Ethnic variation in body composition assessment in a sample of adolescent girls

Authors: Meyer, Katie A.; Friend, Sarah; Hannan, Peter J.; Himes, John H.; Demerath, Ellen W.; Neumark-Sztainer, Dianne

Source: International Journal of Pediatric Obesity, Volume 6, Numbers 5-6, October 2011 , pp. 481-490(10)

Publisher: Informa Healthcare

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Abstract:

<title>Abstract</title>

Objective. To compare body composition assessment by bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA) in a multiethnic sample of adolescent girls. Method. Data were from a physical activity intervention study among 254 14-20-year-old sedentary American girls, including 69 whites, 74 blacks, 42 Hispanics, and 69 Asians. Height and weight were objectively measured. Body composition was assessed using a foot-to-foot BIA and a fan-beam DXA. We calculated ethnic-specific estimates of percentage body fat (BF%), fat mass (FM), fat mass index (FMI), fat-free mass (FFM), and fat-free mass index (FFMI) from BIA and DXA. We used Bland-Altman plots to examine ethnic-specific agreement between BIA and DXA, and used linear regression to test whether the BIA-DXA difference varied across the mean. Results. Compared to DXA, BIA estimates of fat measures (BF%, FM, and FMI) were lower and lean tissue measures (FFM and FFMI) higher. For example, the BIA-estimated BF% was lower than the DXA estimate by between 4.9% (95% CI: −5.9, −3.9) in blacks and 8.7% (−7.0, −5.0) in Asians, with large limits of agreement (−15.4 to −5.4 in blacks and −16.8 to −0.4 in Asians). Regression analysis showed that BIA-DXA differences were not constant across means for any body composition measure among Asians or for any measure except BF% among whites. Conclusion. Compared to DXA, BIA yielded lower estimates of adiposity in a multiethnic adolescent sample. BIA-DXA differences varied by ethnicity, and across mean body composition values for some ethnicities.

Keywords: Bioelectrical impedance; dual-energy X-ray absorptiometry; ethnicity; race; adiposity; body composition; female; adolescent

Document Type: Research article

DOI: http://dx.doi.org/10.3109/17477166.2011.596841

Affiliations: 1: Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, MN, USA

Publication date: 2011-10-01

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