The relationship between wasting and stunting: a retrospective cohort analysis of longitudinal data in Gambian children from 1976 to 2016
Summary of research1
Location: Gambia
What we know: There are gaps in understanding the relationship between wasting and stunting that often concur in populations and may concur in the same child.
What this article adds: A retrospective cohort analysis on growth-monitoring records from clinics in rural Gambia (1976 to 2016; 5,160 children under two years old) examined whether wasting is a risk factor for stunting, and vice versa; whether the season of birth influences future wasting and stunting; and whether there are gender differences in growth deficits in Gambia. Wasting was defined as weight-for-length z-score (WLZ) <-2. Stunting was defined as length-for-age z-score <-2. Wasting prevalence peaked at 12% (girls) and 18% (boys) at 10-12 months of age, and at 37% (girls) and 39% (boys) at 24 months of age. Wasted children were 3.2 times more likely to be stunted three months later, and children currently stunted were 1.5 times more likely to be wasted three months later. Infants born at the start of the annual wet season (July-October) showed early growth faltering (WLZ) and increased risk of subsequent stunting. Boys were more likely to be wasted, stunted and concurrently wasted and stunted than girls, and were more susceptible to seasonally-driven growth deficits. Results suggest that stunting is in part a biological response to previous episodes of being wasted. Where significant levels of wasting and stunting exist, treatment and prevention interventions should consider joint approaches. More understanding is needed of the physiologic mechanisms and environmental factors of seasonal vulnerabilities and gender differences in wasting and stunting.
Each year, around 800,000 deaths in children under five years of age are in part attributable to wasting; 60% of which are attributable to severe wasting. In addition, over one million child deaths are attributable to stunting, although this association remains poorly understood. Even though progress is being made in decreasing undernutrition in low- and middle-income countries, stunting and wasting during childhood continue to burden people in the poorest regions in the developing world. Although both forms of undernutrition occur together in children in many contexts and may co-occur in the same child (referred to as “concurrence”), wasting and stunting are often considered separately with respect to how they are managed clinically and programmatically and how they are researched. The rationale behind this conceptual separation of stunting and wasting in terms of etiology and programming has been questioned in several recent reviews and publications (Briend, Khara and Dolan, 2015; Khara and Dolan, 2014). These publications highlight outstanding gaps in understanding the interrelationship between these two forms of undernutrition as a result of insufficient examination of data; in particular from longitudinal cohorts.
The authors of this paper contribute to filling this gap by describing the interrelationships between wasting and stunting in children under two years old through a retrospective cohort analysis, based on growth-monitoring records spanning four decades from clinics in rural Gambia. Three broad research questions were tested: 1) is wasting a risk factor for stunting, and vice versa? 2) does the season of birth influence future wasting and stunting;? and 3) are there gender differences in growth deficits in the Gambia? Anthropometric data collected at scheduled infant-welfare clinics between May 1976 and September 2016 were converted to z-scores, comprising 64,342 observations on 5,160 subjects (median: 12 observations per individual). Children were defined as “wasted” if they had a weight-for-length z-score (WLZ) <–2 against the WHO reference and “stunted” if they had a length-for-age z-score (LAZ) <–2.
Results reveal that prevalence of wasting and stunting were high in this population. The prevalence of stunting increased with age, peaking at 37% (girls) and 39% (boys) at 24 months of age. Wasting showed an early decline in the first three months (reflecting a period of positive weight gain in the months immediately postpartum), followed by a peak at around one year of age (18% in boys, 12% girls). The prevalence of children with concurrence peaked at 9% in boys and 5% in girls, also at around one year of age. Infants who were wasted in the first wet season of their life were more likely to be wasted in their second wet season, even after controlling for recovering during the intervening dry season (OR:3.2; 95% CI:2.3, 4.4).
Infants born at the start of the annual wet season (July–October) showed early growth faltering in WLZ, putting them at increased risk of subsequent stunting. Time-lagged observations show that being wasted was predictive of stunting (OR: 3.2; 95% CI: 2.7, 3.9), even after accounting for current stunting. The reverse also holds: children currently stunted are 1.5 times more likely to be wasted three months later, even after accounting for currently wasting status. Boys were more likely to be wasted, stunted, and concurrently wasted and stunted than girls, as well as being more susceptible to seasonally-driven growth deficits.
This analysis highlights several key issues of relevance to our understanding of the relationship between wasting and stunting in early childhood. First, in this highly seasonal, rural environment with high rates of exclusive breastfeeding, there is a seasonally-driven risk among young infants of poor growth. This indicates the need to provide more targeted support to breastfeeding mothers and increase attention to infant feeding during periods of seasonal stress. Second, results demonstrate that being wasted leads to increased risk of subsequent stunting. This suggests that stunting is in part a biological response to previous episodes of being wasted and that stunting may represent a deleterious form of adaptation to more overt undernutrition (wasting). Stunted children are not just short, but are children who were earlier more seriously malnourished and who are survivors of a composite process. Third, children who are wasted in one wet season are more likely to be wasted in a subsequent wet season even after recovery, suggesting a continued vulnerability across seasons. Further understanding is needed of related physiologic mechanisms and environmental factors. Fourth, and consistent with much of the global literature, boys are more likely to be wasted or stunted or to have concurrent wasting and stunting; all of which convey added risk of mortality. There is a need to understand this gender difference in vulnerability so that the policy and practice communities can take this into account.
Results indicate that, where there are levels of wasting and stunting of public health significance in a given context, there are compelling reasons for both treatment and prevention interventions to consider wasting and stunting jointly and with awareness of the relation between them. The separation of the wasted infant/child and the stunted infant/child in terms of policies, programmes and research risks opportunities being missed to detect and intervene to prevent both forms of undernutrition in this highly-vulnerable population group. The attainment of World Health Assembly and other global targets remains a very strong global and country-level intent, but these targets will not be achieved where approaches to infant and child undernutrition remain siloed.
Endnotes
1Simon M Schoenbuchner, Carmel Dolan, Martha Mwangome, Andrew Hall, Stephanie A Richard, Jonathan C Wells, Tanya Khara, Bakary Sonko, Andrew M Prentice, Sophie E Moore. The relationship between wasting and stunting: a retrospective cohort analysis of longitudinal data in Gambian children from 1976 to 2016. The American Journal of Clinical Nutrition, Volume 110, Issue 2, August 2019, Pages 498–507, https://doi.org/10.1093/ajcn/nqy326
References
Briend A, Khara T, Dolan C. Wasting and stunting–similarities and differences: policy and programmatic implications. Food Nutr Bull 2015;36(1 Suppl):S15–23.
Khara T, Dolan C. Technical Briefing Paper: Associations between wasting and stunting, policy, programming and research implications. Oxford, UK: Emergency Nutrition Network; 2014.
More like this
FEX: 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...
Resource: The relationship between wasting and stunting: a retrospective cohort analysis of longitudinal data in Gambian children from 1976 to 2016
Abstract Background: The etiologic relationship between wasting and stunting is poorly understood, largely because of a lack of highquality longitudinal data from children at...
FEX: The relationship between wasting and stunting in young children: A systematic review
View this article as a pdf This article was written by Susan Thurstans, PhD candidate at the London School of Hygiene and Tropical Medicine and consultant to ENN on the...
FEX: The Wasting-Stunting Technical Interest Group: A summary of the work to date
View this article as a pdf Lisez cet article en français ici This article outlines the work of the Wasting-Stunting Technical Interest Group since its inception in...
FEX: The Wasting-Stunting Technical Interest Group: Summarising the work to date
This is a summary of a Field Exchange field article that was included in issue 67. The original article was authored by Natalie Sessions and Tanya Khara. Natalie Sessions is a...
FEX: Concurrent wasting and stunting among under-five children in Senegal
Research snapshot1 The study describes the patterns of concurrent wasting and stunting (WaSt) among children age 6-59 months living in the 1980s in Niakhar, a rural area of...
Wasting and Stunting-making progress on understanding the links
Friday 16th February, 2017 By Carmel Dolan, ENN Technical Director Some of you will know that ENN has been coordinating a project with the expert steer of around 30 child...
FEX: Making connections: Joint meeting of WaSt Technical Interest Group and MAMI Special Interest Group
ENN coordinates two international technical groups, the Management of at-risk Mothers and Infants under six months Special Interest Group (MAMI SIG) and the Wasting and...
FEX: Understanding sex differences in childhood malnutrition
View this article as a pdf This is a summary of the following paper: Thurstans S, Opondo C, Seal A, Wells J, Khara T, Dolan C et al (2021) Understanding sex differences in...
FEX: Predicting coexistence of wasting and stunting in Guinea-Bissau: A secondary data analysis
Summary of MSc thesis1 By Abbi Sage Abbi Sage is a recent MSc graduate in Nutrition for Global Health from the London School of Hygiene and Tropical Medicine. She is now part...
FEX: A reflection on the 2021 Lancet Maternal & Child Nutrition Series through a WaSt lens
View this article as a pdf This article provides a summary of the Lancet Maternal & Child Nutrition Series to date, reflecting upon the 2021 series from the perspective of the...
Blog post: Wasting and Stunting-making progress on understanding the links
Some of you will know that ENN has been coordinating a project with the expert steer of around 30 child growth and nutrition specialists from academia, donor and operational...
FEX: Child wasting and stunting: Time to overcome the separation
A briefing note for policy-makers and programme implementers was released in June 2018 by the ENN-coordinated Wasting-Stunting Technical Interest Group (WaSt TIG). The brief,...
FEX: Stunting and wasting in children under two years old in a semi-nomadic pastoralist population in Kenya
By Amelia Reese-Masterson, Masumi Maehara and Mark Murage Gathii Amelia Reese-Masterson is Research Advisor in the Nutrition, Food Security and Livelihoods Unit at...
WaSt TIG - the work so far
We have had three phases of work thus far and are currently in the fourth. A special section in FEX summarises a lot of the work of the WaSt TIG so far as well as experiences...
FEX: Children concurrently wasted and stunted: A meta- analysis of prevalence data of children 6-59 months from 84 countries
Research summary1 Location: Global What we know: Wasting and stunting are often present in the same geographical populations and can exist concurrently in the same children,...
Resource: Concurrent wasting and stunting among under-five children in Niakhar, Senegal
Abstract The study describes the patterns of concurrent wasting and stunting (WaSt) among children age 6-59 months living in the 1980s in Niakhar, a rural area of Senegal...
FEX: Growth faltering in rural Gambian children after four decades of interventions: a retrospective cohort study
Summary of Research1 Nabwera HM, Fulford AJ, Moore SE and Prentice AM. (2017). Growth faltering in rural Gambian children after four decades of interventions: a retrospective...
FEX: A systematic review and meta-analysis of sex differences in undernutrition
View this article as a pdf Research snapshot1 Despite considerable research into childhood sex differences in neonatal and infant health, different disciplines tend to hold...
en-net: Concurrent wasting and stunting among under‐five children
Here is an article on Concurrent wasting and stunting among under‐five children in Senegal. Abstract The study describes the patterns of concurrent wasting and stunting...
Reference this page
The relationship between wasting and stunting: a retrospective cohort analysis of longitudinal data in Gambian children from 1976 to 2016. Field Exchange 61, November 2019. p26. www.ennonline.net/fex/61/cohortanalysisgambia
(fex.61.521)