Biomedical subjects
J Gorstein
Publications and source records attributed to J Gorstein.
Assessment of nutritional status: effects of different methods to determine age on the classification of undernutrition.
The evaluation of nutritional status using anthropometry has been widely employed in field studies and nutritional surveillance programmes. Two of the primary indicators used, weight-for-age and height-for-age, require accurate age information for proper assessments to be made. Three data sets on nutritional status were evaluated using different methods to determine age: rounding to the most recently attained month, rounding to the nearest whole month, and ages computed from birth dates and visit dates. The impact of these different methods on the classification of nutritional status were found to be dramatic, especially in infants during the first year of life. In some cases, when ages are rounded to the most recently attained month, as few as 43% of the children classified as malnourished based on the indicator, height-for-age, and the cut-off point, less than -2 Standard Deviations from the reference median, are identified relative to when ages are computed from birth and visit dates. Beyond the discrepancies in estimating prevalence below specific cut-off points to designate undernutrition, the use of the different methods also affects entire distributions. The problem of using different methods to estimate age, and the impact they have on the classification of undernutrition are of critical public health importance, especially when this information is used to identify individuals and groups as well as for planning and policy development.
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)
The global prevalence of obesity--an initial overview of available data.
Methods of measuring obesity are briefly reviewed. The more precise methods of measuring the body-fat mass are too complex and expensive for use in regular public health practice or individual screening. Anthropometry can, however, provide useful information. Two anthropometric indicators of obesity or overweight are recommended for classifying obesity. For adults, the body-mass index is reasonably easy to obtain and correlates well with mortality and morbidity risk. For children, "overweight" is indicated by a weight-for-height above the median NCHS value plus two standard deviations. Data compiled by the WHO Nutrition Unit, using these two indicators, are presented for a number of countries worldwide in Table 1 & Fig. 1.