Protocol - Waist Circumference - Waist Circumference NCFS
Waist circumference is measured at several body sites in the scientific literature. During the National Children’s Food Survey, the participant’s waist circumference was measured midway between the lowest rib and the iliac crest. This protocol is used most commonly for adults and children in European, Asian, and South American surveys and studies, and for children, several area- or country-specific references are available to define a 90th percentile cutoff, which is the main criterion for metabolic syndrome in children. This is important because there are ethnic-specific cutoffs for central (i.e., abdominal) obesity in adults using waist circumference, and it is presumed that comparable racial/ethnic differences exist for children and adolescents. In both children and adults, and compared with measurements taken using other protocols, measurements taken midway between the lowest rib and the iliac crest tend to be several centimeters smaller than measurements taken over the iliac crest (NHANES protocol). It is more comparable with measurements taken at the level of the umbilicus (Framingham protocol), except when waist circumference is measured at the level of the umbilicus in an obese participant, and the umbilicus has been displaced downward (i.e., pendulous abdomen). This measurement can be used to calculate a waist-to-height ratio (WHtR) because it will accurately estimate the prevalence in the abnormal range (WHtR greater than 0.5). The relationship of this measure with cardiometabolic risk factors is also comparable with waist circumference measures taken at other sites.
NOTE: Waist circumference can be measured on pregnant women. However, national reference data do not include pregnant women, and waist circumference has different associations with abdominal and total body fat among those who are not pregnant.
Several overarching, critical issues for high-quality data collection of anthropometric measures that optimize the data in gene-environment etiologic research include (1) the need for training (and retraining) of study staff in anthropometric data collection; (2) duplicate collection of measurements, especially under field conditions; (3) use of more than one person for proper collection of measurements where required; (4) accurate recording of the protocols and measurement units of data collection; and (5) use of required and properly calibrated equipment.
The notion of recommending replicate measurements comes from the reduction in random errors of measurement and accompanying improved measurement reliability when the mean of multiple measurements is used rather than a single measurement. This improvement in measurement reliability, however, depends on the reliability of a single measurement in the hands of the data collectors in a particular study (Himes, 1989). For example, if a measure such as recumbent length in a given study has a measurement reliability of 0.95 (expressed as an intraclass correlation coefficient), taking a second measurement and using the mean of the two measurements in analyses will improve the reliability to only 0.97, yielding only a 2% reduction in error variance for the additional effort. If, in the same study, the reliability of a single triceps skinfold measurement was 0.85, using the mean, including a replicate measurement, would raise the reliability to 0.92 and yield a 7% reduction in error variance, more than a three-fold improvement compared with recumbent length. The intraclass correlation coefficient is specifically recommended here for assessing reliability because it takes account of both random and systematic errors of measurement, whereas the interclass correlation (e.g., Pearson correlation) takes account of only random errors of measurement.
Because the benefits of taking replicate measurements are so closely linked with the existing measurement reliability, it is recommended that as a part of the training of those who will be collecting anthropometry data, a reliability study be conducted that will yield measurement reliability estimates for the data collectors, protocols, settings, and participants involved in that particular study (Himes, 1989). If the measurement reliability for a single measurement is greater than or equal to 0.95, the recommendation is that replicate measurements are not necessary and will yield little practical benefit. If the measurement reliability is less than 0.95, the recommendation is to include replicate measurements as prescribed.
If replicate measurements are indicated because of relatively low reliability, a second measurement should be taken, including repositioning the participant. A third measurement should be taken if the first two measurements differ by more than 1.0 cm in those 12 years or older and by more than 0.50 cm in those younger than 12 years. If it is necessary to take a third measurement, the two closest measurements are averaged. Should the third measurement fall equally between the first two measurements, all three should be averaged.
Waist measurement at midpoint between lowest rib and iliac crest:
Waist circumference was measured in duplicate using a non-stretch tape measure. First, the midpoint of the distance between the iliac crest (top of hip) and the bottom of the rib cage (10th rib) was identified and marked. Waist circumference was then measured at the midpoint. Measurement is taken to the nearest 0.1 cm.
- If you have problems palpating the rib, ask the participant to breathe in very deeply. Locate the rib and as participant breathes out, follow the rib as it moves down with your finger.
It is essential that the waist measurement is taken midway between the iliac crest and the lower rib and that the tape is horizontal. Therefore, adjust any clothing items to ensure that measurement is taken per above guidelines: that is, ensure that tape measure follows body lines, not clothing lines. Interpretation of Findings Waist circumference has become an important indicator of obesity and especially of abdominal obesity, including visceral and subcutaneous fat at the site measured. Often, it is compared with appropriate reference data for populations. The exact site, ages, and protocols used in the reference data need to be carefully identified; although several different body sites have been used, the actual measurement may differ considerably based on the site measured. Investigators should be sure to match the specific location of the waist circumference measurement with the reference data used.
Waist circumference is often a measurement criterion for defining metabolic syndrome. Because of the considerable changes in waist circumference with age and variation by gender, attention must be given to these factors when interpreting results.
Several references are provided as follows for discussions of appropriate applications of waist circumference measurements and applications related to waist-to-hip ratio and metabolic syndrome.
Personnel and Training Required
Trained examiner: Individuals need to be trained to identify the waist location on persons of varying body mass; training should include dexterity in wrapping the tape around participants, in ensuring a horizontal plane for measurement, in using one standardized tape measure, in positioning the tape measure; and in knowing how to measure adults and children. A pocket guide detailing the protocol is helpful for personnel to carry for review. Training should include methods for recording (e.g., forms, computer screens). Have all personnel practice on the same people to compare reproducibility of measurements and verify against an expert examiner to assure validity; retrain regularly on the same volunteer to ensure reproducibility.
Non-stretch tape measure
|Specialized requirements for biospecimen collection||No|
|Average time of greater than 15 minutes in an unaffected individual||No|
Mode of Administration
Participants aged 5-12 years, although the protocol can be used for those aged 2 years or older
The state of the science does not indicate a clear choice of protocol at this time. Therefore, the PhenX Expert Review Panel recommends that one protocol be selected in measuring the waist circumference and that the protocol correspond to the reference data used. Further, the exact protocol used should be recorded and reported.
These recommendations differ from those included in the original PhenX waist circumference protocols. Previously, slightly different protocols were recommended for youth and adults; these are now combined into three protocols appropriate for all age groups. Also, it is now recommended that only one protocol be used in a particular study rather than using all three protocols.
|caDSR Common Data Elements (CDE)||Person Waist Circumference Value||2793481||CDE Browser|
|Logical Observation Identifiers Names and Codes (LOINC)||Adult Waist Circumf||56086-2||LOINC|
|Human Phenotype Ontology||Abnormal waist to hip ratio||HP:0031818||HPO|
Waist-to-Hip Ratio (WHR), Waist-to-Height Ratio (WHtR)
Process and Review
The Expert Review Panel #1 reviewed the measures in the Anthropometrics, Diabetes, Physical Activity and Physical Fitness, and Nutrition and Dietary Supplements domains.
Guidance from the ERP includes:
Added replicate measure language
Changed unit of measurement
Back-compatible: no changes to Data Dictionary
Previous version in Toolkit archive (link)
Protocol Name from Source
2003 National Children’s Food Survey
Irish Universities Nutrition Alliance. (2003). Methodology used in the National Childrens Food Survey. Retrieved from http://www.iuna.net/docs/ncfs%20methodology.pdf
Because of the variability in the site of measurement of waist circumference, different cutoffs for metabolic syndrome in adults of various racial/ethnic groups, and variations among different populations of children and adolescents, more references are provided for potential users than for some other anthropometric measurements. Further, publications providing percentile curves (often including the 90th percentile) for children and adolescents have been included in the references as examples that may be suitable reference data for some investigations.
Alberti, K. G., Eckel, R. H., Grundy, S. M., Zimmet, P. Z., Cleeman, J. I., Donato, K. A., . . . Smith, S. C. (2009). Harmonizing the metabolic syndrome: A joint interim statement of the International Diabetes Federation Task Force on Epidemiology and Prevention; National Heart, Lung, and Blood Institute; American Heart Association; World Heart Federation; International Atherosclerosis Society; and International Association for the Study of Obesity. Circulation, 120(16), 1640-1645.
Brannsether, B., Roelants, M., Bjerknes, R., & Júlíusson, P. B. (2011). Waist circumference and waist-to-height ratio in Norwegian children 4-18 years of age: Reference values and cut-off levels. Acta Paediatrica, 100(12), 1576-82.
Bergen Growth Study, 2,945 boys and 2,780 girls, aged 4-18 years
Freedman, D. S., Serdula, M. K., Srinivasan, S. R., & Berenson, G. S. (1999). Relation of circumferences and skinfold thicknesses to lipid and insulin concentrations in children and adolescents: The Bogalusa Heart Study. American Journal of Clinical Nutrition, 69(2), 308-317.
Galcheva, S. V., Iotova, V. M., Yotov, Y. T., Grozdeva, K. P., Stratev, V. K., & Tzaneva, V. I. (2009). Waist circumference percentile curves for Bulgarian children and adolescents aged 6-18 years. International Journal of Pediatric Obesity, 4(4), 381-388.
Bulgarian children, 2,052 boys and 1,758 girls, aged 6-18 years
Harrington, D. M., Staiano, A. E., Broyles, S. T., Gupta, A. K., & Katzmarzyk, P. K. (2012). Waist circumference measurement site does not affect relationships with visceral adiposity and cardiometabolic risk factors in children. Pediatric Obesity, 8(3), 199-206.
Jackson, R. T., Al Hamad, N., Prakash, P., & Al Somaie. M. (2011). Waist circumference percentiles for Kuwaiti children and adolescents. Public Health Nutrition, 14(1), 70-76.
Kuwait Nutrition Surveillance System (KNSS), schoolchildren, 4,843 boys and 4,750 girls, aged 5-18.9 years
Ji, C. Y., Yt Sung, R., Ma, G. S., Ma, J., He, Z. H., & Chen, T. J. (2010). Waist circumference distribution of Chinese school-age children and adolescents. Biomedical and Environmental Sciences, 23(1), 12-20.
Hong Kong and 15 mainland China provinces, 160,225 children and adolescents, aged 7-18 years
Kuriyan, R., Thomas, T., Lokesh, D. P., Sheth, N. R., Mahendra, A., Joy, R., . . . Kurpad, A. V. (2011). Waist circumference and waist for height percentiles in urban South Indian children aged 3-16 years. Indian Pediatrics, 48(10), 765-771.
PEACH (Pediatric Epidemiology and Child Health) Study, Bangalore, urban preschool- and school-age children, 5,172 boys and 3,888 girls, aged 3-16 years
Mancini, M. C. (2009). Metabolic syndrome in children and adolescents: Criteria for diagnosis. Diabetology & Metabolic Syndrome, 1, 20 doi:10.1186/1758-5996-1-20
Mason, C., & Katzmarzyk, P. T. (2009). Variability in waist circumference measurements according to anatomic measurement site. Obesity, 17(9), 1789-1795. doi:10.1038/oby.2009.87
Ross, R., Berentzen, T., Bradshaw, A. J., Janssen, I., Kahn, H. S., Katzmarzyk, P. T., . . . Després, J. P. (2008). Does the relationship between waist circumference, morbidity and mortality depend on measurement protocol for waist circumference? Obesity Reviews, 9(4), 312-325.
Samson, S. L., & Garber, A. J. (2014). Metabolic syndrome. Endocrinology Metabolism Clinics of North America, 43, 1-23.
World Health Organization. (2011). Waist circumference and waist-hip ratio: Report of a WHO expert consultation, Geneva, 8-11 December 2008. World Health Organization: Geneva.
|Variable Name||Variable ID||Variable Description||dbGaP Mapping|
|PX021602010100||Measured circumference at the top of the more||N/A|
|PX021602010200||Measured circumference at the top of the more||N/A|
|PX021602010300||Measured circumference at the top of the more||N/A|
|PX021602010400||Measured circumference at the top of the more||N/A|
|PX021602020100||Waist circumference taken at the narrowest more||N/A|
|PX021602020200||Waist circumference taken at the narrowest more||N/A|
|PX021602020300||Waist circumference taken at the narrowest more||N/A|
|PX021602020400||Measured circumference at the top of the more||Variable Mapping|
|PX021602030100||Waist circumference taken at the narrowest more||N/A|
|PX021602030200||Waist circumference taken at the narrowest more||N/A|
|PX021602030300||Waist circumference taken at the narrowest more||N/A|
|PX021602030400||Measured circumference taken at the more||N/A|
March 27, 2009
Waist circumference is a measurement to estimate the abdominal circumference.
The measure of waist circumference is an indirect measure of abdominal fatness (central obesity), and a large waist circumference is associated with increased risk for diseases such as types 1 and 2 diabetes, dyslipidemia, hypertension, and cardiovascular disease. It is often used in conjunction with hip circumference to calculate the waist-to-hip ratio.
Anthropometrics, abdominal obesity, obesity, weight, girth, waist-to-hip ratio, WHR, waist-to-height ratio, WtHR, metabolic syndrome, NHANES, NCFS