Background: Stunting-or impaired child growth due to undernutrition-has multiple negative health effects, making it a top global health priority. The current benchmark for classifying stunting assumes a universal model of growth with height-for-age z-score (HAZ) cutoffs set by the World Health Organization. However, this model may hide hotspots of stunting if populations differ in HAZ in ways that are independent of undernutrition. We examine how universal cutoffs can underestimate stunting in specific regions around the world. Methods: Using a non-linear multi-level model , we decompose variation in height-for-age z-scores (HAZ) from 1, 430,986 children across 63 countries into two components: 1) "accrued HAZ" shaped by environmental inputs-undernutrition, infectious disease, inadequate sanitation,  and 2) a country-specific "basal HAZ" independent of such inputs. We validate these components by assessing their associations with key indicators of undernutrition. We then re-estimate stuntingprevalence with population-sensitive cutoffs based on the estimates of these two components . Results: Basal HAZ differs reliably across countries (range of 1.6 SD) and is independent of measures of undernutrition . By contrast, accrued HAZ captures stunting as impaired growth due to deprivation . Population-sensitive estimates suggest that universal cutoffs can miss 1 in 5 children in specific world regions, where children have greater basal heights. Conclusion : Current universal cutoffs may miss stunting in populations with taller basal HAZ. As stunting is a high priority in global health, standards that are sensitive to population variation in healthy growth should improve efforts to target those most vulnerable to childhood undernutrition .
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 paper partitions variation in height-for-age that is specifically associated with deprivation and health outcomes to provide a basis for cross-population comparisons. Materials Methods: Using a multi-level model with a sigmoid relationship of resources and growth, we partition variation in height-for-age z-scores (HAZ) from 1, 522,564 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 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. Ranking populations by accrued HAZ suggest that populations in West Africa and the Caribbean suffer much greater levels of stunting than suggested 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 .
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Background: Stunting-or impaired child growth due to undernutrition-has multiple negative health effects, making it a top global health priority. The current benchmark for classifying stunting assumes
Objectives: Current standards for comparing stunting across human populations assume
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growth with height-for-age z-score (HAZ) cutoffs set by the World Health Organization. However, this model may hide hotspots of stunting if populations differ in HAZ in ways
child growth. Such comparisons ignore population differences
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undernutrition. We examine how universal cutoffs can underestimate stunting in specific regions around the world.
deprivation and health outcomes. This paper partitions variation in height-for-age that is specifically associated with deprivation and health outcomes to provide a basis for cross-population comparisons. Materials
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non-linear
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, we decompose
with a sigmoid relationship of resources and growth, we partition
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430,986 children across 63
522,564 children across 70
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inputs-undernutrition,
inputs (e.g., undernutrition,
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poverty),
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by assessing their associations with key indicators of undernutrition. We then re-estimate stuntingprevalence with population-sensitive cutoffs based on the estimates of these two components
against population-level infant mortality rates, and assess how these basal differences may affect cross-population comparisons of stunting
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1.6
1.5
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undernutrition
infant mortality
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. Population-sensitive estimates suggest that universal cutoffs can miss 1 in 5 children in specific world regions, where children have greater basal heights. Conclusion
and is more closely associated with infant mortality than observed HAZ. Ranking populations by accrued HAZ suggest that populations in West Africa and the Caribbean suffer much greater levels of stunting than suggested by observed HAZ. Discussion
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cutoffs may miss
standards may dramatically underestimate
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As stunting is a high priority in global health, standards that are sensitive to population variation in healthy growth should improve efforts to target those most vulnerable to childhood undernutrition
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