Anthropometric heritability and child growth in a Caribbean village: A quantitative genetic analysis of longitudinal height, weight, and body mass index in Bwa Mawego, Dominica.

Abstract

Body size and composition vary widely among individuals and populations, and long-term research in diverse contexts informs our understanding of genetic, cultural, and environmental impacts on this variation. We analyze longitudinal measures of height, weight, and body mass index (BMI) from a Caribbean village, estimating the extent to which these anthropometrics are shaped by genetic variance in a small-scale population of mixed ancestry. Longitudinal data from a traditionally horticultural village in Dominica document height and weight in a non-Western population that is transitioning to increasingly Westernized lifestyles, and an 11-generation pedigree enables us to estimate the proportions of phenotypic variation in height, weight, and BMI attributed to genetic variation. We assess within-individual variation across growth curves as well as heritabilities of these traits for 260 individuals using Bayesian variance component estimation. Age, sex, and secular trends account for the majority of anthropometric variation in these longitudinal data. Independent of age, sex, and secular trends, our analyses show high repeatabilities for the remaining variation in height, weight, and BMI growth curves (>0.75), and moderate heritabilities (h2height = 0.68, h2weight = 0.64, h2BMI = 0.49) reveal clear genetic signals that account for large proportions of the variation in body size observed between families. Secular trends show increases of 6.5% in height and 16.0% in weight from 1997 to 2017. This horticultural Caribbean population has transitioned to include more Westernized foods and technologies over the decades captured in this analysis. BMI varies widely between individuals and is significantly shaped by genetic variation, warranting future exploration with other physiological correlates and associated genetic variants.