the nutritional status of - Health Systems Trust

RESULTS
CHAPTER 3
3.1 ANTHROPOMETRY
3.1.1 INTRODUCTION
In this section, reported anthropometric measurements and indices of South Africans, stratified for age, gender and
ethnic group, are used as indicators to evaluate nutritional status of specific groups. Anthropometric measurements
are used to assess body size, proportions and composition. They reflect inadequate or excess food intake, insufficient
exercise, growth of children, disease, and overall health and welfare. Because anthropometry is the single most
portable, universally applicable, inexpensive and non-invasive method to obtain information on nutritional status
(De Onis & Habicht, 1996), it is often used to evaluate the outcomes of policies and nutrition intervention programmes,
or to select individuals whom should be targeted in such programmes. Therefore, repeated cross-sectional or
longitudinal measurements of anthropometry will monitor changes in nutritional indicators over time, giving
warning of impending crises and identify at risk populations.
3.1.2 DEFINITIONS AND TERMINOLOGY
The definitions of different concepts and the terminology used in this section are in agreement with recent
recommendations of an expert committee on the use and interpretation of anthropometry of the World Health
Organisation (WHO, 1995).
3.1.2.1 Measurements
The basic nutritional anthropometric measurements are weight (mass), height, body circumferences (waist, hip,
head and upper arm), as well as skinfolds.
3.1.2.2 Indices
These are combinations of measurements necessary for interpretation of the measurements. Examples are body
mass index [weight (kg)/height (m 2 )], weight-for-age (W-a), height-for-age (H-a) or weight-for-height (W-H). The
indices can be expressed in terms of Z-scores, percentiles or percent of median. These expressions can be used to
compare an individual or a group with a reference population.
* Z-scores:
This is a standard deviation score and is defined by WHO (1995) as the “deviation of the value for an individual from
the median value of the reference population, divided by the standard deviation for the reference population”.
Therefore: Z-score =
(observed value) - (median reference value)
standard deviation of reference population
* Percentiles
This is the rank position of an individual on a given reference distribution, stated in terms of what percentage of the
group is equalled or exceeded by the individual. Therefore, a child of a specific age, whose weight falls in the 10th
percentile, weighs the same or more than 10 % of the reference population of children of the same age.
* Percent of median
This is the ratio of a measured value in an individual such as weight or height to the median value of the reference
data for the same age, expressed as a percentage.
2.1.2.3 Indicators
These are applications of indices to evaluate nutritional status. In this analysis, the percentage of children below a
defined cutpoint (level) for a particular index (W-a, H-a, W-H), was used to evaluate the extent and magnitude of
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