Sibling correlations for growth status in schoolchildren from a rural community in Oaxaca, Mexico

Sibling similarities in several anthropometric dimensions were examined in schoolchildren from a rural, agrarian Zapotec community in the Valley of Oaxaca in southern Mexico. The sample consisted of 44 brother, 44 sister, and 110 unlike-sex sibling pairs. Anthropometric dimensions included weight, height, limb circumferences, triceps skinfold, skeletal lengths, and craniofacial, trunk, and extremity breadths. Environmental effects were controlled using data from a household survey, and were summarized in composite variables. Environmental covariance was suggested in partial correlations of the sibling z-scores. The base 10 log of environmental data and sibling z-scores produced slightly different results. Partial correlations of the log-transformed data resulted in a slight overall decrease in sibling correlations for all pairings. This suggests a genetic-environment interaction, and may offer an explanation for the generally higher sibling correlations observed in non-European populations than in European-derived ones.