Some statistical considerations on the use of anthropometry to assess nutritional status.

Anthropometry (the use of body measurements to assess nutritional status) is a practical and immediately applicable technique for assessing children's development patterns during the first years of life. An evaluation of their growth also provides useful insights into the nutrition and health situation of entire population groups. Anthropometric indicators are less accurate than clinical and biochemical techniques when it comes to assessing individual nutritional status. In many field situations where resources are severely limited, however, anthropometry can be used as a screening device to identify individuals at risk of undernutrition, followed by a more elaborate investigation using other techniques. Similarly, growth monitoring permits the detection of individuals with faltering growth, who can then be appropriately referred to specialized care. Thanks to the standardization that has taken place in recent years, changes in trends over time with respect to the nutritional situation can be evaluated in countries where national food and nutrition surveillance systems have been developed, or where nationally representative cross-sectional surveys have been conducted some years apart using identical, or nearly identical, methodologies. Although data that can be used to evaluate trends are limited, some insight can be gained into the nutritional situation and changes occurring over time in a number of countries. Prevalence figures for underweight (low weight-for-age) have been prepared using standard methods of data collection, analysis and presentation, for several countries in Africa, the Americas and Asia. As such, they fail to differentiate between wasting and stunting, or to evaluate differences between age groups. Also, they do not necessarily reflect trends in other countries in the same or other regions. Still, it is interesting, if not statistically significant, that there has been a general improvement in the nutritional status of preschool children. Intercountry trend comparisons are difficult for two main reasons. Firstly, the time between surveys is occasionally different and, secondly, despite efforts to standardize data analysis and presentation, different cut-off points have been used to calculate prevalence figures and estimate the extent of undernutrition. However, the use of identical cut-off points is not essential for making intercountry trend analyses since it is the general trends in growth deficit and nutritional status over time which are being evaluated.(ABSTRACT TRUNCATED AT 400 WORDS)