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Body fat measurement by bioelectrical impedance and air displacement plethysmography: a cross-validation study to design bioelectrical impedance equations in Mexican adults.
Nutr J. 2007 Aug 15; 6:18.NJ

Abstract

BACKGROUND

The study of body composition in specific populations by techniques such as bio-impedance analysis (BIA) requires validation based on standard reference methods. The aim of this study was to develop and cross-validate a predictive equation for bioelectrical impedance using air displacement plethysmography (ADP) as standard method to measure body composition in Mexican adult men and women.

METHODS

This study included 155 male and female subjects from northern Mexico, 20-50 years of age, from low, middle, and upper income levels. Body composition was measured by ADP. Body weight (BW, kg) and height (Ht, cm) were obtained by standard anthropometric techniques. Resistance, R (ohms) and reactance, Xc (ohms) were also measured. A random-split method was used to obtain two samples: one was used to derive the equation by the "all possible regressions" procedure and was cross-validated in the other sample to test predicted versus measured values of fat-free mass (FFM).

RESULTS AND DISCUSSION

The final model was: FFM (kg) = 0.7374 * (Ht2 /R) + 0.1763 * (BW) - 0.1773 * (Age) + 0.1198 * (Xc) - 2.4658. R2 was 0.97; the square root of the mean square error (SRMSE) was 1.99 kg, and the pure error (PE) was 2.96. There was no difference between FFM predicted by the new equation (48.57 +/- 10.9 kg) and that measured by ADP (48.43 +/- 11.3 kg). The new equation did not differ from the line of identity, had a high R2 and a low SRMSE, and showed no significant bias (0.87 +/- 2.84 kg).

CONCLUSION

The new bioelectrical impedance equation based on the two-compartment model (2C) was accurate, precise, and free of bias. This equation can be used to assess body composition and nutritional status in populations similar in anthropometric and physical characteristics to this sample.

Authors+Show Affiliations

Centro de Investigación en Nutrición y Salud, Instituto Nacional de Salud Pública. Universidad 655, Santa Maria Ahuacatitlan, CP 62508, Cuernavaca, México. nmacias@insp.mxNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Validation Study

Language

eng

PubMed ID

17697388

Citation

Macias, Nayeli, et al. "Body Fat Measurement By Bioelectrical Impedance and Air Displacement Plethysmography: a Cross-validation Study to Design Bioelectrical Impedance Equations in Mexican Adults." Nutrition Journal, vol. 6, 2007, p. 18.
Macias N, Alemán-Mateo H, Esparza-Romero J, et al. Body fat measurement by bioelectrical impedance and air displacement plethysmography: a cross-validation study to design bioelectrical impedance equations in Mexican adults. Nutr J. 2007;6:18.
Macias, N., Alemán-Mateo, H., Esparza-Romero, J., & Valencia, M. E. (2007). Body fat measurement by bioelectrical impedance and air displacement plethysmography: a cross-validation study to design bioelectrical impedance equations in Mexican adults. Nutrition Journal, 6, 18.
Macias N, et al. Body Fat Measurement By Bioelectrical Impedance and Air Displacement Plethysmography: a Cross-validation Study to Design Bioelectrical Impedance Equations in Mexican Adults. Nutr J. 2007 Aug 15;6:18. PubMed PMID: 17697388.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Body fat measurement by bioelectrical impedance and air displacement plethysmography: a cross-validation study to design bioelectrical impedance equations in Mexican adults. AU - Macias,Nayeli, AU - Alemán-Mateo,Heliodoro, AU - Esparza-Romero,Julián, AU - Valencia,Mauro E, Y1 - 2007/08/15/ PY - 2006/10/30/received PY - 2007/08/15/accepted PY - 2007/8/19/pubmed PY - 2007/12/6/medline PY - 2007/8/19/entrez SP - 18 EP - 18 JF - Nutrition journal JO - Nutr J VL - 6 N2 - BACKGROUND: The study of body composition in specific populations by techniques such as bio-impedance analysis (BIA) requires validation based on standard reference methods. The aim of this study was to develop and cross-validate a predictive equation for bioelectrical impedance using air displacement plethysmography (ADP) as standard method to measure body composition in Mexican adult men and women. METHODS: This study included 155 male and female subjects from northern Mexico, 20-50 years of age, from low, middle, and upper income levels. Body composition was measured by ADP. Body weight (BW, kg) and height (Ht, cm) were obtained by standard anthropometric techniques. Resistance, R (ohms) and reactance, Xc (ohms) were also measured. A random-split method was used to obtain two samples: one was used to derive the equation by the "all possible regressions" procedure and was cross-validated in the other sample to test predicted versus measured values of fat-free mass (FFM). RESULTS AND DISCUSSION: The final model was: FFM (kg) = 0.7374 * (Ht2 /R) + 0.1763 * (BW) - 0.1773 * (Age) + 0.1198 * (Xc) - 2.4658. R2 was 0.97; the square root of the mean square error (SRMSE) was 1.99 kg, and the pure error (PE) was 2.96. There was no difference between FFM predicted by the new equation (48.57 +/- 10.9 kg) and that measured by ADP (48.43 +/- 11.3 kg). The new equation did not differ from the line of identity, had a high R2 and a low SRMSE, and showed no significant bias (0.87 +/- 2.84 kg). CONCLUSION: The new bioelectrical impedance equation based on the two-compartment model (2C) was accurate, precise, and free of bias. This equation can be used to assess body composition and nutritional status in populations similar in anthropometric and physical characteristics to this sample. SN - 1475-2891 UR - https://www.unboundmedicine.com/medline/citation/17697388/Body_fat_measurement_by_bioelectrical_impedance_and_air_displacement_plethysmography:_a_cross_validation_study_to_design_bioelectrical_impedance_equations_in_Mexican_adults_ L2 - https://nutritionj.biomedcentral.com/articles/10.1186/1475-2891-6-18 DB - PRIME DP - Unbound Medicine ER -