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F19L FREE COMMUNICATION/POSTER BODY COMPOSITION ASSESSMENT

COMPARISON OF BODY COMPOSITION ASSESSMENT METHODS IN INFANTS

Little, K D.1; Schubeck, D1

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Medicine & Science in Sports & Exercise: May 2001 - Volume 33 - Issue 5 - p S244
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Total body electrical conductivity (TOBEC) is considered the criterion method of body composition assessment in infants. Other methods for this population include dual energy x-ray absorptiometry (DEXA) and anthropometric equations, including one validated at our institution (Catalano et al. Am. J. Obstet. Gynecol. 173:1176–1181, 1995). The purpose of this study was to compare body composition by DEXA (D) and anthropometry (A) to TOBEC (T). 15 healthy, term infants (10 females; 5 males) were enrolled in the study with the following characteristics (mean ± sd): Age (wks) = 4.5 ± 1.9; Length (cm) = 54.3 ± 3.7; Weight (kg) = 4.241 ± 0.794. Body composition was assessed by T (EM-SCAN HP-2), D (Hologic QDR 2000, N = 10: 7 females; 3 males), and A (equation by Catalano et al.) on the same day. Results for %fat (%F) were (mean ± sd): T = 15.1 ± 4.9; D = 22.4 ± 6.5; A = 14.9 ± 2.8. Both D and A significantly (p < .002) correlated with T (D vs T, r = .869; A vs T, r = .787). While %F for A was similar to T (p = .875), D significantly differed from T (p = .0001). All 10%F values obtained by D overestimated that obtained by T (mean = +7.1%; range = +1.8 to +13.8%). Results for fat-free mass (FFM, kg) were (mean ± sd): T = 3.549 ± 682; D = 3.408 ± 660; A = 3.594 ± .593. Both D and A significantly (p = .0001) correlated with T (D vs T, r = .978; A vs T, r = .971). While FFM for A was similar to T (p = .778), D significantly differed from T (p = .013). 8 of 10 FFM values obtained by D underestimated that obtained by T (mean = −.141 kg; range = −.454 to +.045 kg). The results suggest that compared to T, A gives similar results while D significantly overstimates %F and significantly understimates FFM. Based on the results, we conclude that D is not an acceptable method for body composition assessment in infants. Support: General Clinical Research Center Grant (NIH:MO1RR00080)

©2001The American College of Sports Medicine