WASTING is defined as less than -2SDs, 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 non-drought periods. We have taken more than 20% prevalence of wasting as undoubtedly high and indicating a serious situation; more than 40% is a severe crisis. 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.) Data from 1993/4 shows that the most efficient predictor of elevated mortality is a cut off of 15% wasting (ACC/SCN, 1994, p81). 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, depending on age. BMI (wt/ht2) is a measure of energy deficiency in adults. We have taken BMI<18.5 as an indication of mild energy deficiency, and BMI<16 as an indication of severe energy deficiency (WHO, 1995).
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.
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. Formulae and software given by James and Schofield (1990) allow calculation by these parameters, and results (Schofield and Mason, 1994) provide some guidance for interpreting adequacy of rations reported here. For a healthy population with a demographic composition typical of Africa, under normal nutritional conditions, and environmental temperature of 20oC, 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 1500 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.
James W.P.T. and Schofield C. (1990) Human Energy Requirements. FAO/OUP.
Schofield C. and Mason J. (1994) Evaluating Energy Adequacy of Rations Provided to Refugees and Displaced Persons. Paper prepared for Workshop on the Improvement of the Nutrition of Refugees and Displaced People in Africa, Machakos, Kenya, 5-7 December 1994. ACC/SCN, Geneva.
ACC/SCN (1994) Update on the Nutrition Situation, 1994 (p81).
UNICEF (1997) State of the World's Children p.98. UNICEF, New York.
WHO (1995) Bulletin of the World Health Organization,
1995, 73 (5): 673-680.