The current state of evidence and thinking on wasting prevention
Summary of research1
ENN produced a report, through the MQSUN+ programme, that synthesises existing evidence and stakeholder opinion on what works to prevent wasting. This report is one output of a multi-phase scope of work, commissioned and funded by the UK Department for International Development (DFID) on “adopting a strategic, evidence-based approach to wasting prevention” and follows a briefing paper produced by ENN titled “The aetiology ofwasting”.2 The current report set out to answer the following questions: What do we know about wasting prevention? What is the emerging evidence? What are the evidence gaps and key questions which cannot currently be answered? What new evidence will be available in coming years?
A detailed review of the evidence from both published and grey literature and from semi-structured interviews with stakeholders was conducted between December 2017 and February 2018. The prevention of wasting was considered across the main intervention contexts (humanitarian and development, those with low and high levels of wasting/low and high levels of stunting), along a ‘continuum’ of severity (moderate and severe wasting and prevention of relapse). The review looked at the evidence for so-called nutrition-specific and nutrition-sensitive actions.
In total 235 studies and articles from the literature search were included in the review, of which 55 were randomised control trials, 23 were protocols/ongoing studies and 17 were systematic reviews. Fifty-seven grey literature documents were reviewed and 46 experts/key stakeholders were interviewed.
Historically there has been more of a focus on research into the prevention of stunting, while the prevention of wasting has been a more neglected research area. This is largely because the focus on wasting has been on treatment. Encouragingly, the review found that the volume of studies relating to wasting prevention has increased in recent years. However, the evidence base for the prevention of wasting is both mixed and largely inconclusive.
The interventions with the largest body of evidence include the use of supplementary food products, cash-based interventions, behaviour change to improve infant and young child feeding, and where interventions are combined. There is a lack of research on whether interventions targeted towards women and girls preconception and during pregnancy prevent wasting (see box 1 below).
The stakeholders consulted felt confident in stating that acute periods of food insecurity and/or episodes of disease outbreak contribute to wasting, and that well designed early interventions will have a preventive effect in such contexts. Despite an inconsistent evidence base, a holistic approach based on the UNICEF Conceptual Framework and context-specific causal analysis was advocated, through a range of interventions to tackle both the immediate and underlying drivers of undernutrition. It was felt that this should be complemented by an improved understanding of the epidemiology and aetiology of wasting to better identify and target children at highest risk.
Stakeholder opinion also suggested that much less is known about the prevention of wasting in non-humanitarian contexts or in areas with persistently high levels of wasting. Key gaps in the understanding of the aetiology of wasting were highlighted, including: kwashiorkor/ nutritional oedema; the relationship/overlap between stunting and wasting; differences relating to age and geography; the role of interventions preconception; the relationship between maternal nutrition and health status and child nutrition status; the extent to which wasting in infants under six months of age reflects non-nutritional factors (such as low birth weight); and mechanisms behind relapse after successful treatment for wasting. Other gaps included the role of infection and gut microbiota and the longer-term health and development impacts of childhood wasting.
Many stakeholders observed that there is an absence of a single organisation with an overall leadership role for wasting prevention. The divisions and silos which characterise wasting were also highlighted as a concern.
Box 1: Summary of state of evidence by intervention area
There is very little evidence of the impact of interventions to promote exclusive and continued breastfeeding on the prevention of wasting. Results are modest or difficult to attribute to an increase in breastfeeding alone.
Little evidence of the impact of complementary feeding interventions on preventing wasting was found. Some systematic reviews highlight the benefits, but studies including clear wasting outcomes are lacking.
Only small impacts on wasting prevention were observed when using zinc supplements, despite some high-quality systematic reviews and clinical trials in this intervention area.
Nutrition counselling and nutrition education
A number of randomised clinical trials (RCTs) in this intervention area showed positive effects on the prevention of wasting, although many still fail to demonstrate a clear impact.
Treating children known to have worm infection may have some nutritional benefits for the individual. However, despite some good quality studies, direct effects on preventing wasting have not been proved.
Maternal education, women’s empowerment and gender
Results predominantly from association studies and programme evaluations suggest that women’s empowerment interventions and education could have a positive impact on infant feeding and wasting.
Few clear studies consider the relationship between health interventions and prevention of wasting. Only a few well designed studies found a limited impact on wasting reduction.
Water, sanitation and hygiene (WASH)
There is currently very little evidence as to the direct effect of WASH interventions in the prevention of wasting, with the exception of some studies on sanitation.
Agriculture and other livelihoods
Only limited impacts have been observed, suggesting that more needs to be done to link increased agricultural production with improving child nutritional status. Robust evidence relating to the impact of livelihoods interventions on wasting prevention is also lacking.
General food distribution (GFD)
Although a number of studies have shown an impact of GFD on wasting, it is difficult to attribute this to the intervention alone.
Cash transfers (CTs)
There is a growing body of well designed trials that are demonstrating a strong positive preventive effect of CTs on wasting.
The highest number of studies was identified in this intervention area and evidence is growing quickly: well designed RCTs and systematic reviews have demonstrated the effect of food supplementation in preventing wasting, but questions around their cost-effectiveness and sustainability remain.
Combinations of interventions
The review found that a combination of interventions may be more effective at preventive wasting than separately implemented interventions, particularly when targeted to the same population.
The review identified numerous ongoing studies in the area of wasting prevention and some which are pending funding. Further evidence is anticipated in the coming years relating both to aetiology/epidemiology of wasting and effectiveness of various nutrition-specific and nutrition-sensitive interventions. Stakeholders stressed the importance of longer-term funding to facilitate research which encompasses the full 1,000 days window and a need for more longitudinal studies, including consideration of where existing data can be used (e.g. retrospective cohort studies). The need to improve the evidence base on drivers and effective approaches to wasting prevention through well designed programme monitoring and evaluation activities was also highlighted and several stakeholders supported the idea of a research prioritisation exercise.
ENN’s continued work in this area
ENN is continuing its focus on wasting prevention through the MQSUN+ mechanism by working with a team of experts to carry out a research prioritisation exercise on wasting prevention. This work will conclude in July 2019. Information on how you can participate in the exercise is available here.
ENN also continues to generate research publications and short briefs about the links between wasting and stunting (WaSt). Information about the WaSt project can be found here.
1ENN (2018) The current state of evidence and thinking on wasting prevention: MQSUN+ report. www.ennonline.net/resources/wastingpreventionreport2018
2ENN (2018) The aetiology of wasting: MQSUN+ report. www.ennonline.net/resources/aetiologyofwasting
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Reference this page
The current state of evidence and thinking on wasting prevention. Field Exchange 59, January 2019. p29. www.ennonline.net/fex/59/wastingprevention