Equations based on anthropometry to predict body fat measured by absorptiometry in schoolchildren and adolescents☆

Ortiz-Hernández, Luis; López, A. Valeria Vega; Ramos-Ibáñez, Norma; Lara, L. Joana Cázares; Gómez, R. Joab Medina; Pérez-Salgado, Diana

doi:10.1016/j.jped.2016.08.008

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Original articles • J. Pediatr. (Rio J.) 93 (4) • Jul-Aug 2017 • https://doi.org/10.1016/j.jped.2016.08.008 copy

Equations based on anthropometry to predict body fat measured by absorptiometry in schoolchildren and adolescents^☆ ☆ Please cite this article as: Ortiz-Hernández L, Vega López AV, Ramos-Ibáñez N, Cázares Lara LJ, Medina Gómez RJ, Pérez-Salgado D. Equations based on anthropometry to predict body fat measured by absorptiometry in schoolchildren and adolescents. J Pediatr (Rio J). 2017;93:365-73.

Authorship SCIMAGO INSTITUTIONS RANKINGS

Abstract

Objective:

To develop and validate equations to estimate the percentage of body fat of children and adolescents from Mexico using anthropometric measurements.

Methods:

A cross-sectional study was carried out with 601 children and adolescents from Mexico aged 5-19 years. The participants were randomly divided into the following two groups: the development sample (n = 398) and the validation sample (n = 203). The validity of previously published equations (e.g., Slaughter) was also assessed. The percentage of body fat was estimated by dual-energy X-ray absorptiometry. The anthropometric measurements included height, sitting height, weight, waist and arm circumferences, skinfolds (triceps, biceps, subscapular, supra-iliac, and calf), and elbow and bitrochanteric breadth. Linear regression models were estimated with the percentage of body fat as the dependent variable and the anthropometric measurements as the independent variables.

Results:

Equations were created based on combinations of six to nine anthropometric variables and had coefficients of determination (r²) equal to or higher than 92.4% for boys and 85.8% for girls. In the validation sample, the developed equations had high r² values (≥85.6% in boys and ≥78.1% in girls) in all age groups, low standard errors (SE ≤ 3.05% in boys and ≤3.52% in girls), and the intercepts were not different from the origin (p > 0.050). Using the previously published equations, the coefficients of determination were lower, and/or the intercepts were different from the origin.

Conclusions:

The equations developed in this study can be used to assess the percentage of body fat of Mexican schoolchildren and adolescents, as they demonstrate greater validity and lower error compared with previously published equations.

KEYWORDS
Body fat; Children; Adolescents; Mexico; Dual X-ray absorptiometry; Anthropometry

	Development sample		Validation sample
	Boys (n = 191)	Girls (n = 207)	Boys (n = 100)	Girls (n = 103)
	% (n)	% (n)	% (n)	% (n)
Sexual maturity
Prepubescent	66.0 (126)	30.9 (64)	75.0 (75)	42.7 (44)
Pubescent	27.2 (52)	38.6 (80)	22.0 (22)	34.0 (35)
Post-pubescent	6.8 (13)	30.4 (63)	3.0 (3)	23.3 (24)
	Mean ± SD	Mean ± SD	Mean ± SD	Mean ± SD
Body fat (%)	27.1 ± 9.4	32.6 ± 7.0	25.8 ± 9.0	32.8 ± 7.4
Age (years)	11.3 ± 2.7	11.5 ± 2.9	10.9 ± 2.6	10.9 ± 2.9
Age ² (years ² )	136.0 ± 59.2^a a p ≤ 0.050.	141.1 ± 67.5^a a p ≤ 0.050.	133.3 ± 56.0	127.9 ± 62.6
Height (cm)	149.2 ± 16.9	146.2 ± 13.1^c c p ≤ 0.001.	144.2 ± 15.3	145.2 ± 13.7
Sitting height (cm)	76.9 ± 8.1	76.5 ± 7.2^b b p ≤ 0.010.	74.3 ± 7.5	75.5 ± 7.9
Sitting height ratio (%)	51.7 ± 1.8^a a p ≤ 0.050.	52.3 ± 1.9	51.6 ± 2.6	52.0 ± 2.7^a a p ≤ 0.050.
Weight (kg)	47.4 ± 15.9	45.0 ± 14.2	42.0 ± 14.3	43.7 ± 14.0
Body mass index (kg/m ² )	20.7 ± 4.2	20.5 ± 4.1	19.7 ± 3.8	20.3 ± 4.3
Arm circumference (cm)	24.2 ± 4.1	23.9 ± 3.8	23.2 ± 3.8	23.9 ± 3.7
Waist circumference (cm)	73.8 ± 12.9	72.0 ± 11.2	70.1 ± 11.4	72.5 ± 10.8
Triceps skinfold (mm)	14.9 ± 6.6^a a p ≤ 0.050.	16.7 ± 5.5	14.2 ± 6.3	17.2 ± 5.8
Biceps skinfold (mm)	8.3 ± 4.5^c c p ≤ 0.001.	9.0 ± 3.9^a a p ≤ 0.050.	7.7 ± 3.8^a a p ≤ 0.050.	9.8 ± 4.8^a a p ≤ 0.050.
Subscapular skinfold (mm)	14.2 ± 7.8^a a p ≤ 0.050.	15.7 ± 7.2	13.0 ± 7.6^b b p ≤ 0.010.	16.0 ± 9.2
Suprailiac skinfold (mm)	18.9 ± 12.7^a a p ≤ 0.050.	22.0 ± 12.0	16.0 ± 11.3^a a p ≤ 0.050.	21.9 ± 11.9
Calf skinfold (mm)	14.1 ± 6.7^a a p ≤ 0.050.	15.8 ± 6.5	12.4 ± 5.9^a a p ≤ 0.050.	16.0 ± 6.6
Bitrochanteric breadth (cm)	29.7 ± 4.9	29.5 ± 4.2	27.9 ± 4.4	29.3 ± 4.5
Elbow breadth (cm)	5.6 ± 0.6	5.1 ± 0.4	5.4 ± 0.6	5.1 ± 0.4

Equations	Multiple linear regression models	r² (%)	SE (%)
For boys
1	-8.739 - 0.384^c c p < 0.001. (height, cm) + 35.371^a a p < 0.050. (log weight, kg) - 0.892^b b p < 0.010. (BMI, kg/m²) - 0.299^a a p < 0.050. (arm circumference, cm) + 0.258^c c p < 0.001. (waist circumference, cm) + 17.732^c c p < 0.001. (log triceps skinfold) + 6.698^b b p < 0.010. (log subscapular skinfold) + 3.545^d d p ≤ 0.072. (log suprailiac skinfold) + 4.019^d d p ≤ 0.072. (log calf skinfold)	93.4	2.5
2	1.511 - 0.152^c c p < 0.001. (height, cm) - 0.431^c c p < 0.001. (arm circumference, cm) + 0.213^c c p < 0.001. (waist circumference, cm) + 21.271^c c p < 0.001. (log triceps skinfold) + 7.386^b b p < 0.010. (log subscapular skinfold) + 4.981^b b p < 0.010. (log suprailiac skinfold)	92.7	2.56
3	-1.791 + 0.329 (age, years) - 0.033^a a p < 0.050. (age², years²) - 0.141^c c p < 0.001. (height, cm) + 0.162^c c p < 0.001. (waist circumference, cm) + 18.516^c c p < 0.001. (log triceps skinfold) + 6.013^a a p < 0.050. (log subscapular skinfold) + 5.633^b b p < 0.010. (log suprailiac skinfold)	92.4	2.61

For girls
1	-7.299 - 21.436^b b p < 0.010. (log sitting height) + 17.739^b b p < 0.010. (log BMI) + 20.143^a a p < 0.050. (log waist circumference) + 7.813^c c p < 0.001. (log triceps skinfold) + 6.379^b b p < 0.010. (log subscapular skinfold) + 6.051^b b p < 0.010. (log calf skinfold) - 16.364^a a p < 0.050. (log elbow breadth)	85.8	2.65

	Boys							Girls
	Min	Max	Mean	r² (%)	SE (%)	α	p	Min	Max	Mean	r² (%)	SE (%)	α	p
8-18 years	n = 85							n = 84
%BF DXA	11.3	47.2	25.1					17.2	52.5	32.9
Equation 1	11.6	44.0	25.6	91.6	2.59	-0.64	0.478	17.2	45.3	33.0	78.1	3.52	0.39	0.841
Equation 2	12.2	44.6	25.7	90.7	2.72	-0.49	0.603
Equation 3	10.6	43.3	25.2	91.5	2.60	0.25	0.776
Slaughter^a a T-SF and C-SF.	8.6	44.7	20.2	78.2	4.17	6.75	0.000	12.4	47.3	25.6	62.8	4.60	11.79	0.000
Slaughter^b b T-SF and SS-SF.	10.6	54.1	23.7	80.7	3.92	6.73	0.000	11.2	60.6	27.6	51.0	5.27	14.96	0.000

7-19 years	n = 93							n = 92
%BF DXA	11.3	47.2	25.5					17.2	52.5	33.3
Equation 1	11.6	44.0	26.0	91.5	2.66	-0.79	0.370	17.2	45.3	33.3	79.1	3.42	0.45	0.806
Equation 2	12.2	44.6	26.2	90.6	2.78	-0.75	0.423
Equation 3	10.6	43.3	25.6	91.5	2.65	0.03	0.972
Deurenberg^c c T-SF and B-SF.	10.2	31.4	19.5	80.2	4.05	-6.85	0.000	13.8	35.8	23.6	67.6	4.25	3.70	0.097
Deurenberg^d d T-SF, B-SF SI-SF, and SS-SF.	11.3	34.5	20.8	84.8	3.55	-6.54	0.000	13.8	40.1	26.1	67.0	4.29	4.97	0.023

4-10 years	n = 29							n = 33
%BF DXA	15.6	44.7	28.9					17.2	45.8	33.1
Equation 1	17.0	39.9	29.5	88.9	2.82	-2.14	0.335	17.2	44.9	32.3	82.1	3.25	2.11	0.430
Equation 2	17.9	40.2	29.8	88.5	2.86	-3.65	0.128
Equation 3	17.6	40.8	29.5	90.2	2.64	-2.59	0.219
Dezenberg^e e Weight.	12.7	36.1	25.3	68.1	4.77	-0.57	0.888	12.9	36.4	25.5	62.9	4.65	10.48	0.002
Dezenberg^f f Weight and T-SF.	15.2	36.2	25.2	77.4	4.02	0.42	0.892	11.3	38.4	26.4	79.8	3.43	7.67	0.002
Dezenberg^g g Weight, T-SF, and gender.	13.1	34.2	23.6	77.7	3.99	2.50	0.385	13.8	38.5	27.5	79.8	3.43	3.95	0.147
Dezenberg^h h Weight, T-SF, gender, and ethnicity.	12.5	33.6	23.0	77.7	4.00	3.32	0.237	12.8	37.8	26.7	79.8	3.43	5.28	0.046

7-13 years	n = 66							n = 53
%BF DXA	12.0	44.7	27.3					17.2	52.5	33.0
Equation 1	11.6	41.8	27.6	87.1	2.89	0.17	0.900	17.2	45.3	32.3	83.4	3.36	-0.48	0.822
Equation 2	12.2	42.5	27.8	85.6	3.05	-0.03	0.982
Equation 3	10.7	43.0	27.3	87.8	2.81	0.82	0.522
Huangⁱ i Age.	0.9	42.5	24.2	61.9	4.97	13.51	0.000	5.6	46.2	28.2	63.5	4.96	14.25	0.000
Huang^j j Age and gender.	-1.6	40.7	21.9	64.4	4.81	14.85	0.000	9.7	47.9	31.0	63.5	4.96	11.10	0.000
Huang^k k Age, gender, and height.	4.1	40.8	23.9	58.9	5.16	11.98	0.000	-6.5	44.5	22.7	67.3	4.70	19.47	0.000

8-17 years	n = 85
%BF DXA	11.3	47.2	25.1
Equation 1	11.6	44.0	25.6	91.6	2.59	-0.64	0.478
Equation 2	12.2	44.6	25.7	90.7	2.72	-0.49	0.603
Equation 3	10.6	43.3	25.2	91.5	2.59	0.25	0.776
Stevens^l l Age, race, weight, height, waist, and T-SF.	20.6	49.2	31.8	83.4	3.63	-10.89	0.000

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[1] * Corresponding author. E-mail:lortiz@correo.xoc.uam.mx (L. Ortiz-Hernández).