Body Mass Index and Waist Circumference Considerations
New fields have been entered into CIS to enter student height, weight, and waist circumference. The body-mass index (BMI) is automatically calculated when height and weight are entered.
Why Are We Measuring Both BMI and Waist Circumference?
BMI is a widely used measurement of weight status. It can give a quick assessment of a person's risk of health-related diseases.
However, BMI does not differentiate between fat and muscle. Some people, especially men who lift weights, who are at a healthy body fat percentage may have a BMI that puts them in the overweight range. Other people may lose fat and build muscle. In this case, the person's BMI might not change, but he or she will have a healthier body composition.
Excess fat located in the abdominal area is also more dangerous than excess fat located in other areas of the body. People who carry weight around their waist are more likely to develop health problems than those who carry excess weight in their lower body. Women with a waist measurement of 35 inches or more and men with a waist measurement of 40 inches or more are at a higher risk of disease.1
The National Office will use these numbers to determine whether students are gaining, losing, or maintaining weight and whether their waist circumference changes while in Job Corps. Together, these measurements will give us the best possible picture of changes in students' health status while in Job Corps. Both measurements can be taken in less than two minutes.
When Should We Measure a Student's Height, Weight, and Waist Circumference?
You should make every attempt to take these measurements on every student, every time they visit the Health and Wellness Center. You should record these measurements in CIS.
What Are Appropriate BMI Categories?
BMI categories are as follows:
- Underweight: BMI less than 18.5
- Normal weight: 18.5-24.9
- Overweight: 25-29.9
- Obesity: BMI of 30 or greater
Is There a Good Online BMI Calculator Available?
Yes. CIS automatically calculates BMI, but if you want to view a calculator when you are away from center, the National Heart Lung and Blood Institute provides an easy-to-use calculator.
How Do I Measure Waist Circumference?
Place a tape measure around the student's bare abdomen just above their hip bone. The tape should be snug, but should not compress the skin. Have the student exhale and then take the measurement.
Is It True that BMI Is Not Valid for All Racial Groups?
Yes and no. BMI scales also might not tell the whole story when working with different racial and ethnic groups.2 Asian populations experience weight-related diseases such as type 2 diabetes at a lower BMI than European populations. Some experts have suggested that the overweight cut-off point for some Asian populations should be dropped as low as 22 kg/m2.3 New research suggests that BMI might overestimate obesity in African-Americans. A recent study compared BMI in African American and Caucasian men and women. When matched by age, gender, weight circumference, weight, and height, the African American subjects had less body fat. Data suggests that muscle mass may be higher in African Americans than Caucasians.4
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1 National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). (2008). Weight and Waist Measurement: Tools for Adults. NIH Publication No. 04–5283; Bethesda, MD.
2 Caroll, J.F., Chiapa, A.L., Rodriguez, M., Phelps, D.R., Cardarelli, K.M., Vishwanatha, J.K., Bea, S., & Cardarelli, R. (2008). Visceral fat, waist circumference, and BMI: impact of race/ethnicity. Obesity. 16(3):600-7.
3 World Health Organization. (2004). Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. The Lancet. 363;159-163.
4 The Endocrine Society (2009, June 22). Widely Used Body Fat Measurements Overestimate Fatness In African-Americans, Study Finds. ScienceDaily. Retrieved on June 17, 2010.