evidence-based blog of Filippo Dibari

Posts Tagged ‘WHO growth standards’

Associations of Suboptimal Growth with All-Cause and Cause-Specific Mortality in Children under Five Years: A Pooled Analysis of Ten Prospective Studies

In Under-nutrition on June 3, 2016 at 3:38 pm

Olofin I, McDonald CM, Ezzati M, Flaxman S, Black RE, et al. (2013) Associations of Suboptimal Growth with All-Cause and Cause-Specific Mortality in Children under Five Years: A Pooled Analysis of Ten Prospective Studies. PLoS ONE 8(5): e64636.

(download)

Abstract

 

Background

Child undernutrition affects millions of children globally. We investigated associations between suboptimal growth and mortality by pooling large studies.

Methods

Pooled analysis involving children 1 week to 59 months old in 10 prospective studies in Africa, Asia and South America. Utilizing most recent measurements, we calculated weight-for-age, height/length-for-age and weight-for-height/length Z scores, applying 2006 WHO Standards and the 1977 NCHS/WHO Reference. We estimated all-cause and cause-specific mortality hazard ratios (HR) using proportional hazards models comparing children with mild (−2≤Z<−1), moderate (−3≤Z<−2), or severe (Z<−3) anthropometric deficits with the reference category (Z≥−1).

Results

53 809 children were eligible for this re-analysis and contributed a total of 55 359 person-years, during which 1315 deaths were observed. All degrees of underweight, stunting and wasting were associated with significantly higher mortality. The strength of association increased monotonically as Z scores decreased. Pooled mortality HR was 1.52 (95% Confidence Interval 1.28, 1.81) for mild underweight; 2.63 (2.20, 3.14) for moderate underweight; and 9.40 (8.02, 11.03) for severe underweight. Wasting was a stronger determinant of mortality than stunting or underweight. Mortality HR for severe wasting was 11.63 (9.84, 13.76) compared with 5.48 (4.62, 6.50) for severe stunting. Using older NCHS standards resulted in larger HRs compared with WHO standards. In cause-specific analyses, all degrees of anthropometric deficits increased the hazards of dying from respiratory tract infections and diarrheal diseases. The study had insufficient power to precisely estimate effects of undernutrition on malaria mortality.

Conclusions

All degrees of anthropometric deficits are associated with increased risk of under-five mortality using the 2006 WHO Standards. Even mild deficits substantially increase mortality, especially from infectious diseases.

An evaluation of an operations research project to reduce childhood stunting in a food-insecure area in Ethiopia

In Under-nutrition on August 28, 2012 at 8:52 pm

by Bridget Fenn, Assaye T Bulti, Themba Nduna, Arabella Duffield and Fiona Watson

Public Health Nutrition / Volume 15 / Issue 09 / September 2012 , pp 1746-1754

Abstract

Objective To determine which interventions can reduce linear growth retardation (stunting) in children aged 6–36 months over a 5-year period in a food-insecure population in Ethiopia.

Design We used data collected through an operations research project run by Save the Children UK: the Child Caring Practices (CCP) project. Eleven neighbouring villages were purposefully selected to receive one of four interventions: (i) health; (iii) nutrition education; (iii) water, sanitation and hygiene (WASH); or (iv) integrated comprising all interventions. A comparison group of three villages did not receive any interventions. Cross-sectional surveys were conducted at baseline (2004) and for impact evaluation (2009) using the same quantitative and qualitative tools. The primary outcome was stunted growth in children aged 6–36 months measured as height (or length)-for-age Z-scores (mean and prevalence). Secondary outcomes were knowledge of health seeking, infant and young child feeding and preventive practices.

Setting Amhara, Ethiopia.

Subjects Children aged 6–36 months.

Results The WASH intervention group was the only group to show a significant increase in mean height-for-age Z-score (+0·33, P = 0·02), with a 12·1 % decrease in the prevalence of stunting, compared with the baseline group. This group also showed significant improvements in mothers’ knowledge of causes of diarrhoea and hygiene practices. The other intervention groups saw non-significant impacts for childhood stunting but improvements in knowledge relating to specific intervention education messages given.

Conclusions The study suggests that an improvement in hygiene practices had a significant impact on stunting levels. However, there may be alternative explanations for this and further evidence is required.

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An effectiveness trial showed lipid-based nutrient supplementation but not corn–soya blend offered a modest benefit in weight gain among 6- to 18-month-old underweight children in rural Malawi

In Under-nutrition on August 28, 2012 at 8:44 pm

by Chrissie M Thakwalakwa, Per Ashorn, Mpumulo Jawati, John C Phuka, Yin Bun Cheung and Kenneth M Maleta

Public Health Nutrition / Volume 15 / Issue 09 / September 2012 , pp 1755-1762

Abstract

 Objective To determine if supplementation with corn–soya blend (CSB) or lipid-based nutrient supplement (LNS) improved the weight gain of moderately underweight infants and children when provided through the national health service.

Design A randomised, controlled, assessor-blinded clinical trial. Infants and children were randomised to receive for 12 weeks an average daily ration of 71 g CSB or 43 g LNS, providing 1188 kJ and 920 kJ, respectively, or no supplement (control). Main outcome was weight gain. Secondary outcomes included changes in anthropometric indices and incidence of serious adverse events. Intention-to-treat analyses were used.

Setting Kukalanga, Koche, Katema and Jalasi health centres in Mangochi District, rural Malawi.

Subjects Underweight (weight-for-age Z-score <−2) infants and children aged 6–15 months (n 299).

Results Mean weight gain was 630 g, 680 g and 750 g in control, CSB and LNS groups, respectively (P = 0·21). When adjusted for baseline age, children receiving LNS gained on average 90 g more weight (P = 0·185) and their weight-for-length Z-score increased 0·22 more (P = 0·049) compared with those receiving no supplementation. No statistically significant differences were observed between the CSB and control groups in mean weight and length gain.

Conclusions LNS supplementation provided during the lean season via through the national health service was associated with a modest increase in weight. However, the effect size was lower than that previously reported under more controlled research settings.

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Context-specific choice of food aid items (USAID)

In Under-nutrition on August 12, 2012 at 10:22 am


(click directly on the flowchart for an enlarged view)

In a recent document (2011), USAID, in collaboration with the UN Global Nutrition Cluster, UNHCR WFP and other organizations, suggest which type of programme and food commodities are more adequate.

However, it was concluded that there is no one food product that can meet every kind of programming goal, and no one programming approach that fits all needs.

The same panel  developed decision trees and few flow charts to help policy makers and donors in taking more informed decisions about programmes and choice of food-products.

The original program guidance is available here, whereas another version of the same, visible above, was adjusted in one chapter of my PhD thesis.

Finally! Everything, really everything, about treatment of undernutrition (CMAM). In just-one-click-away, comprehensive, interactive, open-access, website.

In Under-nutrition on July 10, 2012 at 10:42 am

A new electronic forum improves the management of acute malnutrition. Worldwide.

In this area of humanitarian intervention, CMAM is the acronym mostly used: Community-based Management of Acute Malnutrition.

The CMAM forum not only hosts e-discussions about this topic, but also collects all the key documents endorsed by the WHO, other UN agencies, national and international NGOs. Otherwise scattered around, in their web sites.

World experts in this field (Andre’ Briend, and Mark Myatt among them) support this forum. Therefore, the target consists of practitioners rather than the general public.

The main focus list of the e-forum includes:

  • malnutrition and HIV/AIDS
  • malnutrition and infants, children, adolescents and adults, whose specificities are treated separately
  • malnutrition and health systems in the individual countries
  • evidence for action aiming policy-making, advocacy, support in the area of malnutrition treatment
  • product development for malnutrition rehabilitation
  • current research and existing evidences about most of the topics mentioned above
The web site has important tools:
  • you are interested in CMAM in a specific country? Visit the country section of the CMAM web forum
  • you wish to receive notices about meetings, conferences, trainings? You want to ask questions, learn how to calculate case loads, or simply follow up other people’s questions? Create your website account (for free)
  • you are interested in the latest evidence-based documents or the current state of research? Visit the related section of the forum
  • you can also contribute sharing, with the other forum members, the lessons learnt from your community-based feeding programme

This important forum was conceived thanks to the effort of many organizations. However, the realization was led by Valid International and Action Against Hunger.

If you find the CMAM forum interesting, do not hesitate to re-blog this post, or forward the link of the forum to relevant people.

If you have some constructive criticism or ideas to improve this new important tool, I encourage you to contact its coordinators: Nicky Dent and Rebecca Brown (contacts): I promise that they will be extremely happy to hear from you…

Middle-upper arm circumference (MUAC) for nutritional surveillance in crisis-affected populations: development of a method

In Under-nutrition on April 30, 2012 at 3:43 pm

This is the PhD proposal of Séverine Frison (London School of Hygiene and Tropical Medicine). She undertakes her research together with Francesco Checchi and  Claudine Prudhon

Summary – Timely, sensitive, population-representative nutritional surveillance is crucial to detect nutritional emergencies in crisis-affected populations, and responding appropriately. Current approaches to nutritional surveillance mostly rely on regular anthropometric surveys, the results of which are interpreted alongside other crisis indicators such as mortality. However, there is little evidence on which to predicate the design of surveillance systems, and a variety of methods are employed in the field, with questionable impact, partly due to the infrequent nature of surveys.

Middle-upper arm circumference (MUAC) is known as a good predictor of mortality in children, and is increasingly adopted as the criterion for screening and admission to treatment programmes. Furthermore, MUAC is easier to measure than weight for height (WHZ), and may be more sensitive to changes in nutritional status. Despite this, it has not been used prominently in surveillance to date.

Here, we propose to develop a new method for nutritional surveillance in crisis-affected populations, based on measurement of the mean MUAC or the mean MUAC-for-age. Estimating the mean of these indices would entail lower sample size requirements than for prevalence surveys, improve the feasibility of data collection on the field, and allow for greater frequency and spatial resolution of surveillance. While mean MUAC trends could be interpreted separately, we wish here to study a potential method to infer GAM or SAM prevalence from the mean, thereby enabling quantification of programme needs. The proposed method is based on an assumption of normality and prior information about the population standard distribution of these indices, and relies on the ability of MUAC to capture oedema (kwashiorkor) cases. These assumptions need to be explored thoroughly.

The present project’s objectives are therefore to:

  1. Assemble a large dataset of surveys from a variety of settings that can be used to explore the statistical assumptions underlying the proposed method;
  2. Identify appropriate geographic strata into which to classify the surveys, and, more generally, regions of the world where nutritional surveys are undertaken, such that the variability of the SD of MUAC and MUAC-for-age within any given geographic stratum is minimised;
  3. Examine the association between MUAC or MUAC-for-age and oedema (as a sign of kwashiorkor), so as to investigate whether MUAC-based cut-offs for GAM or SAM capture oedema cases, and, if not, whether corrections can be applied to estimates based on MUAC alone in order to account for the prevalence of oedema;
  4. Examine the normality of MUAC and MUAC-for-age distributions at the population level and in small samples, and if necessary apply transformations to the data in order to achieve normality;
  5. Quantify and describe the SD of MUAC and MUAC-for-age across all surveys and within geographic strata, and assess how variability in SD would affect the precision of the proposed method;
  6. Investigate empirically the feasibility of using SDs of MUAC and MUAC-for-age from small sample size surveys directly by testing the stability of the SDs using a bootstrap method.
  7. Compare the appropriateness of MUAC versus MUAC-for-age cut-offs, by considering the degree of precision expected with either index if the proposed method is applied, as well as the relevance of either index for field operations.

We propose to accomplish the above objectives through extensive data analysis of at least 500 previously performed surveys from various areas of the world, livelihood zones and body shape strata. If successful, we envisage a second phase of development, consisting of defining sampling designs and sample size requirements for the proposed method to infer prevalence of GAM and SAM based on mean MUAC or MUAC-for-age.

The project will last 12 months, and is a collaboration between the London School of Hygiene and Tropical Medicine and the Health and Nutrition Tracking Service.

(Severine gave me the “green light” to publish this here)

 

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Prevalence of wasting among under 6-month-old infants in developing countries and implications of new case definitions using WHO growth standards: a secondary data analysis

In Under-nutrition on April 25, 2012 at 1:00 pm

Marko Kerac, Hannah Blencowe, Carlos Grijalva-Eternod, Marie McGrath, Jeremy Shoham, Tim J Cole, Andrew Seal

Arch Dis Child doi:10.1136/adc.2010.191882

“Objectives To determine wasting prevalence among infants aged under 6 months and describe the effects of new case definitions based on WHO growth standards. Design Secondary data analysis of demographic and health survey datasets. Setting 21 developing countries. Population 15 534 infants under 6 months and 147 694 children aged 6 to under 60 months (median 5072 individuals/country, range 1710–45 398). Wasting was defined as weight-for-height z-score <−2, moderate wasting as −3 to <−2 z-scores, severe wasting as z-score <−3. Results Using National Center for Health Statistics (NCHS) growth references, the nationwide prevalence of wasting in infant under-6-month ranges from 1.1% to 15% (median 3.7%, IQR 1.8–6.5%; ∼3 million wasted infants <6 months worldwide). Prevalence is more than doubled using WHO standards: 2.0–34% (median 15%, IQR 6.2–17%; ∼8.5 million wasted infants <6 months worldwide). Prevalence differences using WHO standards are more marked for infants under 6 months than children, with the greatest increase being for severe wasting (indicated by a regression line slope of 3.5 for infants <6 months vs 1.7 for children). Moderate infant-6-month wasting is also greater using WHO, whereas moderate child wasting is 0.9 times the NCHS prevalence. Conclusions Whether defined by NCHS references or WHO standards, wasting among infants under 6 months is prevalent in many of the developing countries examined in this study. Use of WHO standards to define wasting results in a greater disease burden, particularly for severe wasting. Policy makers, programme managers and clinicians in child health and nutrition programmes should consider resource and risk/benefit implications of changing case definitions.”

http://adc.bmj.com/content/early/2011/02/01/adc.2010.191882.full

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