Weight and height measurements often constitute the basis of many calculations and tests. BMI, Body Mass Index, is a diagnostic tool that uses the person’s measurements to assess the level of body fatness. According to Ball, Dains, Flynn, Solomon, and Stewart (2015), BMI is the most widely used method used in healthcare to evaluate the patients’ total body fat and analyze their nutritional status. Therefore, one may assume that the reliability of this test is high. However, many scholars suggest that BMI cannot be viewed as infallible in assessing people’s nutrition and weight. Specific concerns for this test include its failure to account for various ethnic, cultural, social, and age-related characteristics of people.
It is crucial to identify how BMI is calculated and for which information it can be utilized in healthcare. In most situations, one uses the person’s weight in kilograms and divides it by “the square of height in meters” (Centers for Disease Control and Prevention [CDC], 2015, para. 2).
The CDC also offers measurements in inches and pounds for height and weight respectively. This calculation is simple, allowing clinicians to collect a minimal amount of information about the patient. The resulting number of the calculation is then attributed to a category, including underweight, normal weight, overweight, and obese (CDC, 2015). For example, a person with a BMI of 23 is considered to have a normal weight to height ratio. Here, the concerns arise whether a person should be declared unhealthy if their BMI does not put them in the “normal weight” category.
The primary concern about BMI’s reliability is mentioned on the CDC website – BMI cannot be used as the only diagnostic measure for people’s health and fitness levels. Nevertheless, many physicians include this calculation in the patients’ evaluation (Ball et al., 2015). BMI may be used by the health provider to assess the patients’ risk of diabetes, hypertension, increased cholesterol, arthritis, and other conditions. Nevertheless, it is not a reliable indicator of a person being healthy. For example, a smoker with a normal-range BMI is not healthy due to the low level of fat – this person is likely to be at risk of other problems. Similarly, people with a high or low BMI number may not have an increased risk for the mentioned above disorders.
There exist specific groups of people for which BMI should be considered with increased attention. Marković-Jovanović, Stolić, and Jovanović (2015) find that BMI is an untrustworthy factor in diagnosing pediatric obesity. The authors note that BMI has a low sensitivity and, thus, cannot be a sole indicator of obesity in children. They find that the level of non-concomitance among such tests as BMI, skinfold thickness, and waist circumference can reach 10% (Marković-Jovanović et al., 2015, p. 515).
Furthermore, BMI is also untrustworthy for older patients – Batsis et al. (2016) determine that adiposity cannot be measured with BMI in elderly patients, because their body fat and muscle mass become redistributed due to comorbidities and general aging processes. Moreover, Richmond et al. (2015) offer another point of concern – racial differences may render BMI even less reliable, especially if the data is self-reported. Finally, Nuttall (2015) points out that the main issue with BMI is that it does not perceive a difference between body fat and lean mass. Therefore, whole populations cannot rely on BMI for determining their height/weight ratio.
BMI is a popular tool that is easy to use because of the simple information that it requires. It is currently utilized to predict many problems and risks related to nutrition and weight. However, its low level of sensitivity lowers the test’s trustworthiness. Scholars argue that BMI cannot be used as a slow indicator of problems for younger and older patients. Furthermore, it may be unreliable due to ethnic differences of people and each person’s unique distribution of fat.
References
Ball, J. W., Dains, J. E., Flynn, J. A., Solomon, B. S., & Stewart, R. W. (2015). Seidel’s guide to physical examination (8th ed.). St. Louis, MO: Elsevier Mosby.
Batsis, J. A., Mackenzie, T. A., Bartels, S. J., Sahakyan, K. R., Somers, V. K., & Lopez-Jimenez, F. (2016). Diagnostic accuracy of body mass index to identify obesity in older adults: NHANES 1999–2004. International Journal of Obesity, 40(5), 761-767.
Centers for Disease Control and Prevention. (2015). Assessing your weight. Web.
Marković-Jovanović, S. R., Stolić, R. V., & Jovanović, A. N. (2015). The reliability of body mass index in the diagnosis of obesity and metabolic risk in children. Journal of Pediatric Endocrinology and Metabolism, 28(5-6), 515-523.
Nuttall, F. Q. (2015). Body mass index: Obesity, BMI, and health: A critical review. Nutrition Today, 50(3), 117-128.
Richmond, T. K., Thurston, I., Sonneville, K., Milliren, C. E., Walls, C. E., & Austin, S. B. (2015). Racial/ethnic differences in accuracy of body mass index reporting in a diverse cohort of young adults. International Journal of Obesity, 39(3), 546-548.