Body composition. Body composition models Fluid-metabolism ECF. Body composition models Elemental. Body composition models Anatomic. Molnár Dénes.

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1 Body composition models Fluid-metabolism Fat Body composition ECF Molnár Dénes BCM ICF ICS ECS FFM Body composition models Anatomic Fat NSMST SM Body composition models Elemental Miscellaneous Calcium Nitrogen Hydrogen Carbon FFM Bone Oxygen 1

2 Body composition models Chemical Fat Water FFM Protein Minerals 2

3 Terminology Technical term Body fat Essential lipids Fat tissue Lean body mass (LBM) Fat free mass (FFM) Total body water (TBW) Intracellular water (ICW) Extracellular water (ECW) Definition The total fat extractable by ether (90% is nonessential) Lipids in the bone marrow & in cell membranes, phospholipids in the neurones Fat (80-85%) + cellular & extracellular non-lipid structures The body mass without fat tissue LBM + non-lipid structures of the fat tissue The total water content of the body Water in the cells Plasma + intersticial water Most frequently used indexes Wt/ht weight/height Wt/ht 2 weight/height 2 BMI or Quatelet index Ht 3 /wt height 3 /weight Ponderal index Wt/ht 3 weight/height 3 Rohrer index Act. Wt/50th ct. Wt. For age, sex, ht 100 Rel. Body weight Act. Wt/act ht 50th ct. Ht/50th ct. Wt 100 Shukla index 3

4 Published equations used to calculate body fat in adolescents from skinfold thickness Published equations used to calculate body fat in adolescents from skinfold thickness Authors Population Equations Siri, 1961 Lohman et al, 1984 Weststrate & Deurenberg, 1989 Brook, 1971 Durnin & Rahaman, 1967 Durnin & Womersley, 1974 Johnston et al, 1988 Adults Prepubescent children y (modification of Siri equation) 1-11 y (predicted from equations for adolescents) y y 8-14 y M and F: Fat (%) = 495/D 450 M and F: Fat (%) = 530/D 489 F: Fat (%) = [ (Age 10)] / D [514 8 (Age 10)] M: Fat (%) = [ (Age 2)] / D [ (Age 2)] F: D = (LOG sum of 4 skinfolds) M: D = (LOG sum of 4 skinfolds) F ( y): D = (LOG sum of 4 skinfolds) M ( y): D = (LOG sum of 4 skinfolds) F ( y): D = (LOG sum of 4 skinfolds) M ( y): D = (LOG sum of 4 skinfolds) F: D = (LOG sum of 4 skinfolds) M: D = (LOG sum of 4 skinfolds) Deurenberg et al, 1990 Sarría et al, 1998 Sloan et al, 1962 Wilmore & Behnke, 1970 Pubertal F: 13.1 ± 0.15 y Pubertal M: 13.8 ± 0.21 y Post-pubertal F: 16.8 ± 0.36 y Post-pubertal F: 17.5 ± 0.39 y y Young women Young women F pubertal: D = (LOG sum of 4 skinfolds) (age 10-3 ) M pubertal: D = (LOG sum of 4 skinfolds) (age 10-3 ) F post-pubertal: D = (LOG sum of 4 skinfolds) M postpubertal: D = (LOG sum of 4 skinfolds) M ( ): D = (LOG sum of 4 skinfolds) M ( ): D = (LOG sum of 4 skinfolds) F: D = suprai tric F: D = subsc tric thigh Published equations used to calculate body fat in adolescents from skinfold thickness Slaughter et al, 1988 Lean et al, 1996 Bray et al, 2001 Prepubertal F: 10.0 ± 1.0 y Prepubertal M: 9.8 ± 1.3 y Pubertal F: 11.4 ± 1.9 y Pubertal M: 12.2 ± 1.4 y Post-pubertal F: 15.3 ± 1.6 y Post-pubertal M: 15.8 ± 1.6 y y 10 y All F: Fat (%) = 1.33 (tric+subsc) (tric+subsc) Prepubertal M: Fat (%) = 1.21 (tric+subsc) (tric+subsc) Pubertal M: Fat (%) = 1.21 (tric+subsc) (tric+subsc) Post-pubertal M: Fat (%) = 1.21 (tric+subsc) (tric+subsc) All F when (tric+subsc) > 35mm: Fat (%) = (tric+subsc) All M when (tric+subsc) > 35mm: Fat (%) = (tric+subsc) F: Fat (%) = 0.61 (tric+calf) +5.1 M: Fat (%) = (tric+calf) + 1 F: Fat (%) = BMI tric Age 5.9 M: Fat (%) = BMI tric Age 20 M and F: Fat (%) = subsc thigh biceps calf M and F: Fat (%) = subsc biceps suprai tric Agreement between body fat % assessed by the Durnin equation and DXA measurement in adolescent girls Difference in body fat (DXA- Durnin et al.) (%) y = x r = 0.50 (p < 0.001) Body fat by equation of Durnin et al. (% ) Mean+2SD (Rodríguez G et al. Eur J Clin Nutr 2005; 59: ) Mean Mean-2SD 4

5 Agreement between body fat % assessed by the Slaughter equation and DXA measurement in adolescent boys Agreement between body fat % assessed by the Brook equation and DXA measurement in adolescent girls Difference in body fat (DXA- Slaughter et al. TS) (%) y = x r = 0,02 (p: NS) Body fat by equation of Slaughter et al. TS (%) Mean+2SD Mean Mean-2SD Difference in body fat (DXA- Brook) (%) y = x r = (p: NS) Body fat by equation of Brook (%) Mean+2S D Mean Mean-2SD (Rodríguez G et al. Eur J Clin Nutr 2005; 59: ) (Rodríguez G et al. Eur J Clin Nutr 2005; 59: ) Agreement between body fat % assessed by the Slaughter equation and DXA measurement in adolescent girls Difference in body fat (DXA- Slaughter et al. TS) (%) y = x r = 0.01 (p: NS) Body fat by equation of Slaughter et al. TS (% ) Mean+2SD Mean Mean-2SD Body fat composition measurement Clinical and epidemiologic studies Anthropometry Bioelectrical impedance DXA Air displacement pletismography (BodPod) (Rodríguez G et al. Eur J Clin Nutr 2005; 59: ) 5

6 Anthropometry training Triceps skinfold measurement For measurement of triceps skinfold the observer stands behind the adolescent and picks up the skinfold about the midpoint mark over the triceps muscle, with the fold running downward along the midline of the back upper arm. The caliper jaws must be applied at right angles to the neck of the fold just below the finger and thumb over the midpoint mark. 6

7 Most frequently measured parameters Weight Height Skinfolds biceps triceps subscapular suprailiac thigh calf Circumferences relaxed arm flexed arm waist hip upper thigh Skinfolds Holtain caliper Instruments used Weight Instruments used This is the balance we use in field studies Seca 780, capacity: 150 kg, wt. 6.6kg, graduation: 100 g Seca 767, capacity: 200kg, wt: 6.8 kg, graduation: 100 g, retrofitted with Seca measuring rod Seca 766, capacity: 200kg, wt: 6.8 kg, graduation: 50g < 150 kg, 100 g > 150 kg 7

8 Height Instruments used The Seca measuring rodusedbyusinfield studies Other suggestions? Seca 225, range cm, graduation: 1 mm, wt: 7 kg Seca 220 rod with Seca 767 balance, range: cm, graduation: 1 mm, wt: 700 g Instruments used Circumferences non-elastic tape (metal tape?) Range: cm, graduations: 1 mm, wt: 50 g 8

9 Body composition Bioelectric impedance analysers Impedance frequency Position Other measuremen ts Price Disatvantage, advantage Anthropometry which equation? BIA DEXA BodPod TANITA BC-418 MA HUMAN IM PLUS II 4-probes AKERN BIA khz 5, 10, 50, 100 khz 50 khz Standing Lying Lying Weight, segmental analysis Resistance, Reactance, Phase angle, segmental analysis Resitance, reactance Short measuring time, no equations can be developed, accuracy of the balance? Longer measuring time, electrodes and balance should be purchased Longer mesuring time, electrodes and balance should be purchased, easy to carry!! 9

10 InBody 720, Biospace Multifrequency, segmental analysis, etc price: Reliability of the measurement Interobserver variation Intraobserver variation Biological variation Technical error of measurement (TEM) Technical error of measurement TEM) Ulijaszek SJ & Kerr DA Br J Nutr 82: , 1999 TEM can be calculated by the equation below if two or more observers performes repeated measures on the same individual and the inter- or intraobserver differences are substituted into the equation TEM = (summa D²)/2N (in case of two measures & two observers), the equation is more complex if there are more repeated measures and more than two observers. D=difference between repeated measures N=number of measured persons %(relative)tem %TEM = (TEM/mean) 100 %total TEM = (total TEM)/mean) 100 The rel. TEM admits the comparison of the errors of two measures with different absolute values. 10

11 Coefficient of reliability (R) R = 0-1 R=1- (total TEM 2 / SD 2 ) SD 2 = the total intersubject variance Ez a legszélesebb körben használt mutatója az antropometriai mérések precizitására. If R > 0.95, then > 95% of the variance is not due to the measurement error. 11