Growth and nutritional status of rural South African children 3-10 years old: The Ellisras growth study

This study presents cross-sectional data from an ongoing mixed-longitudinal study of growth of rural children from Ellisras, South Africa. The physical growth and nutritional status of 1,335 children (684 boys, 651 girls), 3-10 years of age, was determined using standard anthropometric techniques. Weight-for-age, height-for-age, and weight-for-height were expressed as Z-scores of the NHANES I and II or NCHS reference sample. A Z-score of less than -2 was used as the cut-off point to determine the prevalence of stunting and wasting. Mean heights increased parallel to the 50(th) centile up to 6 years of age, thereafter both sexes diverged from the NHANES reference by approximately 0.5 cm per year. Mean weights followed a more consistent pattern from 3-7 years for both sexes, which was parallel to just below the 10(th) centile, but diverged between 8 and 10 years of age. Z-scores of weight-for-height in both sexes varied between -1 to -2 throughout the age range and BMI values were lower than the 5(th) centile of NHANES, indicating a significant amount of wasting within the sample. The sample exhibited a high prevalence of stunting, rising from less than 10% at 7 years to more than 30% by 10 years of age. Increments of the mean heights and weights indicate that the effects of stress may be a gradually accumulating process and that the growth increments of these children became increasingly poor in contrast to those of the reference sample. Since stunting in childhood is permanent, it may lead to a loss of physical work capacity in adulthood. Therefore, further investigation of the cause of poor growth among these rural children is imperative. Am. J. Hum. Biol. 12:42-49, 2000. Copyright 2000 Wiley-Liss, Inc.

An inverse relation between blood pressure and birth weight among 5 year old children from Soweto, South Africa

STUDY OBJECTIVE

To examine the relation between birth weight and blood pressure at 5 years in a cohort of South African children.

DESIGN

Prospective cohort study.

PARTICIPANTS

849 five year old children.

SETTING

Soweto, a sprawling urban area close to Johannesburg, South Africa, which was a designated residential area for people classified as "black" under apartheid legislation.

MAIN RESULTS

Systolic blood pressure at 5 years was inversely related to birthweight (r = -0.05, p = 0.0007), independent of current weight, height, gestational age, maternal age or socioeconomic status at 5 years. There was no relation between birth weight and diastolic blood pressure. After adjusting for current weight and height, there was a mean decline in systolic blood pressure of 3.4 mm Hg (95% confidence intervals 1.4, 5.3 mm Hg) for every 1000 g increase in birth weight.

CONCLUSIONS

These data from a disadvantaged urbanised community in Southern Africa extend the reported observations of an inverse relation between birth weight and systolic blood pressure. The study adds to the evidence that influences in fetal life and early childhood influence systolic blood pressure. Further research is required to assess whether efforts to reduce the incidence of low birthweight babies will attenuate the prevalence of hypertension in future generations.

Association between poor glucose tolerance and rapid post natal weight gain in seven-year-old children

A number of studies have shown that glucose tolerance falls with decreasing birth weight and that people with low birth weight and high body mass index (BMI) as adults are those at greatest risk of developing Type II (non-insulin-dependent) diabetes mellitus. No such studies have been carried out in African populations. Therefore we investigated the relation between glucose tolerance and birth weight in a group of 7-year-old black South Africans for whom longitudinal anthropometric data were available. Oral glucose tolerance tests (OGTTs) were carried out on 152 subjects and inverse correlations were found between birth weight and the total amount of insulin secreted during the first 30 min (r = -0.19, p = 0.04) and last 90 min (r = -0.19, p = 0.04) of the oral glucose tolerance test and also between birth weight and the 30 min glucose concentrations (r = -0.20, p = 0.02). Children born with low birth weights but who had high weights at 7 years had higher insulin concentrations and indices of obesity compared with those with low birth weights and low weights at 7 years. There were also positive correlations between weight velocity and BMI (r = 0.24, p = 0.02) and weight velocity and insulin resistance (r = 0.18, p = 0.04) as measured using homeostasis model assessment (HOMA). Thus, low birth weight in conjunction with rapid childhood gains in weight especially as subcutaneous fat, produces poor glucose tolerance in 7-year-old children and can make them susceptible to the development of Type II diabetes later in life.

Growth in height and weight of South African urban infants from birth to five years: The Birth to Ten Study

The Birth To Ten (BTT) birth cohort study was designed to investigate the health and growth of children living in the Soweto-Johannesburg Metropole, South Africa. During 1990-1991, 4034 singleton births, from a total birth population of 5449 that occurred between 23 April and 8 June, 1990, were enrolled into the study. Anthropometric, socioeconomic, health, nutritional, and demographic data were collected at birth and at 3, 6, 12, 24, 48, and 60 months. Socioeconomic data relating to household commodities, maternal education, and paternal occupation were combined to create socioeconomic status (SES) groups for comparative purposes. Mean birth weights were less than American norms and demonstrated significant differences between the sexes. The percentage of low birth weight children of normal gestational age (7.1%) was similar to that of developed countries. Growth in weight exceeded that of the National Center for Health Statistics (NCHS) reference during the first 6 months and then fell to -0.43 Z-scores by 4 years. Height growth was consistently less than the NCHS reference and the prevalence of stunting and wasting increased to 22.4% and 6.8%, respectively, by 2 years. Catch-up occurred between 4 and 5 years resulting in a reduction in the prevalence of stunting and wasting to 5.4% and 0.8%, respectively, at 5 years. SES differences were apparent throughout the time period but only reached significance in height and weight after 4 years of age. Am. J. Hum. Biol. 10:495-504, 1998. © 1998 Wiley-Liss, Inc.

Sex differences in the prevalence of obesity in rural African adolescents

OBJECTIVE

To investigate the prevalence and gender differences in obesity in rural African adolescents.

DESIGN

Cross-sectional analysis of a mixed-longitudinal study.

SUBJECTS

Four hundred and forty-seven rural African adolescents (190 females; 257 males) aged 7.0-18.9 y.

MEASUREMENTS

Anthropometric measurements of height, weight, and skinfolds at the bicep (BCP), tricep (TRCP), subscapular (SSCP) and suprailiac (SPIL) sites and derived ratios of fat distribution including trunk:limb ratios (SSTB = (SSCP + SPIL)/(TRCP + BCP) and ST = SSCP/TRCP), and the upper:lower truncal ratio (TRUNK = SSCP/SPIL). Obesity was defined as (1) a BMI greater than the NHANES III 85% centile or (2) the sum of TRCP and SSCP skinfolds greater than the NHANES III 85% centile.

RESULTS

Skinfold measures were significantly greater in females throughout the age range but remarkably greater divergence was apparent after mean menarcheal age of 14.03 y (s.d. = 1.25). Centralization of body fat was consistently greater in males but only significantly so after 14 y of age for the ST ratio. Obesity, defined by BMI or sum of skinfolds, was greatest in females following menarche reaching a maximum of 16.7% by BMI and 11.1% by sum of skinfolds, and almost non-existent in males.

CONCLUSIONS

Increased prevalence of obesity in African females did not occur throughout adolescence but was linked to the timing of menarche. Increased fatness and obesity appears to be a post-menarcheal phenomenon probably caused by the hormonal changes leading to and following first menstruation.

The organisation of a national survey for evaluating child psychomotor development in Argentina

A total of 211 selected paediatricians were invited to participate in a national survey designed to evaluate the age of attainment of developmental milestones in children aged 0-5 years. Following a pilot study and a cascade training design, 61.1% of the paediatricians successfully completed the data collection on 139 developmental items. In the pilot study, there were more missing (not performed) items in children over one year of age, thus confirming the impression that paediatricians are more familiar with evaluating development in infants. However, in the age range 1-5 years, there were significantly fewer missing items in the gross motor area than in the other areas. Following a training programme and data editing and cleaning, a final sample of 3573 healthy, normal children was obtained. The impact of the training process was significant, in the sense that 3.5% of the items in children older than one year were not performed by the paediatricians before training, but this percentage was reduced to 1.9% after training (P < 0.01). The sample formed 0.11% of the national population less than 6 years of age and included a sex ratio of 1.01 compared with a national ratio of 1.02. There were no significant differences in the geographical distribution of the sample in comparison with that of the national population. The social composition, assessed by maternal education level, was biased towards a better education level than the national population. Mean Z-scores for height and weight were not significantly different from zero, when calculated on the basis of the national growth standards. In addition to successfully obtaining a representative sample for the analysis of the age of attainment of developmental milestones in Argentinian children, the survey also accomplished an educational objective in the training of paediatricians in developmental paediatrics.

Menarcheal age in two generations of South African Indians

Intergenerational and socioeconomic effects on menarcheal age were investigated in a sample of 146 mother-daughter pairs of South African Indians living in the urban area of Lenasia, Gauteng Province. Information on menarcheal age, socioeconomic status, and educational attainment of both parents was obtained by questionnaire. Data on menarcheal age of daughters were analysed by probit analysis and descriptive statistics. Mean maternal menarcheal age was 13.20 years (SD = 1.57) and was significantly greater than the menarcheal age of the postmenarcheal daughters at 12.52 years (SD = 1.25) and of mean menarcheal age analysed by probits of 12.40 years (SD = 1.18). Mother-daughter menarcheal ages were significantly correlated (r = 0.23; p < 0.035). This association was confounded by the significant association of maternal menarcheal age to the age at which mothers recalled that event (r = 0.32; p < 0.003). Partial correlations demonstrated that the mother-daughter correlation reduced to a non-significant 0.16 (p < 0.14) after maternal age at recall had been controlled. No significant associations were found between socioeconomic variables and menarcheal age except for family size, in which girls with more than three siblings had significantly later menarcheal ages than girls with three siblings. Secular trends for reduced menarcheal ages were evident in both the intergenerational data (0.24 years/decade) and in comparison to the data of Kark (1953) from four decades ago (0.27 years/decade).

Need for overnight respite for primary caregivers of hospice clients

A major reason for admission of community hospice clients to the hospital is exhaustion of the primary caregiver. One way to prevent the problem of caregiver exhaustion may be the use of trained laypersons who remain overnight with the ill person, thereby providing respite that allows the caregiver to sleep. A survey was conducted to assess primary caregivers' appraisal of the need for overnight respite and their willingness to receive this support from trained laypersons. Thirty-seven primary caregivers, who used the services of a community hospice, were interviewed to determine primary caregivers' appraisals of problems, resources, and needs. Ten (27%) primary caregivers reported usually receiving 0 to 4 of sleep per night and 27 (73%) reported receiving > 4 h. Sleep time was described by the majority as insufficient, but insufficient, sleep was statistically not a main reason for hospital admission. Findings suggested that those in the 0- to 4-h category were more vulnerable to exhaustion. Seventy percent of respondents indicated that they would use the services of a trained layperson for overnight respite and an additional 6% indicated that they would under certain conditions.

Enrolment into Birth to Ten (BTT): population and sample characteristics

The population under study in the South African longitudinal study of urban children and their families, 'Birth to Ten' (BTT), comprised all births during a 7-week period from April to June 1990 in Soweto-Johannesburg. Specification of the population base for the cohort was hampered by a number of flaws in the notification and record-keeping systems of the local authorities. As far as could be ascertained, 5460 singleton births occurred during this time to women who gave a permanent address within the defined region. Enrolment into BTT took place over the first 15 months of the study and covered the antenatal, delivery, 6-month and 1-year periods. By the end of this time, and despite a major health service strike during the delivery phase, 74% of all births (4029 cases) had been enrolled into the study. There were marked variations in levels of enrolment, however, by population group membership, residential area and place of delivery. In general, there was substantial under-enrolment of largely middle-class white women and their babies. Initial non-enrolment of specific segments of the population and attrition of the enrolled sample up to the end of the first year are discussed in the context of racial and social differentiation in South Africa.

Longitudinal analysis of adolescent growth in height, fatness, and fat patterning in rural South African black children

Adolescent growth in height, fatness, and fat patterning was investigated in a sample of 79 rural South African black children studied longitudinally from 6-18 years. Data were analyzed relative to peak height velocity (PHV) to identify the phenomenon of "compensatory" growth in height during adolescence and to describe changes in fatness and fat patterning. Compensatory growth following PHV was clearly observed relative to NHANES data for African-Americans in that Z-scores for height at the start of the adolescent growth spurt were greater than those at the end of the spurt. Statistically significant differences in fatness and centralization between males and females did not occur until about 2 years after PHV was attained. Centralization of fat occurred in both sexes but more so in males. The lack of centralization in females was due to relatively greater triceps skinfold velocities. The rapid gain in post-PHV fatness in females may represent a physiological adaptation to an energetically sub-optimal environment, buffering the energetic costs of reproduction.

Secondary sexual development in rural and urban South African black children

The timing and duration of secondary sexual development in two samples of rural and urban South African black children were investigated using the Tanner staging techniques and compared to similar data from Switzerland and England. In general rural black children were consistently delayed in the age at which they entered the events of puberty, and took longer to pass through each of the stages. Urban black children, from good socioeconomic backgrounds, were advanced in relation to their rural peers and slightly ahead of the European samples. There were no significant differences in the sequence of events. Estimates of testicular volume on the well-off urban boys demonstrated that they exhibited similar volumes to European boys at similar ages. It is suggested that the British clinical longitudinal growth standards could be effectively used to sensitively monitor the growth and maturation of black urban children from good socioeconomic backgrounds.

The growth of South African rural black children

The growth status of two samples of South African rural black children, from Ubombo, KwaZulu, and Vaalwater, northern Transvaal, was compared with that of samples of American black children and three other rural sub-Saharan groups. All the sub-Saharan black children were shorter, lighter and had less subcutaneous fat than the American children. Their growth curves demonstrated the well-recognised pattern of deviation from American means before adolescence so that, by the start of adolescence, approximately 50% of the children were below the 10th centile of American norms. Adolescence in all groups is delayed and the magnitude of peak velocity reduced. The adolescent growth spurt appears, however, to be extended along the time base so that pre- and post-peak velocities are raised; this leads to apparent catch-up growth in the late teenage years. While the Vaalwater sample demonstrated growth patterns very similar to those of other rural sub-Saharan black groups, the Ubombo children were consistently taller and heavier than all the others. These data are discussed in relation to the need for national norms that reflect the growth status of black South African children.

Assessment of growth and maturation during adolescence

Clinical techniques currently used to assess adolescent growth and maturation are critically assessed with regard to anthropometric dimensions, measurement reliability, maturity indicators, and growth standards. While anthropometric measurements are virtually standardized throughout the world, a choice of techniques is available for the assessment of skeletal maturity, dental maturity and secondary sexual development. In addition, a variety of charts of international and national reference data are available for the comparison of individuals and groups. These assessment and comparison techniques are contrasted and compared to arrive at a scientifically appropriate set of recommendations for the clinical assessment of growth and maturity during adolescence.

Urban-rural differences in the growth of South African black children

Urbanization is a major migratory process characteristic of developing countries. The majority of comparisons of the growth of urban and rural children from developed countries reflect greater heights and weights, and by implication health, of urban children. Urban-rural comparisons of South African black children are few in number and have concentrated on 'average' children, thereby omitting the factor of socioeconomic status. The present study compares two groups of urban children of high (n = 307) and average (n = 867) socioeconomic status and two groups of rural children. The rural children came from farm labourer's families (n = 392) and traditional subsistence farming environments (n = 420). The children ranged in age from 5 to 19 years. In general the well-off urban children were consistently, but not significantly, larger than all other groups and 'average' urban children were consistently and at times significantly smaller and lighter. The growth of the two rural groups fell between these extremes but were also consistently different in that the children of farm labourers were significantly lighter at all ages than children living in a traditional subsistence economy. It is concluded that the average urban environment in South Africa is not conducive to improved growth and health unless it is accompanied by an improved socioeconomic status.