Wasting and Stunting Technical Interest Group (WaSt TIG) meeting
On the 15th of January 2018 the Wasting and Stunting (WaSt) Technical Interest Group (TIG) held their third face-to-face meeting at Trinity College, Oxford. This group of 30 experts1 in child growth, nutrition, and epidemiology, was formed in January 2014 to guide the ENN’s WaSt project2 (funded by USAID/OFDA and Irish Aid). A separation in the nutrition sector in the conceptualisation of child wasting and stunting over recent decades, along the humanitarian/development divide, has resulted in the evolution of separate policy, programmes, research and funding for these two manifestations of undernutrition. The WaSt TIG coordinated by the ENN have been working over the last four years to improve our understanding of the relationship between wasting and stunting to find out if this separation is justified.
Having published a research prioritisation in 2016 (Angood et al, 2016) the WaSt TIG have subsequently, prompted by a limited funding base, available datasets and enthusiasm of its members, focused on mining existing data to answer some of these priority questions. The meeting brought together the members of the group to present and discuss analyses on the relationship between wasting and stunting carried out over the last two years on existing data by TIG members; agree upon the policy, programme and research implications of the findings of these analysis; and define future priorities for the WaSt TIG.
Carmel Dolan (ENN) opened the meeting, thanking participants for their ongoing enthusiastic engagement over the last four years, welcoming new members, and recapping on the work of the WaSt TIG during that time.
Tanya Khara (ENN) presented a meta-analysis of prevalence and burden of children concurrently wasted and stunted (weight-for-height z score (WHZ) <-2 AND height-for-age z score (HAZ) <-2, or concurrent WaSt) in 84 countries from MICS/DHS3 datasets. This analysis, published in October 2017 (Khara et al, 2018), was born out of concern for the apparent high risk of death associated with multiple anthropometric deficits and the lack of reporting on the overlap between wasting and stunting, despite the data being available routinely. Key findings presented included:
- Concurrent WaSt ranged from 0-8% (in children aged 6-59 months); with nine countries >5%.
- Pooled prevalence was 3.0% (95% CI 2.97 to 3.06) signifying a burden of approximately six million children (6-59 months) in the 84 countries.
- Concurrent WaSt was highest in the 12- 24 months age group and more common in boys.
It was emphasised that this analysis is not a global one as national data from the last 10 years was only available for 84 countries. The work has had influence however, with the WHO/UNICEF 2016 Joint Estimates report recognising that we don’t know the level of concurrence globally, www.who.int/nutgrowthdb/estimates4.
Mark Myatt (Brixton Health) presented analysis of 2,426 cross sectional surveys conducted between 1992 and 2015 of almost 1.8 million children in 51 countries. The key finding of this analysis, already submitted for publication, was confirmed by modelling using the WHO growth standards themselves - it is impossible to be WHZ <-2 z score AND HAZ <-2 z score and not be weight-for-age (WAZ) <-2 z score. This means that the highly elevated risk of death for children concurrently wasted, stunted and underweight (hazard ratio of 12.3 compared to children with no anthropometric deficits) found in analysis of 10 mortality cohorts (McDonald et al, 2013), is actually the mortality risk for children concurrently wasted and stunted.
Additional findings of this analysis were:
- In most countries for which we have data, stunting and wasting are associated with each other; wasted children are more likely to be stunted (than non-wasted children) and stunted children more likely to be wasted (than non-stunted children).
- Children with concurrent WaSt are more wasted than children who are wasted only and more stunted than children who are stunted only.
- Concurrent WaSt is more prevalent in younger children, and in boys.
- Children who are both stunted and wasted can be detected with excellent sensitivity and very good specificity using WAZ and with acceptable sensitivity and specificity using MUAC.
Further analysis was also presented and discussed exploring the relationship between being both wasted and stunted and mortality. This particularly explored whether it is all or a subset of children with concurrent WaSt that were most at risk of mortality and what indices/case-definitions would be most appropriate to identify those cases at most risk of dying who may need to be treated within community based management of acute malnutrition (CMAM) programmes. Preliminary findings from analysis of longitudinal data from Niakhar in Senegal comprising 5,144 children who were followed without treatment was presented and issues such as factoring age into the analysis and the caseload implications of looking at WAZ as a means of identifying high risk children with concurrent WaSt were discussed.
Sophie Moore (Medical Research Council (MRC) Unit, The Gambia at the London School of Hygiene and Tropical Medicine & Department of Women and Children’s Health, King’s College London, London) and Simon Schoenbuchner (MRC Elsie Widdowson Laboratory, Cambridge) presented analysis of MRC cohort data from The Gambia, which retrospectively examined infant and child (birth to two years of age) nutritional status from three long-standing MRC surveillance villages (1976-2012). Key findings included:
- Season of birth is a predictor of growth patterns; children who are born at the start of the annual wet season fail to thrive in the early post-natal months.
- Children who are wasted in the wet season, even if they recover weight in the dry season, are more likely to be wasted again in the next wet season.
- At the peak prevalence, 10% of boys were concurrently wasted and stunted, compared to 5% of girls.
- Current wasted status increases a child’s odds of being stunted in three months’ time by a factor of 3.2; current stunted status increases the odds of the child being wasted in three months’ time by a factor of 1.5.
The important implications of these analyses for programmes and policy were discussed at length by the WaSt TIG, also considering other analysis of data from children during and after treatment for severe acute malnutrition (SAM) presented at the meeting by Sheila Isanaka (Harvard) and Jay Berkley (KEMRI), and in light of current initiatives within the nutrition sector. The WaSt TIG decided to produce two briefing documents, one focused on policy and the other on programme implications for wide circulation, followed by a Lancet views piece which will propose a bold reframing of how we understand wasting and stunting. The group also agreed to meet remotely to discuss other specific priority pieces of follow-up work in 2018 which may include seeking permission to access additional mortality cohorts for similar analysis and further exploration of the heightened male vulnerability demonstrated in analysis conducted so far.
For additional information about the ENN’s WaSt project and the WaSt TIG, please contact Tanya Khara.
References
Angood C, Khara T, Dolan C, Berkley JA, WaSt Technical Interest Group (2016) Research Priorities on the Relationship between Wasting and Stunting. PLoS ONE 11(5): e0153221. https://doi.org/10.1371/journal.pone.0153221
Khara T, Mwangowe. M, Ngari M, Dolan C. 2018. Children concurrently wasted and stunted: A meta- analysis of prevelance data of children 6-59 months from 84 countries. Mater Child https://onlinelibrary.wiley.com/doi/full/10.1111/mcn.12516
McDonald, CM., I. Olofin, S. Flaxman, W. W. Fawzi, D. Spiegelman, L. E. Caulfield, R. E. Black, M. Ezzati, and G. Danaei. 2013. The Effect of Multiple Anthropometric Deficits on Child Mortality: Meta-Analysis of Individual Data in 10 Prospective Studies from Developing Countries. American Journal of Clinical Nutrition 97 (4): 896–901. doi:10.3945/ajcn.112.047639
Endnotes
1https://www.ennonline.net/ourwork/researchandreviews/wast/wasttigmembers
2https://www.ennonline.net/ourwork/reviews/wastingstunting
3Multiple Indicator Cluster Survey/Demographic and Health Survey
4A postscript to this is that since the meeting UNICEF has published online figures for the prevalence of children concurrently wasted and stunted (‘overlapping malnutrition estimates’) for all the national surveys in its database. https://data.unicef.org/topic/nutrition/malnutrition/