes limitations of retrospectively recalled information collected from one person at one point in time. We identified 280 data points relating to exposure to and perpetration of violence in 14 of the 21 waves of data collection from birth to 22 years of age. Data were classified into four developmental stages (preschool, primary school years, adolescence and young adulthood) and seven categories (exposure to violence in the community, home and school; exposure to peer violence; being a victim of violence, excluding sexual violence; sexual violence; and perpetration of violence). Both descriptive and inferential statistics were employed to analyse the data. Over the past two decades, only 1% of the sample had not been exposed to or experienced violence in their home, school and/or community. Two-thirds of children of schoolgoing age were reported as having been exposed to community violence, and more than half of all children to violence in their home. Reports of sexual violence increased from 10% among primary school-aged children to ~30% among adolescents and young adults. Over the course of their lives, ~40% of children were reported as having been exposed to or being victims of five or six of the categories of violence coded in this analysis. High levels of violence perpetration were reported across childhood. Age and gender differences in exposure to and experience and perpetration of violence were evident, and all categories of violence were more prevalent among poorer and more disadvantaged groups. Very high levels of violence were reported in all the settings of urban South African children's lives: home, community, school, among peers and in their intimate relationships. Children and youth were also reported to perpetrate high levels of violence. The personal and social costs of violence are very high, resulting in major public health problems due to its avoidable effects on short- and long-term mental and physical health and social adjustment, and intergenerationally.

Considerations when assessing urban South African children with the Developmental Test of Visual Perception 2nd edition (DTVP-2)

INTRODUCTION: The Developmental Test of Visual Perception second Edition (DTVP-2) is frequently used by South African (SA) occupational therapists, despite the suitability of its US-based norms for SA children being questioned, and the 2014 release of the updated DTVP-3. This study investigated the suitability of the DTVP-2 norms for SA English-speaking children aged 5y 6mo-5y 11mo. SA sample scores were compared to American norms. Motor-reduced subtest scores were compared with and without the stop rule. Gender differences were tested. METHODS: A quantitative, descriptive study used 134 English speaking children. Motor-enhanced subtests were administered as prescribed, but motor-reduced subtests were administered without the prescribed stop rule, allowing prescribed and adapted scores to be computed. RESULTS: Scores of SA children varied from American norms, especially in visual closure, visual-motor speed and form constancy. Better visual closure scores were obtained when the stop rule was excluded. Boys and girls differed only on figure-ground, where girls scored higher. CONCLUSION: The DTVP-2 is valuable, but caution is recommended when measuring visual perceptual skills for this age band. Alternative instruments should be used, or local norms, or even more contextually relevant instruments, must be developed locally. At least, occupational therapists should apply US norms with care. Key words: Developmental Test of Visual Perception 2nd edition (DTVP-2); visual perceptual skills; 5-year-old children; urban South Africa; suitability

Early life risk exposure and stunting in urban South African 2-year old children.

Stunting is a measure of overall nutritional status and is a major public health concern because of its association with child mortality and morbidity and later adult performance. This study examined the effects of pregnancy events, birth characteristics and infant risk exposure on stunting at age 2 years. The study, established in 1990 in Soweto, an urban South African township, included 1098 mother-infant pairs enroled in the Birth to Twenty Plus longitudinal birth cohort study. In total, 22% of children were stunted at age 2 years, with males at greater risk than females [24.8 v. 19.4%, odds ratio (OR)=1.38; 95% confidence interval (CI): 1.03, 1.83]. In unadjusted analysis, male sex, household socio-economic status (SES), overcrowding, maternal age, maternal education, single motherhood, ethnicity, birth weight, gestational age and duration of infant breastfeeding were all significantly associated with stunting. In multivariable analysis, higher birth weight was protective against stunting for both sexes. Higher maternal education was protective for females only (adjusted odds ratio (AOR)=0.35; 95% CI: 0.14, 0.87), whereas wealthier household SES protected males (AOR for richest SES group=0.39; 95% CI: 0.16, 0.92). In this and other similar settings, current stunting prevention efforts focussing on primarily providing targeted proximal interventions, such as food supplements, risk undermining the critical importance of addressing key distal determinants of stunting such as SES and maternal education.

Hearing loss in urban South African school children (grade 1 to 3)

ObjectiveThis study aimed to describe the prevalence and characteristics of hearing loss in school-aged children in an urban South African population. MethodChildren from grade one to three from five schools in the Gauteng Province of South Africa formed a representative sample for this study. All children underwent otoscopic examinations, tympanometry and pure tone screening (25dB HL at 1, 2 and 4kHz). Children who failed the screening test and 5% of those who passed the screening test underwent diagnostic audiometry. ResultsA total of 1070 children were screened. Otoscopic examinations revealed that a total of 6.6% ears had cerumen and 7.5% of ears presented with a type-B tympanogram. 24 children (12 male, 12 female) were diagnosed with hearing loss. The overall prevalence of hearing loss was 2.2% with Caucasian children being 2.9 times more (95% confidence interval, 1.2–6.9) likely to have a hearing loss than African children. ConclusionHearing loss prevalence in urban South African school-aged children suggest that many children (2.2%) are in need of some form of follow-up services, most for medical intervention (1.2%) with a smaller population requiring audiological intervention (0.4%).

Blood pressure tracking in urban black South African children: birth to twenty cohort.

BackgroundHypertension is an emerging public health problem in South Africa. Recent evidence from longitudinal studies has shown that hypertension in adulthood can be traced back to childhood. There is scarcity of longitudinal data on paediatric blood pressure (BP) particularly in African populations. The objective of this study is to assess the prevalence of hypertension and evaluate BP tracking between childhood and late adolescence among South African black Children.MethodsThis study utilized data from the Birth to Twenty cohort, which is comprised of children born in Soweto, Johannesburg in 1990 (N = 3273, 78.5 % black). Data on BP and anthropometry were collected at six follow-up periods between ages 5 and 18 years. Blood pressure status was classified using the Fourth report on National High Blood pressure program in children and adolescents. Pearson correlation coefficients and relative risk ratios (RR) were used to describe tracking of BP between childhood and late adolescence.ResultsThe overall point prevalence ranged from 9.2 to 16.4 % for prehypertension and 8.4 to 24.4 % for hypertension. Tracking coefficients ranged from 0.20 to 0.57 for SBP and 0.17- 0.51 for DBP in both sexes over the 14 years of measurement. The proportion of children who maintained an elevated BP status between childhood, adolescence and age 18 years ranged from 36.1 % at age 5 years to 56.3 % at age 13 years. Risk of having elevated BP at 18 years ranged from; RR: 1.60 (95 % CI: 1.29–2.00) at 5 years to RR: 2.71 (95 % CI: 2.32–3.17) at 14 years of age.ConclusionsThis study reports high prevalence of elevated BP which tracks from early childhood into late adolescence. These findings emphasize the importance of early identification of children at risk of developing elevated BP and related risk factors plus timely intervention to prevent hypertension in adulthood.

Blood pressure tracking in urban black South African children: birth to twenty cohort

Blood pressure tracking in urban black South African children: birth to twenty cohort

Body fat percentage of urban South African children: implications for health and fitness.

To explore gender and racial profiling of percentage body fat of 1136 urban South African children attending public schools in Pretoria Central. This is a cross-sectional survey of 1136 randomly selected children (548 boys and 588 girls) aged 9-13 years in urban (Pretoria Central) South Africa. Body mass, stature, skinfolds (subscapular and triceps) were measured. Data were analysed using descriptive statistics (means and standard deviations). Differences in the mean body fat percentage were examined for boys and girls according to their age group/race, using independent t-test samples. Girls had a significantly (p = 0.001) higher percentage body fat (22.7 ± 5.7%, 95% CI = 22.3, 23.2) compared to boys (16.1 ± 7.7%, 95% CI = 15.5, 16.8). Percentage body fat fluctuated with age in both boys and girls. Additionally, girls had significantly (p = 0.001) higher percentage body fat measurements at all ages compared to boys. Viewed racially, black children (20.1 ± 7.5) were significantly (p = 0.010) fatter than white children (19.0 ± 7.4) with a mean difference of 4.0. Black children were fatter than white children at ages 9, 10, 12 and 13 years, with a significant difference (p = 0.009) observed at age 12 years. There was a considerably higher level of excessive percentage body fat among school children in Central Pretoria, South Africa, with girls having significantly higher percentage body fat compared to boys. Racially, black children were fatter than white children. The excessive percentage body fat observed among the children in this study has implications for their health and fitness. Therefore, an intervention programme must be instituted in schools to prevent and control possible excessive percentage body fat in this age group.

Association between infant nutrition and anthropometry, and pre-pubertal body composition in urban South African children – ERRATUM

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Association between infant nutrition and anthropometry, and pre-pubertal body composition in urban South African children.

Early life nutrition and growth are related to subsequent obesity risk in high-income countries. We investigated the association between nutrition and growth during infancy, and body composition at 10 years of age in 140 children selected from the Bone Health sub-study of the Birth-to-Twenty cohort from Soweto, Johannesburg, South Africa. Infant feeding and dietary data were collected during the first 12 months, and weight and height were measured at 1 and 2 years of age. At 10 years, anthropometry and dual-energy X-ray absorptiometry (DXA)-derived body composition were measured. Regression models were used to determine associations between independent and dependent variables at the 1% level of significance. A one z-score increase in birth weight was associated with a 1051 g increase in lean mass and a 0.22 increase in body mass index (BMI) z-score at the age of 10 years. After adjusting for confounders, stunting at age 1 year was associated with lower fat mass only at 10 years of age while at age 2 years, it was associated with lower lean mass only. Being underweight at one year of age was significantly associated with lower lean mass only. Weight-for-age (WAZ) change in the second year of infancy was a predictor of fat mass and BMI only. Body fatness at 10 years of age was positively associated with infant WAZ change rather than height-for-age change. There were no significant associations between infant dietary patterns, wasting and being underweight at age 2 years and pre-pubertal body composition. Further studies are needed to assess whether these associations continue during adolescence as pubertal development may be an important modifier of these associations.

Linguistic liminality in the early years of school: Urban South African children ‘betwixt and between’1 languages of learning

This article is about an investigation into the English spoken language competence of 144 first graders in two urban (‘township’) schools in the Gauteng Province of South Africa. The study was conducted from an anthropological and a cognitive developmental perspective. In one school isiZulu and Sesotho are used mainly as medium of instruction, while in the other school the language of teaching and learning is English. The inquiry is part of longitudinal panel research in which children’s overall development and school progress over four years is documented by way of growth modelling. This initial assessment of the children’s basic interpersonal communication skills in English found, not unexpectedly, that the children in the first mentioned school know English mostly to the extent of the naming of objects, while the children in the other school are able to use morpho-syntactically more complex language. These findings may shed some light on the phenomenon of school culture liminality in its interplay with linguistic liminality, considering that children’s basic English may scaffold their academic English.

Economic burden of acute lower respiratory tract infection in South African children

Background: Acute lower respiratory tract infections (ALRTI) are a leading cause of childhood mortality, but there are few data on disease costs in developing countries.Objectives: This study’s purpose was to analyse ALRTI’s costs-of-illness and economic burden in urban South African children.Methods: ALRTI costs-of-illness (expressed in US$ 2010) at a tertiary hospital were measured using a micro-costing approach nested within a clinical trial. Demographic, epidemiological and data on use of health resources were integrated with costs-of-illness to estimate the economic burden of ALRTI in urban South African children aged <5 years.Results: 745 children experiencing 858 ALRTI episodes were studied. 338 (39·4%), 513 (59·8%) and 7 (0·8%) episodes were managed in short-stay, paediatric ward and intensive care settings, respectively. Mean lengths of stay in short-stay, paediatric ward and intensive care (ICU) were 1·4, 8·1 and 14·4 days, respectively. The societal costs-of-illness per ALRTI episode managed in short-stay and paediatric ward settings, respectively, were US$266 (95% CI 245–286) and 1287 (95% CI 1174–1401) in HIV-infected patients, and US$257 (95% CI 247–267) and 1032 (95% CI 931–1133) in HIV-uninfected patients. Family costs were not collected in ICUs. ICU direct medical costs were US$5968 (95% CI 4025–8056) in HIV-uninfected patients and US$7849 in one HIV-infected patient. Under-5 children experienced an estimated 424,220 episodes annually of ALRTI. ALRTI treatment cost the public health system an estimated US$28,975,000 while an additional US$539,000 of costs were borne by families.Conclusion: ALRTIs in children <5 years impose a heavy economic burden on families and the South African public health-care system.

Heterogeneity of fracture pathogenesis in urban South African children: The birth to twenty cohort

South African black children fracture less than white children. Differences in bone mass, body composition, and physical activity may be contributing risk factors. This study aimed to investigate the association between fracture prevalence, bone mass, and physical activity in South African children. Using the Bone Health cohort of the Birth to Twenty longitudinal study, we retrospectively obtained information of lifetime fractures until age 15 years in 533 subjects. Whole-body bone mineral content (BMC), bone area (BA), fat mass (FM), and lean mass (LM) (measured by dual-energy X-ray absorptiometry [DXA]), anthropometric data, physical activity scores, and skeletal maturity were obtained at ages 10 and 15 years. Nonfracturing black females were used as the control group and comparisons were made between those who did and did not fracture within the same sex and ethnic groups. Of the 533 subjects, 130 (24%) reported a fracture (black, 15%; white, 41.5%; p < 0.001). White males who fractured were significantly taller (10 years, p < 0.01), more physically active (15 years, p < 0.05) and had higher LM (10 years, p = 0.01; 15 years, p < 0.001), whereas white females who fractured were fatter (10 and 15 years, p = 0.05 and p < 0.05, respectively), than their nonfracturing peers. White males who fractured had greater BA and BMC at all sites at 10 and 15 years compared to their nonfracturing peers after adjusting for differences in height and weight; BA and BMC were similar in each of the other sex and ethnic groups. No anthropometric or bone mass differences were found between black children with and without fractures. The factor associated with fractures in white males appears to be participation in sports activities, while in white females obesity appears to play a role. No contributing factors in black males and females were found, and needs further elucidation.