|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.|
||Justin Rodgers, Rockli Kim, and S.V. Subramanian
||Journal of Epidemiology, Published online; DOI: 10.2188/jea.JE20190064
||Background: 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.
Methods: 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, weight-for-age, weight-for-height, and hemoglobin level.
Results: Most of the variation in child anthropometry and hemoglobin measures was attributable to within-population 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.
Conclusions: Policies and interventions aimed at reducing between-population 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 high-risk children.