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Evaluating body fat in girls and female adolescents: advantages and disadvantages of dual-energy X-ray absorptiometry

来源：《美国临床营养学杂志》
摘要：ABSTRACTBackground:Withinthepast10y,dual-energyX-rayabsorptiometry(DXA)hasbecomeoneofthemostwidelyusedmethodsofmeasuringhumanbodycomposition。However,DXAhasnotbeenfullyevaluatedagainstanindependentcriterionmethodofmeasuringbodyfatnessinyoungfemales。Obje......

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William W Wong, Albert C Hergenroeder, Janice E Stuff, Nancy F Butte, E O’Brian Smith and Kenneth J Ellis

1 From the US Department of Agriculture/Agricultural Research Service Children’s Nutrition Research Center and Texas Children’s Hospital, Department of Pediatrics, Baylor College of Medicine, Houston.

2 The contents of this article do not necessarily reflect the views or policies of the USDA, and mention of trade names, commercial products, or organizations does not imply endorsement by the US Government.

3 Supported in part by the USDA/ARS under Cooperative Agreement no. 58-6250-6-001.

4 Address reprint requests to WW Wong, USDA/ARS Children’s Nutrition Research Center, 1100 Bates Street, Houston, TX 77030. E-mail: wwong{at}bcm.tmc.edu.


ABSTRACT  
Background: Within the past 10 y, dual-energy X-ray absorptiometry (DXA) has become one of the most widely used methods of measuring human body composition. However, DXA has not been fully evaluated against an independent criterion method of measuring body fatness in young females.

Objective: Our objective was to determine the bias and agreement between DXA and a 4-compartment model in predicting the percentage of fat mass (%FM) in a multiethnic group of young females.

Design: The %FM values measured by DXA of 73 white, 43 African American, 14 Hispanic, and 11 Asian females with a mean (± SD) age of 13.0 ± 1.9 y were compared with the 4-compartment values, which were based on measurements of body density, body water, and bone mineral content.

Results: The %FM values measured by the 2 methods were correlated at r = 0.90 with an SEE of 3.3%; Bland-Altman analysis indicated an average bias of 3.9%. After nullification of the average bias, an individual estimate of %FM by DXA could be underestimated or overestimated by 6.7% when compared with the 4-compartment value.

Conclusions: DXA is an appropriate method for estimating body composition in a group of young females because its bias and limits of agreement are independent of age, ethnicity, and body fatness. However, the limits of agreement of 6.7% could cause an individual FM value to be underestimated or overestimated by 28% relative to the 4-compartment value. Therefore, DXA may not be the optimal method of measuring the body fatness of young females.

Key Words: Body fat • percentage of fat mass • fat-free mass • girls • female adolescents • densitometry • isotope dilution • dual-energy X-ray absorptiometry • 4-compartment model


INTRODUCTION  
Since the development of dual-energy X-ray absorptiometry (DXA) in the early 1990s (1), DXA has emerged as one of the most widely accepted methods of measuring body composition in human subjects. The popularity of DXA can be attributed partly to its speed, ease of performance, and low radiation exposure (2). However, DXA has not been evaluated in comparison with a criterion method of measuring body fat in young females, despite a pattern of disturbing increases in excessive weight, particularly among African Americans and Hispanics (3).

Recently, on the basis of data collected on children and adolescents in the 1999 National Health and Nutrition Examination Survey (NHANES), officials from the National Center for Health Statistics (NCHS) voiced concern that the increase in obesity among America’s youth that had begun in the 1980s appears to be continuing (4). Because body weight in adulthood is strongly associated with body weight in adolescence (5), the NCHS interpreted the most recent NHANES data as suggesting the likelihood of another generation of adults who may be at risk for overweight and obesity-related health conditions. Because body weight and body mass index are poor indicators for assessing the true degree of adiposity (6), it is essential to determine the percentage of body fat with the most accurate methodology.

The aim of this study was to evaluate the level of agreement between DXA and the 4-compartment criterion model in estimating body fat in a multiethnic group of young females.

SUBJECTS AND METHODS
Human subjects
A total of 141 young females (73 whites, 43 African Americans, 14 Hispanics, and 11 Asians) participated in the study. The young females, who were between 9 and 17 y of age, were recruited from schools in the greater Houston metropolitan area. All subjects were healthy and nondiabetic at the time of the study. The Institutional Review Board for Human Research at Baylor College of Medicine approved the protocol. All subjects and their parents gave written, informed consent. The study was part of a larger study to define the body composition and energy metabolism of pregnant teenagers. None of the young females in the present study were pregnant.

Sexual maturity evaluation
Sexual maturity was determined from a physical examination by a physician according to the Tanner stages of classification (7).

Anthropometric measurements
On admission to the Children’s Nutrition Research Center, each subject’s body weight was measured to the nearest 0.1 kg with an electronic scale (Scale-Tronix, Wheaton, IL), and height was measured to the nearest 0.1 cm with a stadiometer (Holtain Ltd, Croswell, Crymych, United Kingdom). One investigator (JES) made all the anthropometric measurements.

Dual-energy X-ray absorptiometry
Fat mass (FM), fat-free mass (FFM), and bone mineral content (BMC) were measured by DXA (Hologic QDR-2000W, software version 5.56; Hologic, Inc, Waltham, MA) with the pencil beam. The Hologic instrument uses a single scan mode for all subjects aged  8 y. The fundamental principles and operating procedures of DXA have been extensively described in the literature (1, 8–13) and will not be presented here.

Four-compartment criterion method
The reference values for percentage of fat mass (%FM) were obtained by using a 4-compartment model as follows (14)

ACKNOWLEDGMENTS  
We are indebted to the volunteers; to the staff of the Metabolic Research Unit of the Children’s Nutrition Research Center for meeting the needs of the subjects during the study; to J Hoyle in the Pediatric Department of Kelsey-Seybold West Clinic; to M desVignes-Kendrick, Director of the City of Houston Health and Human Services Department; to X Earlie, Director of Sciences of the Aldine Independent School District; to S Wooten, Principal of the Teague Middle School; to B Shargey, Dean of Instruction, and CC Collins, Principal, of the High School for Health Professions; to K Wallace for subject recruitment; to M Puyau and FA Vohra for the underwater weighing measurements; to R Shypailo and J Pratt for the dual-energy X-ray absorptiometry measurements; to L Clarke, S Zhang, and K Usuki for the isotope ratio mass spectrometric measurements; and to Children’s Nutrition Research Center Editor L Loddeke.


REFERENCES  

  1. Pietrobelli A, Formica C, Wang Z, Heymsfield SB. Dual-energy x-ray absorptiometry body composition model: review of physical concepts. Am J Physiol 1996;271:E941–51.
  2. Njeh CF, Fuerst T, Hans D, Blake GM, Genant HK. Radiation exposure in bone mineral density assessment. Appl Radiat Isot 1999;50:215–36.
  3. Troiano RP, Flegal KM, Kuczmarski RJ, Campbell SM, Johnson CL. Overweight prevalence and trends for children and adolescents. Arch Pediatr Adolesc Med 1995;149:1085–91.
  4. National Center for Health Statistics. Prevalence of overweight among children and adolescents: United States, 1999. April 2002. Internet: http://www.cdc.gov/nchs/products/pubs/pubd/hestats/overwght99.htm (accessed 5 June 2002).
  5. Casey VA, Dwyer JT, Coleman KA, Valadian I. Body mass index from childhood to middle age: a 50-y follow up. Am J Clin Nutr 1992;56:14–8.
  6. Glantz SA. The special case of two groups: the t test. In: Laufer RS, Geno TK, eds. Primer of biostatistics. New York: McGraw-Hill, 1981:63–93.
  7. Tanner JM, Whitehouse RH. Variations of growth and development at puberty. Atlas of children’s growth, normal variation and growth disorders. New York: Academic Press, 1982:122–7.
  8. Snead DB, Birge SJ, Kohrt WM. Age-related differences in body composition by hydrodensitometry and dual-energy x-ray absorptiometry. J Appl Physiol 2000;74:770–5.
  9. Wang J, Heymsfield SB, Aulet M, Thornton JC, Pierson RN Jr. Body fat from body density: underwater weighing vs. dual-photon absorptiometry. Am J Physiol 1989;256:E829–34.
  10. Mazess RB, Peppler WW, Gibbons M. Total body composition by dual-photon (153Gd) absorptiometry. Am J Clin Nutr 1984;40:834–9.
  11. Pritchard JE, Nowson CA, Strauss BJ, Carlson JS, Kaymakci B, Wark JD. Evaluation of dual energy X-ray absorptiometry as a method of measurement of body fat. Eur J Clin Nutr 1993;47:216–28.
  12. Roubenoff R, Kehayias JJ, Dawson-Hughes B, Heymsfield SB. Use of dual-energy x-ray absorptiometry in body-composition studies: not yet a "gold standard." Am J Clin Nutr 2000;58:589–91.
  13. Ellis KJ, Abrams SA, Wong WW. Body composition of a young, multiethnic female population. Am J Clin Nutr 1997;65:724–31.
  14. Boileau RA, Lohman TG, Slaughter MH. Exercise and body composition of children and youth. Scand J Sports Sci 1985;7:17–27.
  15. Siri WE. Body composition from fluid spaces and density: analysis of methods. In: Brozek J, Hanschel A, eds. Techniques for measuring body composition. Washington, DC: National Academy of Science, 1961:223–44.
  16. Akers R, Buskirk ER. An underwater weighing system utilizing "force cube" transducers. J Appl Physiol 1969;26:649–52.
  17. Wilmore JH. A simplified method for determination of residual lung volumes. J Appl Physiol 1969;27:96–100.
  18. Wong WW, Lee LS, Klein PD. Deuterium and oxygen-18 measurements on microliter samples of urine, plasma, saliva, and human milk. Am J Clin Nutr 1987;45:905–13.
  19. Speakman JR, Nair KS, Goran MI. Revised equations for calculating CO2 production from doubly labeled water in humans. Am J Physiol 1993;264:E912–7.
  20. Wong WW, Klein PD. A review of techniques for the preparation of biological samples for mass-spectrometric measurements of hydrogen-2/hydrogen-1 and oxygen-18/oxygen-16 isotope ratios. Mass Spectrom Rev 1986;5:313–42.
  21. Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986;307–10.
  22. Lohman TG. Advances in body composition assessment. Champaign, IL: Human Kinetics, 1992:1–5.p
  23. Wong WW, Stuff JE, Butte NF, Smith EO, Ellis KJ. Estimating body fat in African American and white adolescent girls: a comparison of skinfold-thickness equations with a 4-compartment criterion model. Am J Clin Nutr 2000;72:348–54.
  24. Wong WW, Stuff JE, Butte NF, Smith EO, Ellis KJ. Estimation of body fat in Caucasian and African-American girls: total-body electrical conductivity methodology versus a four-compartment model. Int J Obes Relat Metab Disord 2000;24:1200–6.
  25. Mazess RB, Barden HS, Bisek JP, Hanson J. Dual-energy x-ray absorptiometry for total-body and regional bone-mineral and soft-tissue composition. Am J Clin Nutr 1990;51:1106–12.
  26. Goran MI, Driscoll P, Johnson R, Nagy TR, Hunter G. Cross-calibration of body-composition techniques against dual-energy X-ray absorptiometry in young children. Am J Clin Nutr 1996;63:299–305.
  27. Heymsfield SB, Wang J, Heshka S, Kehayias JJ, Pierson RN Jr. Dual-photon absorptiometry: comparison of bone mineral and soft tissue mass measurements in vivo with established methods. Am J Clin Nutr 1989;49:1283–9.
  28. Svendsen OL, Haarbo J, Hassager C, Christiansen C. Accuracy of measurements of body composition by dual-energy x-ray absorptiometry in vivo. Am J Clin Nutr 1993;57:605–8.
  29. Ellis KJ, Shypailo RJ, Schoknecht P, Pond WG. Neutron activation analysis: criterion method for evaluation of dual-energy x-ray absorptiometry measurements in infants. J Radioanal Nucl Chem 1995;195:139–44.
  30. Brunton JA, Bayley HS, Atkinson SA. Validation and application of dual-energy x-ray absorptiometry to measure bone mass and body composition in small infants. Am J Clin Nutr 1993;58:839–45.
  31. Laskey MA, Lyttle KD, Flaxman ME, Barber RW. The influence of tissue depth and composition on the performance of the Lunar dual-energy X-ray absorptiometer whole-body scanning mode. Eur J Clin Nutr 1992;46:39–45.
  32. Goodsitt MM. Evaluation of a new set of calibration standards for the measurement of fat content via DPA and DXA. Med Phys 1992;19:35–44.
  33. Modlesky CM, Lewis RD, Yetman KA, et al. Comparison of body composition and bone mineral measurements from two DXA instruments in young men. Am J Clin Nutr 1996;64:669–76.
  34. Pintauro SJ, Nagy TR, Duthie CM, Goran MI. Cross-calibration of fat and lean measurements by dual-energy X-ray absorptiometry to pig carcass analysis in the pediatric body weight range. Am J Clin Nutr 1996;63:293–8.
  35. Ellis KJ, Shypailo RJ, Pratt JA, Pond WG. Accuracy of dual-energy x-ray absorptiometry for body-composition measurements in children. Am J Clin Nutr 1994;60:660–5.
  36. Nord RH, Payne RK. Body composition by dual-enery X-ray absorptiometry—a review of the technology. Asia Pac J Clin Nutr 1995;4:167–71.
  37. Clark RR, Kuta JM, Sullivan JC. Prediction of percent body fat in adult males using dual energy x-ray absorptiometry, skinfolds, and hydrostatic weighing. Med Sci Sports Exerc 1993;25:528–35.
  38. Lohman TG. Assessment of body composition in children. Pediatr Exerc Sci 1989;1:19–30.
  39. Pietrobelli A, Wang Z, Formica C, Heymsfield SB. Dual-energy X-ray absorptiometry: fat estimation errors due to variation in soft tissue hydration. Am J Physiol 1998;274:E808–16.
  40. Park MK, Menard SW, Schoolfield J. Prevalence of overweight in a triethnic pediatric population in San Antonio, Texas. Int J Obes Relat Metab Disord 2001;25:409–16.
  41. Lohman TG. Applicability of body composition techniques and constants for children and youths. In: Pandolf KE, ed. Exercise and sports sciences reviews. New York: Macmillan, 1986:325–57.
  42. Lohman TG, Boileau RA, Slaughter MH. Body composition in children and youth. In: Boileau RA, ed. Advances in pediatric sport sciences. Champaign, IL: Human Kinetics, 1984:29–57.
  43. Yanovski JA, Yanovski SZ, Filmer KM, et al. Differences in body composition of black and white girls. Am J Clin Nutr 1996;64:833–9.
  44. Morrison JA, Barton BA, Obarzanek E, Crawford PB, Guo SS, Schreiber GB. Racial differences in the sums of skinfolds and percentage of body fat estimated from impedance in black and white girls, 9 to 19 years of age: The National Heart, Lung, and Blood Institute Growth and Health Study. Obes Res 2001;9:297–305.
  45. Goran MI, Nagy TR, Treuth MS, et al. Visceral fat in white and African American prepubertal children. Am J Clin Nutr 1997;65:1703–8.
  46. Wang J, Thornton JC, Russell M, Burastero S, Heymsfield S, Pierson RN Jr. Asians have lower body mass index (BMI) but higher percent body fat than do whites: comparisons of anthropometric measurements. Am J Clin Nutr 1994;60:23–8.
Received for publication March 30, 2001. Accepted for publication September 27, 2001.


作者： William W Wong
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