Vitamin A supplementation among 9-59 month old children in India: geospatial perspectives and implications for targeted coverage

Abstract

Introduction: Vitamin A supplementation (VAS) is yet to reach all Indian children aged 9-59 months, despite guidelines for universal coverage. This study mapped geospatial patterns underlying VAS coverage across two policy-relevant administrative unit levels (states and districts) in India. The relationship between spatial distribution of VAS coverage and vitamin A deficiency (VAD) prevalence was also investigated.

Methods: The study draws on nationally representative cross-sectional data collected during National Family and Health Survey 4 (NFHS-4) and Comprehensive National Nutritional Survey (CNNS). VAS coverage was estimated using information obtained during NFHS-4 from mothers about whether their children (n=204 645) had received VAS within 6 months of the survey. VAD prevalence estimates were based on serum retinol measurements during CNNS in under-five children (n=9563). State-level and district-level choropleth maps of VAS coverage were constructed. Spatial patterns were probed using Moran's statistics, scatter plots and local indicators of spatial association (LISA). Relationship between VAS coverage (as an explanatory variable) and VAD prevalence was explored using spatial autoregressive models.

Results: VAS coverage in India (overall 60.5%) ranged from 29.5% (Nagaland) to 89.5% (Goa) across the various states/union territories. Among districts, it ranged from 12.8% (Longleng district, Nagaland) to 94.5% (Kolar district, Karnataka). The coverage exhibited positive spatial autocorrelation, more prominently at the district-level (univariate Moran's I=0.638, z-value=25.614, pseudo p value=0.001). LISA maps identified spatial clusters of high coverage and low coverage districts. No significant spatial association was observed between VAS coverage and VAD prevalence in the states during spatial error (R²=0.07, λ=0.30, p value=0.14) and spatial lag (R²=0.05, ρ=0.25, p value=0.23) regression.

Conclusion: Two out of every five eligible Indian children were not supplemented with vitamin A. The coverage was geographically heterogeneous with discernible spatial patterns. Their consequences on vitamin A status and associated health effects in the community deserve close monitoring.

Keywords: child health; epidemiology; nutrition; public health.

Figure 1

Choropleth maps showing coverage of vitamin A supplementation (VAS) among children aged 9–59 months in India, 2015–2016, across (A) states/union territories, and (B) districts. (Values within square brackets in the colour legends indicate the specified VAS coverage range, and values within round brackets indicate the number of states/union territories or districts belonging to that coverage range).

Figure 2

Global univariate Moran’s I statistic with scatter plot showing spatial autocorrelation underlying the coverage of vitamin A supplementation at (A) state-level, and (B) district-level.

Figure 3

Spatial patterns with district-level locational information of vitamin A supplementation coverage across India, 2015–2016, unravelled by local indicator of spatial association (LISA) analysis, illustrated through (A) LISA cluster map (default analysis), (B) LISA significance map (default analysis), (C) LISA cluster map (sensitivity analysis) and (D) LISA significance map (sensitivity analysis). (Values within round brackets in the colour legends indicate the number of districts belonging to the specified category in the map).

Figure 4

Relationship between prevalence of vitamin A deficiency and coverage of vitamin A supplementation across the states, examined by bivariate Moran’s I statistic with scatter plot.