Johnston et al estimated body density in children based on skinfold thickness measurements. The authors are from the University of Alberta in Edmonton.

Patient selection: children from 8 to 14 years of age



(1) gender

(2) biceps skinfold in mm

(3) triceps skinfold in mm

(4) subscapular skinfold in mm

(5) suprailiac skinfold in mm


body density of boys in g/cc =

= 1.166 - (0.070 * LOG10(SUM all 4 skinfolds))


body density of girls in g/cc =

= 1.144 - (0.060 * LOG10(SUM all 4 skinfolds))


NOTE: The authors report density in kg per cubic meter. It should be kg per liter. A cubic meter is 1,000 liters.


Once the density is known, then the percent body fat can be estimated using the equation of Lohman et al (above)



• The r-squared for boys was 0.492 and for girls was 0.452.

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