II-c. Growth Measurement
Different kinds of malnutrition have different kinds of manifestations. Because of its worldwide importance, the remainder of this tutorial focuses on protein-energy malnutrition. However, the perspectives developed can easily be adapted to other forms of malnutrition or, indeed, to other kinds of concerns such as inadequate water supplies, sanitation issues, housing issues, etc.
Assessments of PEM nutrition status are commonly based on anthropometric (body) measures. Measurements may be made of height, weight, or arm circumference, for example, and the results compared with appropriate norms. For a time the Gomez scale of expected weight (or height) for age was used. The extent of malnutrition was assessed in terms of the ratio of a child's weight to the expected weight for healthy children of the same age and gender, expressed as a percentage. Thus a child between 60 % and 75 % of the standard weight for his or her age would be said to be moderately malnourished. The preference now is to make the assessment in terms of the number of statistical "standard deviations" below the expected weight (or height). A child more than two standard deviations below the standard is described as undernourished.
In adults, assessment are made in terms of the Body Mass Index. BMI is calculated as the individual's weight in kilograms divided by the square of the individual's height in meters. Adults whose BMI is under 18.5 are much too thin, and thus are diagnosed as being chronically undernourished .
UNICEF points out that "most malnutrition is not caused by shortages of food in the house" and that "most feeding programmes fail to have any significant effect on children's nutritional status (Grant, 1987, p. 65)." One review of the effects of feeding programs on the growth of children showed that overall "anthropometric improvement was surprisingly small (Beaton 1982)." As the authors speculate, part of the reason may have been that there is often considerable leakage of food away from the targeted individuals, with the result that their dietary intake actually did not improve very much. However, a more fundamental reason may have been that food supply was not really a major problem to begin with, and the observed growth retardation could have been addressed more effectively with other kinds of programs, perhaps emphasizing immunizations or sanitation or improved child care. The feeding programs may have not only reached the wrong individuals, but may have been altogether the wrong choice of remedy.
Anthropometric measures do not assess nutrition status directly; they assess developmental impairment or growth failure, the most extensive public health problem among children in developing countries. It results from the complex interaction of nutritional, biological, and social factors. Rates of physical growth and achieved body size have been accepted as markers of this syndrome. Growth failure may be partly due to dietary adequacy, but there can be other causes as well.
Different forms of growth failure can be described in these terms:
� underweight or overweight, for deviations of body weight from expected weight-for-age;
� wasted or obese, for deviations of body weight from expected weight-for-height; or
� stunted, for deviations of height below expected height for age.
Growth retardation in the forms of wasting, stunting, and underweight are usually signs of malnutrition, but there are exceptional cases in which they result from other causes. Thus children who show growth retardation should be clinically examined to characterize their conditions more precisely. For our purposes, however, the degree of growth retardation can be taken as a reasonable indicator of the extent of malnutrition.
If the objective is to identify individual children in need of attention, it is most useful to assess the extent to which children are wasted, that is, the extent to which they have low weight for their height. Many children who are underweight, who have low weight for their age may have "scars" of past malnutrition, and not signs of current problems ("wounds"). Stunting, in which children are short for their age, is due more to past than to current problems.
Growth failure is most active between six and 24 months of age, which is thus the main "window of opportunity" for prevention. Actions targeted to children beyond two years of age will not be very useful in reversing their growth retardation because their low weight or height is likely to have originated in their first two years of life.
This has important implications for public policy. Some nutrition programs concerned with protein-energy malnutrition as indicated by low weight or low height may be misdirected in terms of their intended coverage. School lunch, programs, for example, are not likely to be of much use for reversing growth retardation. Rather than selectively targeting underweight or underheight individuals among older children, it may be more efficient and effective to focus the resources on all children up to two years of age. This conforms with findings that public expenditure on children generally yields far better results when focused on very small children (Carnegie 1994).
Continue to II-d. Numbers of People Malnourished
Subsection II-c last updated on September 26, 1999