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Letters to the Editor Indian Pediatrics 2001; 38: 1061-1064 |
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A Novel Growth Assessment Chart for Adolescents |
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G rowth assessment among adolescents has come to limelight as IAP has promised to look after them. The physical growth of adolescents especially that of girls has now been identified as one of the key determinants of future low birth weight (LBW) babies. A pre-pregnancy weight of about 45 kg and height of 145 cm has been agreed upon as desirable. For growth assessment among adolescents, we are using various tools like separate age specific charts for boys and girls (NNNB data), body mass index (BMI) for age-percentile charts for boys and girls (NCHS data) and so on. But, it is confusing to use different charts in a single health card for adolescents. It is also time consuming and elaborate to measure weight and height and then calculate BMI for each child and plot on the graph.Moreover, adolescent growth is linked to the onset of puberty and various genetic, hormonal and nutritional factors. The early growing and the late maturing adolsescents included in a particular age group tend to level off the growth peak and camouflage the issue. It appears as though the adolescent children grow more gradually and over a long period than they do. Thus the normal variation in timing of growth spurt and puberty can lead to misdiagnosis of growth disorder. The stature of parents is yet another issue to be considered in this respect. Hence, the existing age specific charts prove to be insufficient due to the various reasons mentioned above. This is the case with adults too. Incorporating weight, height and BMI in the same chart seems to address all these issues and the concept of appropriate body proportions. Conventionally, BMI >18.5 is considered normal, >25 as tendency for obesity (overweight) and >30 as overt obesity(1,2). But, many studies have shown that BMI <18.5 as the cut off indicator of chronic energy deficiency (CED) is inappropriate(2,3) and only 6% of the adolescents had BMI >18.5(4). By using this cut off, one would include far too many normal children as undernourished(5,6). Literature scan reveals that workers have suggested <15 as the cut off to denote underweight or borderline CED in growing children(7,8) and <13 as severe CED(8). In late teens and adults when growth spurt is over, the conventional lower and upper cut off values of 18.5 and 25 seem appropriate. Considering the above facts, a novel growth assessment chart, the ‘ELIZ health path for adolescents and adults (EHPA)’ was designed and validated(9). This is depicted in Fig. 1. The same chart can be used for both sexes. One has to measure the height and weight and plot the height on the X axis and weight on the Y axis and then directly read the BMI from the right margin. In EHPA, the bold line denoting the ideal was drawn as follows; for those in the growing age or up to a height of 150 cm, i.e., corresponding to an age of 12-13 years when growth is still possible, the lower and upper cut off values selected are 15 and 22 respectively and for those who have completed growth or height >150 cm, the cut offs are 18.5 and 25 as per the existing norms. A preliminary validation of the chart on 500 adolescent boys and girls brought out some interesting results. Among the 13-19 year old teenagers, the weight ranged between 24-78 kg and the height between 130-182 cm and all the values were within the purview of the chart; 79% of them were within the bold lines of the normal health path, 11% were underweight with borderline CED and <1% had severe CED. Ten per cent of them were overweight and <1% had overt obesity. Re-analysis using the existing norm of 18.5 as cut off showed that far too many, up to 67% of them had to be labeled as underweight or chronically energy deficient. As suggested by previous studies, this is unacceptable and unrealistic. Many of them were still in the growth spurt and were likely to become normal by the time they complete their growth. The prevalence of obesity is now reported to be on the increase and various studies from affluent countries have shown an increase from 5% to 10% over a decade(10). Sensitiz-ing the health workers and community to the problem of obesity is also attempted in the present chart. The concept of age and sex independence projected in this chart has been evaluated on the light of the International Obesity Task Force (IOTF) recommendations based on 6 large international cross sectional growth studies from Brazil, Great Britain, Hong Kong, Netherlands, Singapore and United States(2). The review showed that at birth, the median BMI is as low as 13, increases to 15.5 at age 6 and then increases to 21 by age 20. The mild differences in sex are not highlighted. The existing centiles of age and sex as cut off points to denote overweight and obesity among adults have been revised to BMI 25 corresponding to 90th centile for overweight and BMI 30 corresponding to 97th centile for obesity. The international cut off points for overweight and obesity by sex between 2-18 years that pass through BMI of 25 and 30 at age 18 have been defined and that showed only minor differences in decimals between boys and girls(2). The cut off indicators suggested for overweight and obesity up to the age of 12-13 years was around 22 and 25 respectively as selected in the present chart. BMI 18.5 corresponding to 12th centile to denote underweight or CED also has been reviewed and a possible suggestion of 17 has been given, but many Indian workers have already suggested 15(3,7,8). Thus the use of the present chart for both sexes and the lower and the higher cut off indicators selected are appropriate for a preliminary screening of large number of children and adolescents in the community setting. For detailed evaluation of an individual child, the centile chart and age and sex specific data are recommended. The advantages of the present chart are the following: (i) It is very simple to use and demonstrate. The weight and height can be plotted in the same chart and BMI can be directly read from the right margin of the chart. It avoids the tedious calculation of BMI; (ii) The same chart can be used for both sexes; (iii) In addition to incorporating weight, height and BMI in the same chart, it also depicts the various curves denoting normal range, underweight or CED, overweight (tendency for obesity) and obesity; (iv) It can diagnose both underweight and obesity and also shows the desirable weight range for the stature of an individual. This information may help to curtail future obesity as well as purposeful dieting and slimming especially in adolescent girls, who consider themselves obese, even though they are in the normal range; (v) The purposeful ommission of a curve below BMI 15, for example, at BMI 13, will avoid false satisfaction among underweight adolescents that they are also above a curve. This is important because adolescence is the last and the final chance for them to grow and maintain normal body proportions; and (iv) This health path can also be used by adults to maintain optimum body proportions and thus remain fit and keep away from many of the lifestyle diseases.
Fig. 1. The chart is applicable to both sexes. Plot the height on the X axis and the weight on the Y axis and then directly read the BMI from the right margin. For example, if the height is 160 cm and weight is 55 kg, BMI is 22 and if the height is 160 cm and weight id 60 kg, BMI is between 22 and 25. Readings between the bold lines is ideal. For those in the growing age group or up to a height of 150 cm, readings of BMI <15 indicates underweight or chronic energy deficiency (CED) and readings >22 indicate overweight and >25 indicates obesity. For those who have completed growth or above a height of 150 cm, readings of BMI <18.5 indicate underweight or chronic energy deficiency (CED) and readings >25 indicate overweight and >30 indicate obesity.
K.E. Elizabeth,
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