The Use of Body-Mass Index as A Measurement of Body Fat - Article Example

THE USE OF BODY-MASS INDEX AS A MEASUREMENT OF BODY FAT ABSTRACT The use of body mass index as a method for the measurement and evaluation of body fat is evaluated. Using meta-analysis of the available literature and programs employed to initiate such efforts, the uses and limitations of the technique are described. Alternatives to body mass index are evaluated, described, based upon their comparative utility. A conclusion is supported that different methods of body fat measurement are efficient for various purposes, however for the purposes of large scale screening of a population for likelihood of obesity, body mass index is an efficient means by which obesity can be determined in the interest of health and fitness. INTRODUCTION In an academic setting, the measurement of Body-Mass Index has become a topic of particular concern. School is where children first come into contact with civil/national authority, and thus it is in the interest of that authority to explore this, and other strategies in the interest of promoting public welfare. with upwards of 90% of youth in the developed world (95%) enrolled in public school, (U.S. Department of Commerce, 2005) The schools become the obvious battleground for health concerns, such as BMI and the risk for obesity. The interest with respect to public welfare comes in the form of obesity control and prevention. In developed countries, particularly the United States, concern has risen to the point where the terms 'Obesity' and 'Epidemic' are used in close association. Much data is available on the assorted health risks, both mental as well as the obvious physical concerns. Among them being diabetes risks, depression, and various heart/cardiovascular pathologies resulting from increased demand on the circulatory system. It is worthwhile to clarify a definition for obesity and the commensurate dangers thereof. Obesity is in essence the condition of possessing excess body fat beyond that which is necessary for optimal health and mobility. The dangers of obesity, in addition to the aforementioned diabetic risk, are one factor, but other concerns as well. High blood pressure, insomnia/sleep apnea, and orthopedic concerns are a problem, in addition to increases in cholesterol that may trigger heart problems. (Schonfeld-Warden & Warden, 1997) Depression, and other mental health consequences are also possible. (Schwartz, 2003) This analysis was conducted to determine whether the preeminence of body mass index as a method for the evaluation of total body fat is justified, and whether viable alternatives exist. LITERATURE REVIEW For Body-Mass Index, it can be summarized as a calculation of an individual's weight, as measured in kilograms, divided by the square of their height as measured in meters. This allows for a standardization of height based on weight, allowing a tool of comparison between different individuals. Thus it is possible to qualify different individuals as obese or not, based on an estimation of this index. This allows specified categories of obese, or overweight, or normal. However, it is arguable that BMI is not a direct measure of body fat, the crux of the concern. It is understood that the body mass index will increase with rising body fat, although the measurement is not a precise correlation. With differences in height, and subtle variations in the distribution of fat, a presumptive calculation has been deemed sufficient by some experts as a means to determine obesity. (Weight/Height in Meters-squared) BMI is intended as a general tool to identify and correct potentially worrisome population trends affecting the health of children. Moreover, the threat of obesity among the young also trends towards a risk of adult obesity. (Serdula et al. 1993) And in fact, among children under the age of 18, both with respect to prepubescent children and teenagers, incidence of obesity have increased by over 300% since 1980. (Hedley et al. 2004), (Ogden et al. 2004) More directed measures by which a body that can be quantified, such as densitometry or various means to measure bioelectrical resistance or presence of impediments, but highly directed measures would require extensive clinical analysis that would be deemed in efficient for wide scale population deployment. As a result, body mass index as an indicator of a likely obesity problem has been adopted by many experts, as a means of identifying trends of obesity related pathologies. (National Heart Foundation, 2007) Body mass index analysis can serve as an important screening tool. It allows for the presumptive identification of individuals that exhibit a higher probability of the pathology in question, in this instance illuminating individuals who are likely to be healthy from consideration. This allows for the optimization of resources and time for those truly in need. But by itself, body mass index should not be utilized as a definitive diagnostic tool. Rather a means by which to identify individuals for whom more concern and attention is warranted. Thus it becomes possible to determine an individual's weight status, through the comparison of body mass index to similar individuals of a closely aligned age group and sex. Age of course, must be taken into account due to natural growth processes – especially among adolescents. Including the measurement of age allows the ability to distinguish weight problems with a greater standard of specificity than if height and actual weight alone were the only criteria. METHODOLOGY The methods used in this study include conclusions from literature, as well as descriptions of the instrumentation commonly employed. Typical methods would use a scale and ruler in order to measure height, many public schools are equipped with such devices, as well as doctor’s offices. Alternative methods for estimating body fat would involve calipers, pinching the flesh of an individual in order to measure adipose tissue beneath the skin. This method is evaluated and compared with body mass index. There are also in depth clinical scans that can give precise measurements, but these are not utilized as early screening methods. Once the determination of body mass index has been ascertained mathematically, it can then be chartered on a developmental chart tailored to the individuals’ age and cohort. At which point, the individual can be scored with a percentile ranking, whether higher or lower than the corresponding index for individuals of that age and sex. For example, a 13 year old boy in the 11th percentile has a higher body mass index than 11/100 boys of the same age. Conversely, a 10-year-old girl in the 80th percentile has a higher body mass index than 80/100 similar girls in her age group. Among children, the standard classifications are as follows: Obese - the child is obese with a body mass index equal to or above the 95th percentile for their age group. Overweight – if the child has a body mass index above the 85th percentile but not yet equal to the 95th percentile they are overweight. Normal – would be a body mass index below the 85th percentile, yet still above the 5th percentile. Underweight – is applicable for all children with a body mass index below the 5th percentile for their age grouping. (AMA, 2007) It is widely accepted that individuals classified as overweight or obese experience a range of health problems discussed above, but for adults there are alternative measurement formulas that can be applied. Among Caucasian adults over the age of 18 the four categories can be assigned with respect to calculated thresholds, the distinction being rather a lack of distinction between men and women in adulthood. Specifically, after the individuals weight in kilograms is divided by their meters of height squared the four categories can be assigned without the use of percentiles. The individual is underweight if they are found to be below 18.5 for their index. A normal or healthy weight is indicated by a body mass index between 18.5 and 24.9. Anything above 25 is at minimum overweight. Whereas a body mass index equal to or above the 30 qualifies as obese for adults. In the case of adults, age is generally unimportant as a determining factor with respect to the probability of obesity. (National Obesity Observatory, 2009) Measurements: African American Male: Adult = 1.8 meters, 70 kilograms, BMI: 20.68 = Normal Weight Caucasian male: Child = 1.3 meters, 50 kilograms, BMI: 27.85 = Over Weight Caucasian female: Adult = 1.5 meters, 46 kilograms, BMI: 19.40 = Normal Weight Hispanic male: Child = 1.32 meters, 61 kilograms, BMI: 32.98 = Obese RESULTS Body mass index has limitations, but is the standard employed for prescreening of obese adults and children. This is supported by direct experience as well as the balance of literature pertaining to the topic. The definition of BMI in this study corresponds to the standard equation, described below: _ BMI = weight (kg) (height (m))2 Below is an illustration of standardized heights/weights for boys with indicators of percentile categories: Nihiser, 2010. DISCUSSION & CONCLUSION There are certain drawbacks with the application of body mass index as an indicator of fitness and fatness. In the case of children, nearness to puberty, as well as a healthy level of physical fitness by which muscle mass is increased may yield abnormal results. An individual heavy due to muscular development could exhibit a higher weight for their height compared with children their age or adults. Thus, with these limitations body mass index serves primarily as a screening mechanism rather than a definitive indicator. There is also the possibility of different ethnic groups distributing body fat in different proportions, independent of height or age. Some populations, such as the natives of New Guinea and Africa's Kalahari Desert may have significant differences in their risks of blood pressure and body fat distribution, to name two examples.(Kaminer & Lutz, 1960), (Whyte, 1958) But it is likely that body mass indices will be popular for screening large numbers of people in the foreseeable future. But in light of the possible limitations it is essential for decision-makers to remain clear-headed with respect to a cost-benefit analysis before large-scale BMI testing is undertaken. A school must consider: Is their environment safe and supportive for children of all likely weight-categories? If not, there is the prospect of adding additional basis for criticism or bullying. Furthermore, the paramount consideration prior to the implementation of a body mass index evaluation programs is whether a support structure exists to assist those children that are outside of healthy categories. Otherwise, there is little value in pursuing such an initiative as a means of evaluating body fat. The school must consider whether it has the willingness to adopt a weight-healthy curriculum intended to counteract harmful social pressures on either side of the BMI spectrum, which would include measures against overeating and improper nutrition, as well as anorexic tendencies on the opposite end. The school must determine whether it is capable of implementing zero tolerance for any kind of weight discrimination or bullying as a consequence, which then has the potential to promote anorexia. In addition, is the teaching staff able to provide counseling for students that have weight-related issues, as well as supplemental instruction for the parents in order to support a healthy body image for their children? The staff members engaged in any form of direct measurement must be appropriately evaluated to ensure professionalism and competency in regards to this procedure. Some form of certification or verification would be desirable to ensure an accurate standard for the measurement of the body mass of the children. Superior results can be achieved with measurements that are as close to actual reality as possible, while maintaining consistency throughout repetitions. High professionalism is a necessity for reliable results that display consistency over time. And this will require the appropriate technical training, such as what might be expected from school nurses. In addition, it should not be impossible to locate athletic coaches with the appropriate expertise. These and other factors should not be glossed over. The time and money essential for such a program could represent considerable waste without adequate attention to these concerns. Without efficient execution and quality control based on informed professional expertise, it will be a waste of school resources. The potential for mistreatment and abuse of children by their peers qualifies as another drawback in widespread implementation of a body mass index evaluation system. But to be conducted on a large scale, public school would seem to be the most likely environment where such measures could be undertaken in a time and place where positive health outcomes are likely. Other drawbacks can include problems that occur in any task with significant repetition; The tedious nature of the task that can lead to carelessness. Taking the measurements of hundreds of students would qualify in this regard. To alleviate this concern, additional expertise should be sought in the form of quality control. Possibilities to improve the accuracy of the measurement process might include comparisons with previous measurements taken in the same year with an eye towards anomalous measurements that might seem incongruent with typical growth patterns of that age group. There are of course, additional methods of body fat analysis using calipers. This is potentially useful as a directing means to identify the individual’s fat content, but also not without certain difficulties. School-age children may become actively resistant at the thought of being pinched by a potentially painful instrument. Furthermore, not all individuals store fat in the same way, in the same places. Simple observation will confirm that fat distributions and storage differs between men and women. In order to give a complete measurement of body fat using calipers it would be necessary to evaluate fat storage for each individual. Often in school districts, where it is most relevant to identify dangerous trends in body fat, it is necessary to measure large numbers of students. The use of calipers could require an importunate amount of time, as compared with weight height calculations using the body mass index. In any event, a system that permits rapid screening with easily repeatable results is necessary with respect to large numbers of individuals. Repetition is important in the interest of accuracy. Attention must be given towards measurements that disagree with prior tests. Experts suggest that each measurement be taken twice, and arguably from different positions to ensure accuracy. To measurements must be in agreement within at least one fourth of a pound or one fourth of an inch for height. Otherwise, an additional pair of measurements must be taken until agreement is reached. (Gance-Cleveland & Bushmiaer, 2005) The possibility of a body mass index measurement program should be introduced gradually, with an eye towards the limitations and challenges described above. In the school setting, parents and guardians should be introduced to the concept with the description of the projected health benefits. These selfsame parents and guardians should be involved – to the extent that it is practical in the planning process. With respect to the wishes of parents, arguably the option should exist to opt out of the body mass index measurements altogether, at the parent’s discretion. For the sake of efficiency, the refusal should probably be written. Here there is the possibility for misunderstanding as well, due to the potential that some parents might simply neglect to follow up on medical recommendations even after their child is officially designated as obese. (Johnson & Ziolkowski, 2006) The potential also exists that the community may have insufficient resources to adequately assist in the creation of a weight loss program for the child. This creates an additional burden upon the school to provide lifestyle alternatives that will support the objectives behind these calculations. There are also a number of purely technical considerations. Care must be taken to ensure that students with elaborate hairstyles are not incorrectly estimated. Shoes and jackets or other heavy accoutrements must be removed whenever possible prior to the measurement. Misconceptions and anxiety are a possibility, and not only from the students, and thus a clear description of the program aims and objectives should be made publicly available. Such a program should be undertaken will strictly in the interest of student health, it should be made clear that there is no aesthetic agenda, whereby the appearance of any particular student is being judged. Yet in the interest of preventing bullying or mistreatment, the exact results of the body mass analysis for each student arguably should remain confidential. Concerns such as these lead to additional criticisms with respect to body mass index calculations. Low self-esteem and/or depression certainly is a possibility among those who are clearly obese, especially if there is clear documentation that establishes their condition. As described above, this can lead to a damaging self image for the individual, in addition to further challenges as a result of peer bullying. It is not difficult to extrapolate the possibility of anorexia in order to compensate. The possibility also exists among school-aged children that misunderstandings of the results of the body mass index might occur, leading to unjustified anxiety and irrational doubts concerning health and body image. This might theoretically lead to a negative spiral of irrational self criticism that could harm otherwise normal students without counseling and effective education. Harmful reactions of course, are not simply limited to the children. A misconstrued body mass index report might also prompt parents to put their children at risk with damaging behaviors, or unnecessarily harsh dietary regimens. With an official report originating from the school nurse, there is the possibility that additional medical expertise will not be sought, thereby putting the child at additional risk in the absence of sound medical advice. The potential exists that harmful dieting, with overly harsh strictures that do not take a comprehensive spectrum of nutritional needs into account could do more harm than good. Intuitively, it is understood that extreme dieting would be much more difficult to adhere to as a consistent lifestyle choice. Thus, weight fluctuations become a genuine concern, as well as the simple threat of malnutrition as a result of reactive dieting. Also in the case of children, parents and educators must take into account possible impediments to the normal growth process resulting from extreme changes in diet. More data is needed to fully assess the risk factors from Ms. understood reactions to a body mass index report. PRACTICAL APPLICATIONS Despite the setbacks above, such programs have the potential to alert and educate parents of potential health risks if overseen by responsible, well informed professionals. It might seem 'obvious' that certain children are obese, yet their parents may not always perceive it that way. Some parents may be accustomed to excess body weight and may have an incomplete understanding of the accompanying risk factors which a standardized program could educate them about. Any misconceptions concerning who exactly is obese, and who is not should be addressed by trained experts. More research is needed to determine the ultimate, long-term effectiveness of body mass index education programs as a means of preventing obesity. However, it does have considerable potential as a pre-screening method. It is relatively simple to acquire the measurements on large numbers of people, as would be required in a school setting. And identifying and rectifying excess body fat in the young is likely to have the most health benefits for the public at large. Assisting children in growing up with a healthy weight creates a better chance of producing healthy adults. The public school setting is also the time and place where government funding could be most efficiently utilized in order to combat obesity. With respect to the technique itself, whether body mass index is truly useful as a method of ascertaining body fat, it is necessary to clarify the ultimate objective: if the goal is to identify large segments of the population and rapidly screen individuals at risk for obesity and its resultant health problems, then measurements of body mass index appears to be the most efficient option presently available. If the objective is to identify unusual health problems in individual, then more precise methods should be employed. Clinical methods could be utilized to give more precise measurements at a greater expenditure of time and cost than would be available for a school district. With regards to formulating a specific weight loss regimen, a more logical conclusion is for a nutritionist or other medical professional to employ clinical tests, and calipers to give a more precise estimation of body fat content. It is simply a question of the objective. For large numbers of people, then the use of the body mass index calculations is an effective choice. REFERENCES American Medical Association 2007.Expert Committee releases recommendations to fight childhood and adolescent obesity [press release]. Chicago, Ill: June 8, 2007. Available at: www.ama-assn.org/ama/pub/category/17674.html. Accessed: 6/4/2012. Gance-Cleveland, B., Bushmiaer, M. 2005. Arkansas school nurses’ role in statewide assessment of body mass index to screen for overweight children and adolescents. J Sch Nurs. 2005;21 (2):64-69. Hedley, A.A., Ogden, C.L., Johnson, C.L., Carroll, M.D., Curtin, L.R., Flegal, K.M. 2004. Prevalence of overweight and obesity among U.S. children, adolescents, and adults, 1999-2002. JAMA. 2004; 291(23):2847-2850. Johnson. A., Ziolkowski, G.A. 2006. School-based body mass index screening program. Nutr Today. 2006;41(6):274-279. Kaminer, B., Lutz, W.P., 1960. Blood Pressure in bushmen of the Kalahari desert. Circulation 22:289-95 (1960). National Heart Foundation in association with the Faculty of Public Health, 2007. Department of Health, 2007. Lightening the load: tackling overweight and obesity: a toolkit for developing local strategies to tackle overweight and obesity in children and adults. [Online] London: Department of Health. Available at: http://www.dh.gov.uk/en/Publicationsandstatistics/Publications/PublicationsPolicyAndGuidance/DH_073936 [Accessed June 2012]. National Obesity Observatory, 2009. Body Mass Index as a measure of obesity. Association of Public Health Observatories. June, 2009. Nihiser, A. 2010. Body Mass Index Measurement in Schools. 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Available at: nces.ed.gov/programs/digest/d04/list_tables1.asp#c1_2. Accessed 6/4/2012. Whyte, H.M. 1958. Body fat and blood pressure of natives in New Guinea: Reflections on essential hypertension. Aust.Med. 7:36-46 (1958) Read More