Explaining Within-vs Between-Population Variation in Child Anthropometry and Hemoglobin Measures in India: A Multilevel Analysis of the National Family Health Survey 2015–2016

The complex etiology of child growth failure and anemia—commonly used
indicators of child undernutrition—involving proximate and distal risk factors
at multiple levels is generally recognized. However, their independent and
joint effects are often assessed with no clear conceptualization of inferential
targets.We utilized hierarchical linear modeling and a nationally representative
sample of 139,116 children aged 6–59 months from India (2015–2016) to
estimate the extent to which a comprehensive set of 27 covariates explained
the within- and between-population variation in height-for-age, weightfor-
age, weight-for-height, and hemoglobin level.Most of the variation in
child anthropometry and hemoglobin measures was attributable to withinpopulation
differences (80–85%), whereas between-population differences
(including communities, districts, and states) accounted for only 15–20%.
The proximate and distal covariates explained 0.2–7.5% of within-population
variation and 2.1–34.0% of between-population variation, depending on
the indicator of interest. Substantial heterogeneity was observed in the
magnitude of within-population variation, and the fraction explained, in
child anthropometry and hemoglobin measures across the 36 states/union
territories of India.Policies and interventions aimed at reducing betweenpopulation
inequalities in child undernutrition may require a different set of
components than those concerned with within-population inequalities. Both
are needed to promote the health of the general population, as well as that
of high-risk children.