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.

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.

Body fat patterning in rural South African black children.

Growth status, body fatness, and fat patterning were investigated in two cross-sectional samples of rural South African Black children 6-19 years of age. The results were compared to data for American Blacks who were part of the NHANES survey. The two South African samples differed consistently, although rarely significantly, but both were smaller, lighter, and less fat than American Blacks. Analyses of triceps, biceps, subscapular, and suprailiac skinfolds demonstrated that all three samples had similar fat patterning when analysed either by investigating the Centripetal Fat Ratio or through an analysis of principal components. Following correction for general fatness, and in common with other studies of fat patterning, the first component related to central-peripheral patterning, the second to a ventral-dorsal patterning, and the third to upper-lower body patterning. These three components accounted for 99.4% of the total variance. It is suggested that central-peripheral fat patterning is a species characteristic but that other patterns are individual characteristics. Analysis of principal components within childhood, pre-adolescent and adolescent age groups suggested that prior to adolescence a negative relationship exists between absolute level of fatness and centralization such that thinner, less fat, children are more centralized. During adolescence, however, there is no relationship between level of fatness and centralization. © 1992 Wiley-Liss, Inc.

Age at menarche and an analysis of secular trends in menarcheal age of South African urban and rural black females.

Age at menarche was estimated using status quo techniques on a sample of 230 rural South African females aged 11 to 17 years. Mean age of menarche was 14.03 years (SD = 1.25 years). Compared with contemporary rural and well-off urban samples, these females experienced menarche 0.6 years earlier than did the rural sample and 0.8 years later than the well-off urban group. Data from 11 previously reported studies of menarcheal age in urban and rural girls were analyzed with these data to determine the existence and magnitude of secular trends and whether rates differed between urban and rural environments. Regression analysis demonstrated a clear secular trend in both urban and rural females since 1943. Menarcheal age decreased at a rate of 0.34, 0.73, and 0.46 years per decade for rural, urban, and combined groups, respectively. The decline in menarcheal age over the last 40 years is thought to be due to improving socioeconomic conditions, but differences between urban and rural groups remain. Within rural groups there appears to be considerable variation in menarcheal age.