The relationship between wasting and stunting, policy,programming and research implications, 2014. Emergency Nutrition Network; USAID.
Authors: Tanya Khara & Carmel Dolan
Burden
1. Both wasting and stunting often coexist in the same child though the extent to which this happens is largely unreported (despite the fact that the data required is available in all standard nutrition surveys). This condition may have particular causal pathways and effects which are not yet fully understood.
2. Seasonality has a marked impact on both wasting and stunting prevalence (the magnitude of the effect is, in general, greater for wasting).
3. Rates of gain in weight and height often take place at different times of year and seem to be related over time in a consistent way, with height faltering peaking 2-3 months after weight loss/wasting levels have peaked.
4. Measuring the association between wasting and stunting at population level is challenged by the use of prevalence data. Wasting has a relatively shorter duration than stunting and is also highly variable seasonally. Therefore, the relatively large proportion of incident wasting cases occurring over time will be missed and, depending on the timing of the survey, seasonal peaks may also be missed. Combined, this may lead to underestimates of yearly burden of wasting compared to stunting, the burden of which is better captured by cross sectional surveys.
Shared risk factors
5. Wasting and stunting have many common risk factors as illustrated by the UNICEF conceptual framework and indicated by the literature.
6. There is good evidence that in-utero conditions and foetal growth contribute significantly to stunting at birth and during infancy; there is emerging evidence of contributions to wasting. Evidence suggests that height trajectory during childhood is related to initial height-for-age at birth (and by association foetal growth) and to some extent, to initial weight-for-height at birth.
7. Infectious diseases in early childhood make an important contribution to both wasting and stunting. Diarrhoea, in particular, is associated with short-term weight loss. Evidence is less strong for the long-term effect of diarrhoea on linear growth.
8. There is evidence to suggest that inflammation and gut health may also play an important role in stunting (either via the effects of chronic inflammation, malabsorption and/or appetite effects) and there is a need to investigate effects on wasting also.
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