Sex differences in anthropometric variability among South African rural school children

Abstract

Studies have reported no sex differences in variability of anthropometric characteristics, except in skinfolds with males more varied than females. Whether this is true of South African rural children is not known. The purpose of this study was to investigate the potential sexual anthropometric variability and verify its presence in rural South African children. Data on 263 female and 190 male participants from the Physical Growth, Health, Nutritional and Physical Fitness Status of Rural South African children: Tshannda Longitudinal Study, were used to demonstrate the similarity or otherwise of variability of 42 anthropometric items across sexes and support the use of non-sex biased proportionality models. The anthropometric measurements recorded were body mass, stature, sitting height and arm span, as well as skinfolds, girths, lengths and breadths. Coefficient of variation of these measurements demonstrated similarity for each sex and for each item in all categories except skinfolds. The highest values are associated with skinfold thickness ranging from 43.3% (triceps) to 65.6% (abdominal) in males and for females from 43.1% (medial calf) to 73.2% (mid-axilla). Skinfolds coefficients of variation were greater in males than in females. The results do not show appreciable variations in lengths, breadths and girths. The results confirm the similarity or variability of anthropometric variables and support the use of non-sex biased proportionality models. Skinfold dispersion dimorphism seems to exist between males and females, with the females more variable than males. This phenomenon might be attributed to cultural factors influencing the extent of female variability by means of enhanced environmental homogeneity.

Keywords: Anthropometry, coefficients of variability, sex, rural South African children