How Seasonality of Malnutrition Is Measured and Analyzed

Peak timing of slowest growth velocity among young children coincides with highest ambient temperatures in Burkina Faso: a longitudinal study

BACKGROUND

Seasonal cycles in climatic factors affect drivers of child growth and contribute to seasonal fluctuations in undernutrition. Current growth seasonality models are limited by categorical definitions of seasons that rely on assumptions about their timing and fail to consider their magnitude.

OBJECTIVE

We disentangle the relationship between climatic factors and growth indicators, using harmonic regression to determine how child growth is related to peaks in temperature, precipitation, and vegetation.

METHODS

Longitudinal anthropometric data collected between August 2014 and December 2016 from 5039 Burkinabè children measured monthly from age 6 to 28 mo (108,580 observations) were linked with remotely sensed daily precipitation, vegetation, and maximum air temperature. Our models parsimoniously extract a cyclic signal with multiple potential peaks, to compare the magnitude and timing of seasonal peaks in climatic factors and morbidity with that of nadirs in growth velocity (cm/mo, kg/mo).

RESULTS

Length and weight velocity were slowest twice a year, coinciding both times with the highest temperatures, and peak fever incidence. Length velocity is slowest 13 d after the first temperature peak in April, and 5 d after the second. Similarly, weight velocity is slowest 13 d before the first temperature peak, and 11 d before the second. The statistical relationship between temperature and anthropometry shows that when the current temperature is higher, weight velocity is lower (β = -0.0048; 95% CI: -0.0059, -0.0038), and length velocity is higher (β = 0.0088; 95% CI: 0.0070, 0.0105).

CONCLUSIONS

Results suggest that child health and development are more affected by high temperatures than by other aspects of climatic seasonality such as rainfall. Emerging shifts in climatic conditions will pose challenges to optimal growth, highlighting the importance of changes that optimize the timing of nutrition interventions and address environmental growth-limiting conditions.

CLINICAL TRIAL REGISTRY

Clinicaltrials.gov: NCT02071563.

The Complexity of the Seasonality of Nutritional Status: Two Annul Peaks in Child Wasting in Eastern Chad

BACKGROUND

Understanding seasonal patterns in nutritional status is critical for achieving and tracking global nutrition goals. However, the majority of nutrition seasonality research design draws on 2 or 3 within-year time points based on existing assumptions of seasonality, missing a more nuanced pattern.

OBJECTIVE

We aimed to identify the intra-year variability of childhood wasting, severe wasting, and weight-for-height z-scores (WHZ) in a dryland single wet-season context and illustrate an analytical approach for improving analysis of the seasonality of nutritional status.

METHODS

To quantify the intra-year variability in nutritional status, we use data from a 23-month panel study (May 2018 to March 2020) following 231 children (6-59 months of age) in eastern Chad. We apply a mixed-effects harmonic regression with child- and village-level fixed effects on the odds of being wasted, severely wasted, and on WHZ, testing for multiple and nonsymmetrical seasonal peaks, adjusted for child sex and age. We triangulate our findings using climate data on temperature, vegetation, and precipitation.

RESULTS

We identify 2 annual peaks of wasting and severe wasting. Wasting peaks at 14.7% (confidence interval [CI], 11.8-18.2) at the end of the dry season, while the smaller peak corresponds to the start of the harvest period at 13.4% (CI, 10.7-16.6). The odds of being wasted decline during the rainy season to 11.8% (CI, 9.4-14.7), with the lowest prevalence of 8.8% (CI, 6.9-11.1) occurring during the start of the dry season. In addition, a 1°C monthly increase in temperature is significantly associated with a 5% (CI, 1.4-8.7) and 12% (CI, 3.0-20.3) increase in the odds that a child is wasted and severely wasted, respectively.

CONCLUSIONS

Intra-year variability of child wasting is far more complex and nuanced than identified by the literature, with 2 peaks, as opposed to 1, likely corresponding to different seasonal drivers, such as food insecurity, disease, water contamination, and care practices at different times of year. Better seasonality analysis can go a long way in improving the timing and content of programming with the goal of reducing child wasting.

Seasonality of Acute Malnutrition in African Drylands: Evidence From 15 Years of SMART Surveys

Reduction of wasting, or low weight-for-height, is a critical target for the Zero Hunger Sustainable Development Goal, yet robust evidence establishing continuous seasonal patterns of wasting is presently lacking. The current consensus of greatest hunger during the preharvest period is based on survey designs and analytical methods, which discretize time frame into preharvest/postharvest, dry/wet, or lean/plenty seasons. We present a spatiotemporally nuanced study of acute malnutrition seasonality in African drylands using a 15-year data set of Standardized Monitoring and Assessment of Relief and Transition surveys (n = 412,370). Climatological similarity was ensured by selecting subnational survey regions with 1 rainy season and by spatially matching each survey to aridity and livelihood zones. Harmonic logit regression models indicate 2 peaks of wasting during the calendar year. Greatest wasting prevalence is estimated in April to May, coincident with the primary peak of temperature. A secondary peak of wasting is observed in August to October, coinciding with the primary peak of rainfall and secondary peak of temperature. This pattern is retained across aridity and livelihood zones and is sensitive to temperature, precipitation, and vegetation. Improved subnational estimation of acute malnutrition seasonality can thus assist decision makers and practitioners in data-sparse settings and facilitate global progress toward Zero Hunger.

Forecasting Seasonal Acute Malnutrition: Setting the Framework

BACKGROUND

Malnutrition is an umbrella term that refers to an impairment in nutrition indicative of subsequently compromised human well-being. The term covers the full spectrum of nutritional impairments from a small yet detectable departure from a "norm" to a terminal stage when severe malnutrition could result in death. This broad spectrum of nutritional departures from "the optimum" dictates the need for an ensemble of metrics to capture the complexity of involved mechanisms, risk factors, precipitating events, short-term, and long-term consequences. Ideally, these metrics should be universally applicable to vulnerable populations, settings, ages, and times when people are most susceptible to malnutrition. We should be able to characterize and intervene to minimize the risk of malnutrition, especially child acute malnutrition that could be assessed by anthropometric measurements.

OBJECTIVES

The main challenge in reaching such an ambitious goal is the complexity of measuring, characterizing, explaining, predicting, and preventing malnutrition at any dimension: temporal or spatial and at any scale: a person or a group. The expansive body of literature has been accumulated on many temporal aspects of malnutrition and seasonal changes in nutritional (anthropometric) status. The research community is now shifting their attention to predictive modeling of child malnutrition and its importance for clinical and public health interventions. This communication aims to provide an overview of challenges for understanding child malnutrition from a perspective of predictive modeling focusing on well-documented seasonal variations in nutritional outcomes and exploring "the systems approach" to tackle underlining conceptual and practical complexities to forecast seasonal malnutrition in an accurate and timely manner. This generalized approach to forecasting seasonal malnutrition is then applied specifically to child acute malnutrition.

Restoring Food Systems with Nutritious Native Plants: Experiences from the African Drylands

BACKGROUND

Twenty-seven African countries have committed to restore more than 100 million hectares of degraded land by 2030 as part of the African Forest Landscape Restoration Initiative (AFR100). In addition, for the same period of time, the African-led Great Green Wall initiative seeks to restore 100 million hectares of degraded agro-sylvo-pastoral lands in the Sahel. The current UN Decade on Ecosystem Restoration (2021-2030) moreover marks an unprecedented opportunity to shape future landscapes, and forge more biodiverse and nutritious food systems. Yet most large-scale restoration actions continue to be largely isolated from socioeconomic challenges facing dryland communities, not least food security and acute malnutrition. Such isolations contribute to low restoration successes and outcomes in Africa's drylands. At the same time, international interventions aimed at improving acute malnutrition in the drylands have not adequately considered the agriculture-nutrition linkages, particularly "pre-farm gate"-including consumption pathways which optimize the use of native plant diversity.

OBJECTIVES

This article identifies priority action areas emerging from experiences over 5 years of restoration activities carried out in the Sahel through Food and Agriculture Organization's (FAO) Action Against Desertification Programme supporting the implementation of Africa's Great Green Wall. These actions aim to inform development and humanitarian interventions on the ground to render restoration interventions nutrition-sensitive and hence more effective in practice.

RESULTS

Recognizing the symbiotic relationship between landscapes and livelihoods, FAO developed a blueprint for large-scale restoration that combines biophysical and socioeconomic aspects for the benefit of rural communities. The approach builds climate and nutritional resilience into its restoration interventions as a preventative approach to reverse land degradation and ultimately improve livelihoods, food security, and nutrition.

CONCLUSIONS

FAO's experience demonstrated that what is planted and when has the potential to not only significantly improve biodiversity and reverse land degradation, but also positively influence nutrition outcomes. Future interventions in the drylands must involve joint efforts between nutritionists and natural resource managem prove both human and planetary health.

PROTOCOL: The impact of infrastructure on low income consumers' nutritious diet, women's economic empowerment, and gender equality in low-and middle-income countries: An evidence and gap map

This is the protocol for an evidence and gap map. The objectives are as follows: this evidence and gap map (EGM) aims to identify, map, and provide an overview of the existing evidence and gaps on the impact of different types of physical infrastructure on various outcomes of low-income consumers' nutritious diet, women's economic empowerment, and gender equality in low- and middle-income countries. The specific objectives of the EGM are: (1) identify clusters of evidence that offer opportunities for evidence synthesis and (2) identify gaps in evidence where new studies, research, and evaluations are needed.

Foundational Nutrition: Implications for Human Health

Human nutrition, and what can be considered "ideal" nutrition, is a complex, multi-faceted topic which many researchers and practitioners deliberate. While some attest that basic human nutrition is relatively understood, it is undeniable that a global nutritional problem persists. Many countries struggle with malnutrition or caloric deficits, while others encounter difficulties with caloric overconsumption and micronutrient deficiencies. A multitude of factors contribute to this global problem. Limitations to the current scope of the recommended daily allowances (RDAs) and dietary reference intakes (DRIs), changes in soil quality, and reductions in nutrient density are just a few of these factors. In this article, we propose a new, working approach towards human nutrition designated "Foundational Nutrition". This nutritional lens combines a whole food approach in conjunction with micronutrients and other nutrients critical for optimal human health with special consideration given to the human gut microbiome and overall gut health. Together, this a synergistic approach which addresses vital components in nutrition that enhances the bioavailability of nutrients and to potentiate a bioactive effect.

S, Jana S, Subramanian SV, Unisa S. Role of seasonality variation in prevalence and trend of childhood wasting in India: An empirical analysis using National Family Health Surveys, 2005-2021

Background

Wasting develops over a short period and can be reversed with short-term interventions. The prevalence of wasting typically varies from season to season-becoming higher during the monsoon (June to September) season as compared to the winter (October to January) and summer (February to May) seasons every year in a cyclical fashion. However, to the best of our knowledge, using nationally representative demographic surveys to extensively study the impact of the timing of the survey on the results and trends around wasting has not been done so far.

Objectives

The goal of this study is to ascertain whether seasonality has an impact on the trend and levels of wasting between NFHS-3 (2005-2006) and NFHS-5 (2019-2021).

Methods

The analysis was based on data on 51,555, 259,627, and 232,920 children under 5 years included in NFHS-3, NFHS-4, and NFHS-5 respectively. Multivariable logistic regression analysis and the predicted probabilities approach were employed to examine the effect of the months of interview on the prevalence of wasting. The analysis was conducted for 9 states of India which had data for comparable months to compute wasting levels.

Results

We found that at the national level, wasting increased in India by one per cent from NFHS-3 to NFHS-4 but declined by 2% from NFHS-4 to NFHS-5. The results show that seasonality significantly influenced the prevalence of wasting. It was observed that compared to January, the odds of wasting were particularly higher in summer and monsoon seasons, especially in the month of August across all three rounds, indicating the influence of seasonality in the prevalence of wasting in the country.

Discussion

The prevalence of wasting in India needs to be interpreted across seasonal changes as seasonality affects many of the variables intrinsically related to child health and nutritional status.

How Can Nutrition Research Better Reflect the Relationship Between Wasting and Stunting in Children? Learnings from the Wasting and Stunting Project

Childhood wasting and stunting affect large numbers of children globally. Both are important risk factors for illness and death yet, despite the fact that these conditions can share common risk factors and are often seen in the same child, they are commonly portrayed as relatively distinct manifestations of undernutrition. In 2014, the Wasting and Stunting project was launched by the Emergency Nutrition Network. Its aim was to better understand the complex relationship and associations between wasting and stunting and examine whether current separations that were apparent in approaches to policy, financing, and programs were justified or useful. Based on the project's work, this article aims to bring a wasting and stunting lens to how research is designed and financed in order for the nutrition community to better understand, prevent, and treat child undernutrition. Discussion of lessons learnt focuses on the synergy and temporal relationships between children's weight loss and linear growth faltering, the proximal and distal factors that drive diverse forms of undernutrition, and identifying and targeting people most at risk. Supporting progress in all these areas requires research collaborations across interest groups that highlight the value of research that moves beyond a focus on single forms of undernutrition, and ensures that there is equal attention given to wasting as to other forms of malnutrition, wherever it is present.

Linear Growth Spurts are Preceded by Higher Weight Gain Velocity and Followed by Weight Slowdowns Among Rural Children in Burkina Faso: A Longitudinal Study

BACKGROUND

The temporal relationship between length (linear) and weight (ponderal) growth in early life is important to support optimal nutrition program design. Studies based on measures of attained size have established that wasting often precedes stunting, but such studies do not capture responsiveness of growth to previous compared with current conditions. As a result, the temporality of linear and ponderal growth relationships remain unclear.

OBJECTIVES

We used growth velocity indicators to assess the temporal bidirectional relationships between linear and ponderal growth in children.

METHODS

Using monthly anthropometric measurements from 5039 Burkinabè children enrolled at 6 months of age and followed until 28 months from August 2014 to December 2016, we employed multilevel mixed-effects models to investigate concurrent and lagged associations between linear and ponderal growth velocity, controlling for time trends, seasonality, and morbidity.

RESULTS

Faster ponderal growth is associated with faster concurrent and subsequent linear growth (0.21-0.72 increase in length velocity z-score per unit increase in weight velocity z-score), while faster linear growth is associated with slower future weight gain (0.009-0.02 decrease in weight velocity z-score per unit increase in length velocity z-score), especially among children 9-14 months. Ponderal growth slows around the same time as peaks in morbidity, followed roughly a month later by slower linear growth.

CONCLUSIONS

Use of velocity measures to assess temporal dependencies between linear and ponderal growth demonstrate that the same growth-limiting conditions likely affect both length and weight velocity, that slow ponderal growth likely limits subsequent linear growth, and that linear growth spurts may not be accompanied by sufficient increases in dietary intake to avoid slowdowns in weight gain.

Methods for assessing seasonal and annual trends in wasting in Indian surveys (NFHS-3, 4, RSOC & CNNS)

Wasting in children under-five is a form of acute malnutrition, a predictor of under-five child mortality and of increased risk of future episodes of stunting and/or wasting. In India, national estimates of wasting are high compared to international standards with one in five children found to be wasted. National surveys are complex logistical operations and most often not planned or implemented in a manner to control for seasonality. Collection of survey data across differing months across states introduces seasonal bias. Cross-sectional surveys are not designed to collect data on seasonality, thus special methods are needed to analyse the effect of data collection by month. We developed regression models to estimate the mean weight for height (WHZ), prevalence of wasting for every month of the year for an average year and an overall weighted survey estimates controlling for the socio-demographic variation of data collection across states and populations over time. National level analyses show the mean WHZ starts at its highest in January, falls to the lowest in June/August and returns towards peak at year end. The prevalence of wasting is lowest in January and doubles by June/August. After accounting for seasonal patterns in data collection across surveys, the trends are significantly different and indicate a stagnant period followed by a decline in wasting. To avoid biased estimates, direct comparisons of acute malnutrition across surveys should not be made unless seasonality bias is appropriately addressed in planning, implementation or analysis. Eliminating the seasonal variation in wasting would reduce the prevalence by half and provide guidance towards further reduction in acute malnutrition.