Growth patterns among indigenous Qom children of the Argentine Gran Chaco

This study describes and compares the growth strategies of rural (Western) and peri-urban (Eastern) Qom indigenous children from Argentina.

Height and weight were cross-sectionally assessed in Western (n = 263) and Eastern Qom (n = 512) individuals aged 0-18.9 years. Height-for-age (HAZ), weight-for-age (WAZ), and BMI-for-age (BMIZ) z-scores were calculated with an LMS software. Results were organized into four age categories: infancy, childhood, juvenility, and adolescence. Between-group comparisons of HAZ, WAZ, and BMIZ were carried out by age and sex categories and compared with Student's t or Mann Whitney tests. Nutritional status was classified based on BMIZ following WHO recommendations and was compared with x2 tests.

In both groups, height and weight followed the typical human growth curve. Mean HAZ scores in both groups were within two standard deviations from the international reference, and increased from infancy to juvenility. WAZ and BMIZ scores were high during infancy and showed a general declining trend with age. Overall, Western Qom had higher HAZ scores. WAZ and BMIZ score comparisons showed only a handful of statistically significant differences, which, along with the analysis of BMI categories, indicated an association between peri-urban environments and a higher prevalence of overweight and obese individuals (P < 0.01).

Among the Qom, low HAZ and high WAZ scores during the early years of development allow for the attainment of a relatively high adult stature. Their adaptive life-history strategy seems to be to divert energy toward body mass during early development, and catch-up with linear growth at a later stage of development. Am. J. Hum. Biol. 28:895-904, 2016. © 2016Wiley Periodicals, Inc.