GLOBAL: The vital statistics of hunger

Photo: Action contre la Faim

Aid workers and health officials measure a child's height and weight in western Chad

JOHANNESBURG, 4 July 2011 (IRIN) - Louise Masese-Mwirigi, an analyst recording nutrition data in southern Somalia with her team, have on occasion had to turn away from a village because the local authority that consented to the survey a week ago is no longer in charge or may have changed their minds when they arrive. Fighting between the government, its allies and various armed groups in parts of Somalia has severely restricted humanitarian space.

"The situation is uncertain in Somalia and access is a problem - especially in the last two years in central and southern Somalia," said Masese-Mwirigi, who works for the UN Food and Agriculture Organization's Food Security and Nutritional Analysis Unit (FSNAU) for Somalia. 

Armed with an electronic weighing scale and a metre-long board to measure the height of children, Masese-Mwirigi and her team, led by Mohamed Moalim, along with Action Contre la Faim (ACF), a food relief NGO, have carried out a survey in the Mogadishu region, where the capital is located. 

The survey is the first in seven years. "It took a month of planning… we could access six districts but had to let go of the remaining three because of security concerns." 

A rapid assessment by FSNAU in Mogadishu in December 2010 picked up high levels of malnutrition based on the measurement of the middle upper arm circumference (MUAC) - a quick, easy and cheap approximate measure of malnutrition in children younger than five years. "We felt we needed more information through a comprehensive nutrition survey, given the rains had performed poorly and the MUAC results were indicating high levels of malnutrition in the town." 

The MUAC measurement uses a long strip of plastic with a series of colour-bands that is put around a child's bare upper arm. The colours show the level of malnutrition: green indicates a 135mm circumference, which is normal; yellow - 125mm to 134mm - shows a risk of malnutrition; orange - 110mm-124mm means moderate malnutrition; red, for measurements less than 110mm, is an indication of severe malnutrition and risk of death. 

In the past two years FSNAU have had to depend entirely on MUAC in parts of the conflict-hit areas. "It is less resource-intensive, and quick and ideal for emergency situations, but ideally we would like a more thorough survey," Masese-Mwirigi said. 

Detailed data 

A thorough survey would take into account four variables - age, weight, height and gender - as well as the MUAC. Crude mortality rate (usually measured in deaths per 10,000 people per day in emergency situations), rate of disease prevalence, child care and feeding practices, household food security, and water and sanitation indicators, are also taken into account to understand the overall nutrition situation. 

When two of the anthropometric variables are used together they are called an index. Three indices are commonly used to assess the nutritional status of children: weight for age (WFA), height for age (HFA) and weight for height (WFH). 

These indices are then compared to a reference standard to get a sense of the severity and distribution of the nutritional problem in a country. 

The survey is the first in seven years. It took a month of planning… we could access six districts but had to let go of the remaining three because of security concerns

The WFA of a child compared to a reference population will tell if the child isnormal, overweight or underweight. HFA indicates whether the child's height is normal for his or her age. If the child is not as tall as expected then he or she is stunted, reflecting a long-term, chronic problem - stunting is a good indicator of chronic malnutrition. 

WFH is commonly used in acute emergencies to determine the scale of the crisis. It is often used when the child's age is not known, and in countries like Somalia, where hardly any public records of births and deaths exist. WFH is regarded as a good indicator of acute or short-term exposure to a negative environment, such as a drought, as it reflects recent weight loss or gain. WFH is a measure of acute malnutrition. 

Room for error 

With so many measurements involved there is always a lot of room for error. 

For instance a baby can often be not held properly to measure its length, or perhaps the child is not standing straight. Aid organisations are constantly trying to improve the skills of surveyors involved in taking measurements by organising training workshops periodically. 

Determining the correct age can also be problematic. "We use the calendar of events to accurately determine a child's age," explained Masese-Mwirigi. Events like major natural disasters or elections can indicate when a child was born. 

The other contentious issue in measuring malnutrition is what is considered average. The World Health Organization (WHO) provides a reference of growth standards, against which surveys calculate their deviations from the norm. 

Yet the WHO growth standards might not be the norm for a particular ethnic population that is naturally long-limbed, like Kenya's Maasai, or short-limbed, like the Gurkhas of Nepal. Even though the WHO standards were recently updated to better reflecthuman genetic diversity some experts feel country- or region-specific growth standards should be developed. 

Prominent experts like Mark Myatt, Senior Research Fellow at the Division of Epidemiology, of the Institute of Ophthalmology, University College, London, feel MUAC is a much more accurate measure. 

But that is not all. There are different scales of malnutrition. For individuals malnutrition can be moderate acute or severe acute. 

To work out levels of malnutrition, WFA, HFA and WFH measurements are used to calculate and classify using what is known as the "percentage of the median" and "Z-scores". 

For instance, in expressing the WFH as a "percentage of the median", a child's weight is divided by the average weight for a child of that height, as provided in the WHO growth standards, and then multiplied by 100 percent. Fortunately, there is computer software that does the calculation. 

The "Z-score" represents the difference between the observed weight and the median weight of the reference population, expressed in standard deviation units. When the percentage of the median is less than 70 percent, and the Z-score is less than -3, or oedema is present, the child is said to be suffering from severe acute malnutrition. 

GAM or SAM? 

Populations are described as severe acute or global acute. "Global acute malnutrition (GAM) refers to the total cases of moderate acute and severe acute malnutrition (SAM) in a population," Médecins Sans Frontières (MSF), the medical NGO, notes in their useful manual, A Beginner's Guide to Malnutrition. 

GAM is calculated with the Z-score defined as a weight-for-height index less than -2 standard deviations from the mean weight of a reference population of children of the same height. 

A GAM value of more than 10 percent generally identifies an emergency. Commonly used thresholds for GAM are less than five percent (acceptable), between five and just under 10 percent (poor), between 10 percent and under 15 percent (serious), while anything more is critical. 

Clinical signs such as bilateral oedema - swelling in the feet, legs or face caused by an extreme shortage of protein - are a separate indicator of severe malnutrition in children. 

"We recorded a GAM rate of 15.2 percent for Mogadishu in our survey," said Masese-Mwirigi. In Somalia the FSNAU has been recording GAM rates of 15 percent and above for a long time, GAM rates of over 15- 20 percent indicate a critical nutrition situation, while rates over 20 percent are seen as very critical. The GAM rates reported in Mogadishu town are high, also given that there are a large number of feeding interventions in the town. 

Prices of the staple grains - maize and sorghum - have gone up by between 52 and 95 percent in most markets. FSNAU reports that in some areas prices have doubled and even tripled since 2010. 

In 2011 the major rainy season began late and was poorly distributed across time and place in southern Somalia - the second bad season consecutively, as the first harvests in January failed. 

A smaller cereals harvest, low stocks and poor access because of continued conflict to Bakara, the main market in Mogadishu, have made basic foodstuffs harder to get and more expensive.