ImportanceChild malnutrition kills about 3 million children every year, with 45% of all childhood deaths attributable in part to malnutrition.*1 Many more children suffer long-term health consequences from impaired physical growth. Wasting, or a low weight for a given height, is a measure of acute malnutrition. Wasting is a factor in 1 million child deaths every year.*1,2 Prevalence can vary dramatically over time due to seasonal food insecurity or disease outbreaks. Similarly, stunting, or a low height for a given age, is a measure of chronic malnutrition. Stunting is a major problem in low- and middle-income countries (LMICs); it is associated with a range of poor outcomes later in life, including poor cognitive development.*3 Most studies of wasting use cross-sectional data, and so cannot provide information on the longitudinal patterns in episode incidence, duration, and recovery. Cohorts with frequent measurements are generally small and therefore can’t examine regional or age-specific patterns in wasting. Examining the timing of wasting incidence using longitudinal measurements will help inform interventions to prevent the onset of wasting. Many children in low-resource settings become stunted early, often in the first 2 years of life, because they fail to grow as fast as well nourished infants. Understanding the underlying epidemiology of stunting, its primary risk factors, and the effect modifiers of existing interventions will help inform future intervention strategies.
- Combine standardized individual-level data from multiple datasets to summarize broad longitudinal and regional patterns in wasting incidence, duration, recovery, and severity.
- Examine longitudinal and regional patterns in stunting incidence, growth velocity, and catch-up growth.
- Identify and rank-order the child, parental, and household characteristics associated with wasting and stunting incidence.
Conclusion and RelevanceIn contrast to the common conception that wasting occurs mostly in children 12 months and older after they stop exclusively breastfeeding, wasting incidence was highest in the first 3 months of life, even when excluding children who were born wasted. Wasting was also highly seasonal, especially in South Asian countries, with peaks coinciding with the monsoon season. Prevalence of stunting increased from 13% at birth to 44% at 18 months and then plateaued. About half of stunted children experienced the onset of stunting in the first 6 months of life, including children who were born stunted. Therefore, it is possible that the most effective window for intervention is during the prenatal and early postnatal periods. Only 24% of children who experience any stunting were no longer stunted at 2 years of age. Although the factors that drive reversal require further research, few children have repeated episodes of stunting in the first 2 years of life. Prenatal factors, such as maternal height and BMI, are strongly associated with stunting. The association likely is a direct consequence of birth size, but it might also be related to other social and environmental factors. Children who experienced concurrent wasting and stunting, a condition with a high risk of mortality, first experienced both wasting and stunting in the first 6 months of life. These studies illuminate conditions that precede a wasting episode, patterns of wasting episodes, and factors in recovery from a wasting episode. Additionally, these studies provide a more comprehensive understanding of the epidemiology of stunting and the factors associated with stunting.
- Black RE, Victora CG, Walker SP, et al. Maternal and child undernutrition and overweight in low-income and middle-income countries. The Lancet. 2013;382(9890):427-451. doi:10.1016/S0140-6736(13)60937-X
- Ackatia-Armah RS, McDonald CM, Doumbia S, Erhardt JG, Hamer DH, Brown KH. Malian children with moderate acute malnutrition who are treated with lipid-based dietary supplements have greater weight gains and recovery rates than those treated with locally produced cereal-legume products: a community-based, cluster-randomized trial. Am J Clin Nutr. 2015;101(3):632-645. doi:10.3945/ajcn.113.069807
- Victora CG, Onis M de, Hallal PC, Blössner M, Shrimpton R. Worldwide Timing of Growth Faltering: Revisiting Implications for Interventions. Pediatrics. 2010;125(3):e473-e480. doi:10.1542/peds.2009-1519