|Refugee Nutrition Information System (RNIS), No. 35 - Report on the Nutrition Situation of Refugees and Displaced Populations (UNSSCN, 2001, 70 p.)|
WASTING is defined <-2S Z scores wt/ht, or sometimes <80%, wt/ht by NCHS standards, usually in children of 6-59 months. For guidance in interpretation, prevalences of around 5-10% are usual in African populations in nondrought periods. A prevalence > 10% is considered an alert and a prevalence of over 15% is considered serious. A 20% prevalence of wasting is undoubtedly high, although these figures should be interpreted with the context.
SEVERE WASTING can be defined as below -3SDs (or about 70%). Any significant prevalence of severe wasting is unusual and indicates heightened risk. (When wasting and severe wasting are reported in the text, wasting includes severe - e.g. total percent less than -2SDs, not percent between -2SDs and -3SDs.)
STUNTING is defined as less than -2SDs height-for-age by NCHS standards, usually in children aged 6-59 months.
SEVERE STUNTING is defined as less than -3SDs height-for-age by NCHS standards, usually in children aged 6-59 months. (When stunting and severe stunting are reported in the text, stunting includes severe - e.g. total percent less than -2SDs, not percent between -2SDs and -3SDs.)
BMI (wt/ht2) is a measure of chronic undernutrition in adults. We have taken BMI<18.5 as an indication of mild chronic undernutrition, and BMI<16 as an indication of severe chronic undernutrition in adults aged less than 60 years (WHO, 1995). The BMI of different populations should not be compared without standardising for body shape. (See July 2000 RNIS supplement on measuring adult nutritional status).
MUAC (cm) is a measure of energy deficiency in both adults and children. In children, equivalent cut-offs to -2SDs and -3SDs of wt/ht for arm circumference are about 12.0 to 12.5 cms, and 11.0 to 11.5 cms. In adults, MUAC<22 cm in women and <23 cm in men may be indicative of a poor nutritional status. BMI and MUAC are sometimes used in conjunction to classify adult nutritional status (James et al, 1994). Acute adult undernutrition may be diagnosed using MUAC. A MUAC<18.5 may be indicative of acute undernutrition and MUAC<16 of severe acute malnutrition. (See July 2000 RNIS supplement on measuring adult nutritional status).
OEDEMA is the key clinical sign of kwashiorkor, a severe form of protein-energy malnutrition, carrying a very high mortality risk in young children. It should be diagnosed as pitting oedema, usually on the upper surface of the foot. Where oedema is noted in the text, it means kwashiorkor. Any prevalence detected is cause for concern.
ACUTE MALNUTRITION is the prevalence of wasting (Weight for Height) <-2 Z scores and/or oedema.
CHRONIC MALNUTRITION is the prevalence of stunting (Height for age)
A CRUDE MORTALITY RATE in a normal population in a developed or developing country is around 10/1,000/year which is equivalent to 0.27/10,000/day (or 8/10,000/month). Mortality rates are given here as times normal, i.e. as multiple of 0.27/10,000/day. [CDC has proposed that above 1/10,000/day is a very serious situation and above 2/10,000/day is an emergency out of control.] Under-five mortality rates (U5MR) are increasingly reported. The average U5MR for Sub-Saharan Africa is 175/1,000 live births, equivalent to 1.4/10,000 children/day and for South Asia the U5MR is 0.7/10,000/day (in 1995, see UNICEF, 1997, p.98).
FOOD DISTRIBUTED is usually estimated as dietary energy made available, as an average figure in kcals/person/day. This divides the total food energy distributed by population irrespective of age/gender (kcals being derived from known composition of foods); note that this population estimate is often very uncertain. The adequacy of this average figure can be roughly assessed by comparison with the calculated average requirement for the population (although this ignores maldistribution), itself determined by four parameters: demographic composition, activity level to be supported, body weights of the population, and environmental temperature; an allowance for regaining body weight lost by prior malnutrition is sometimes included (see Schofield and Mason 1994 for more on this subject). For a healthy population with a demographic composition typical of Africa, under normal nutritional conditions, and environmental temperature of 20°C, the average requirement is estimated as 1,950-2,210 kcals/person/day for light activity (1.55 BMR). Raised mortality is observed to be associated with kcal availability of less than 1,500 kcals/person/day (ACC/SCN, 1994, p81).
INDICATORS AND CUT-OFFS INDICATING SERIOUS PROBLEMS are levels of wasting above 20%, crude mortality rates in excess of 1/10,000/day (about four times normal - especially if still rising), and/or significant levels of micronutrient deficiency disease. Food rations significantly less than the average requirements as described above for a population wholly dependent on food aid would also indicate an emergency.