A Role for the Knemometer in Emergencies

Summary of research study

During emergencies, there is usually more concern about the effect of malnutrition in children, on weight loss rather than on linear growth, i.e. skeletal bone growth. However, some recent work using a little known instrument called the 'Knemometer' could start to get us thinking more about possible roles for measuring skeletal growth in malnourished children during emergency programmes.

In the best of circumstances it is not possible to estimate linear growth accurately from total length or height over less than a 3 month period. However, the Knemometer can measure changes in knee-heel length over much shorter periods. The instrument is fairly cheap (approximately £1,600), robust and easily portable.

A recent study using the knemometer in two therapeutic feeding centres run by ACF in Bo, Sierra Leone, set out to answer the question 'were children just gaining soft tissue more quickly, or was linear growth, i.e. bone growth, also accelerated?' All the children in the study were being fed the new "therapeutic milk" (F100) and had their knee-heel length measured weekly. Children gained on average 10 gms/kg body weight/day until discharge. The main findings of the study were:

• rates of knee-heel length increase were similar to healthy children of the same age and were not affected by the degree of stunting
• marasmic children started gaining knee-heel length immediately but there was a delay in severely malnourished oedematous children, even after they had lost their oedema
• similar studies need to be repeated on other diets in other settings.

So, might this relatively new device for measuring skeletal growth have a greater role in emergency settings in the future? Well, while most people seem to anticipate some application of the knemometer in emergency work, there are different opinions as to the form this might take. One view is that the instrument's main use will be to compare the efficiency of different foods in therapeutic and supplementary feeding programmes in promoting skeletal growth. Another view is that the knemometer could eventually have more of an individual monitoring role in selective feeding programmes to ensure that individuals are only discharged when appropriate skeletal growth has occurred. The reasoning here is that weight gain in malnourished children comprises deposition of fatty tissue, muscle and, skeletal growth. If children are discharged from feeding centres when there has been weight gain but little skeletal growth, then recovery may be less sustainable as fatty tissue can so easily be lost again. This may be particularly relevant to situations where individuals are discharged to a food insecure environment.

It seems clear that in emergencies we need to concern ourselves more about the effect of malnutrition on skeletal growth and eventual stunting and that the knemometer may be a tool to help us in this respect. Stunting is, after all, strongly associated with lower IQs in adults, impaired physical ability and the risk of having low birth weight children.

Further information on this study can be obtained from: Barbara Golden, Department of Medicine and Therapeutics, University of Aberdeen, Forresterhill AB9 2ZD, Tel No 44 1224 681 818. E-mail b.e.golden@abdn.ac.uk.