The 89th Annual Meeting of the American Association of Physical Anthropologists (2020)


Allometric correlates of infant mass growth rate variation

STEVEN R. LEIGH1, DANIEL J. NAUMENKO1,2, NABEEL AFFARA3, DAVID B. DUNGER4, KEN K. ONG4,5, ANDREW M. PRENTICE6, SOPHIE E. MOORE7 and ROBIN M. BERNSTEIN1,2.

1Department of Anthropology, University of Colorado, 2Institute of Behavioral Science, University of Colorado Boulder, University of Colorado, 3Department of Pathology, University of Cambridge, 4Department of Paediatrics, University of Cambridge School of Clinical Medicine, 5MRC Epidemiology Unit, University of Cambridge School of Clinical Medicine, 6MRC Unit, The Gambia at LSHTM, Banjul, The Gambia, 7Department of Women and Children's Health, King's College London

April 16, 2020 , Platinum Ballroom Add to calendar

Perturbations of growth and development may have serious, persistent consequences. We investigate weight growth irregularities to determine the consequences of possible perturbations on morphological integration and allometric relations during infancy. A primary hypothesis is that irregular weight growth (weight vs. age curve) is associated with decreased morphological integration and allometric shifts in other dimensions.

Repeated somatometric measures from a mixed-sex sample of 50 individual Gambian children from the HERO-G study (Hormonal and Epigenetic Regulators Of Growth), are analyzed to explore allometric correlates of weight growth irregularity. We calibrate irregularities qualitatively. Specifically, we distinguish individuals showing relatively smooth weight-for-age trajectories (“regular”) from those showing clear and repeated weight growth reductions and rebounds (“irregular”). Allometries are described by bivariate analyses of all variable pairs (weight, length, head circumference, and knee-heel length) measuring correlations and allometric coefficients. We test for mean differences in correlations and coefficients between groups.

Individuals categorically described as experiencing irregular growth generally show statistically significantly lower correlations for all 6 variable pairs, with the possible exception of length and weight vs. head circumference (both approach significance at p=.05). Allometric coefficients are consistent, with no major group differences in coefficients.

These preliminary results suggest that irregularities in weight growth are associated with reduced morphological integration during ontogeny. This may pose challenges for individuals with respect to catch-up growth, and could have biomechanical implications. However, allometric slopes appear to be robust to such irregularities, suggesting that general allometric relations between dimensions are preserved through disruptions.

Funded by the Bill and Melinda Gates Foundation (OPP1066932).