The introduction of new standards to assess nutrition in children could lead to confusion and a cut in the numbers of malnourished children eligible for emergency feeding programs, warn researchers in this week's BMJ.
According to the UN World Food Program, the number of nutritional emergencies has risen over the last twenty years, from an average of 15 per year during the 1980s to more than 30 per year since 2000. In 2005, around 73 million people were supplied with food aid.
The new World Health Organization standards were released in April 2006 and are being advocated as a replacement for the currently used growth reference curves, produced by the National Center for Health Statistics (NCHS) and WHO in 1978.
But research from Andrew Seal and Marko Kerac at University College London and the College of Medicine, Malawi, found that, whilst the new standards would increase the number of children identified as malnourished, it could also result in fewer children being admitted to feeding programs.
The reason for this is the way nutritional status is calculated. It can be expressed by using either z scores or the percentage of the median. Most aid agencies use the median method to determine a child's eligibility for admission on to a therapeutic feeding program although the z score method is also used infrequently for this purpose.
The research team used both methods and found marked differences between the cut-offs used for defining severe acute malnutrition from the WHO standards and NCHS reference data.
Under the z score calculation, children were more likely to be diagnosed as severely malnourished, but under the median method calculation, children were less likely to be diagnosed as malnourished. This means that fewer children would be eligible for therapeutic feeding programs and those already on programs would be discharged sooner than at present.
A similar pattern emerged in the diagnosis of severe and moderate malnutrition.
The authors say the potential impact on mortality rates of the inappropriate use of the WHO Growth standards is, as yet, unknown. They suggest that a full assessment of the appropriate use of the new WHO standards is urgently required and should be completed before they are implemented by aid agencies running emergency nutrition programs.