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Disentangling basal and accrued height‐for‐age for cross‐population comparisons
Author(s) -
Hackman Joseph V.,
Hruschka Daniel J.
Publication year - 2020
Publication title -
american journal of physical anthropology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.146
H-Index - 119
eISSN - 1096-8644
pISSN - 0002-9483
DOI - 10.1002/ajpa.23990
Subject(s) - population , demography , poverty , malnutrition , developing country , child mortality , geography , environmental health , medicine , biology , ecology , economics , pathology , sociology , economic growth
Objectives Current standards for comparing stunting across human populations assume a universal model of child growth. Such comparisons ignore population differences that are independent of deprivation and health outcomes. This article partitions variation in height‐for‐age that is specifically associated with deprivation and health outcomes to provide a basis for cross‐population comparisons. Materials and Methods Using a multilevel model with a sigmoid relationship of resources and growth, we partition variation in height‐for‐age z ‐scores (HAZ) from 1.5 million children across 70 countries into two components: (1) “accrued HAZ” shaped by environmental inputs (e.g., undernutrition, infectious disease, inadequate sanitation, poverty) and (2) a country‐specific “basal HAZ” independent of such inputs. We validate these components against population‐level infant mortality rates and assess how these basal differences may affect cross‐population comparisons of stunting. Results Basal HAZ differs reliably across countries (range of approximately 1.5 SD) and is independent of measures of infant mortality. By contrast, accrued HAZ captures stunting as impaired growth due to deprivation and is more closely associated with infant mortality than observed HAZ. Assessing stunting prevalence by accrued HAZ suggest that populations in West Africa and Haiti suffer much greater levels of stunting than indicated by observed HAZ. Discussion Current universal standards may dramatically underestimate stunting in populations with taller basal HAZ. Relying on observed HAZ rather than accrued HAZ may also lead to inappropriate cross‐population comparisons, such as concluding that Haitian children enjoy better conditions for growth than do Indian or Guatemalan children.