Clinical Assessment of Body Composition

Marta Van Loan, Ph.DUSDA, Western Human

Nutrition Research Centermvanloan@whnrc.usda.gov

Objectives Overview and understanding of body

composition and body compartments.

Overview and understanding of methods.

Application of methods assessment: examples with specific disease conditions.

What Compartments Can We Measure? 1 – Compartment

Body Weight 2 – Compartment

Fat Mass (FM) & Fat-Free Mass (FFM) Total Body Water (TBW) & Extracellular

Fluid (ECF) 3 – Compartment

FFM, TBW, FM FFM, Bone Mineral Content (BMC) FM

What Compartments Can We Measure? 4 – Compartment

FFM, TBW, BMC & FM 6 – Compartment

Elemental Analysis N, C, Ca, Na, Cl, and K

4 – Compartment Model

FAT MASS

FAT-FREE

MASS

Mineral

Protein

WaterB

ody Weight

Methods for Body Composition Assessment IN VIVO Neutron Activation Analysis

Elemental Analysis Computed Tomography

Site Specific images - IAAT Magnetic Resonance Imaging

Site Specific images - IAAT Densitometry – reference method

Hydrostatic Weighing, BodPod Dual Energy X-ray Absorptiometry (DXA)

Methods for Body Composition Assessment Tracer Techniques – reference

method 2H, 3H, 18O, NaBr

Electrical Techniques BIA (single & multi- frequency) BIS – Cole-Cole Model

Skinfolds & Anthropometric Body Mass or Weight

Principles of Methods

Bod Pod – body density Archimedes

Density of the body is determined – reference method Equations are used to convert body density to body fat Size Limitations – 450 pounds

Dilution Techniques Deuterium (2H) exchanges with H2O – reference method NaBr dilution doesn’t cross cell membrane – ECF space Requires pre- and post- dilution specimen (serum, urine) C1 x V1 = C2 x V2

Principles of Methods

Bioelectrical Impedance (BIA) Water and electrolytes are conductors Fixed frequency (50kHz) transmitted through body Measures Resistance, Capacitance, Phase Angle Phase = cellular health and/or cellular death Equations are used to convert resistance measures

to estimates of fat-free mass (FFM) Multiple Frequency Impedance (MFBIA)

Frequencies vary from 5 kHz – 1MHz Use of prediction equations - not independent of

TBW Cole-Cole model

BIA Measurement

Principles of Methods

Dual Energy X-ray Absortiometry (DXA) X-ray is filtered into 2 energies Measures Bone Mineral Content (BMC) Bone Free Soft Tissue (BFST) BMC + BST = FFM Distribution of Fat and Lean Tissue Special Region Of Interest (ROI) for Specific

Sites Size Limitations

DXA Lumbar Spine Measurement

DXA for Whole Body Composition

Clinical Use of Body Composition Anorexia & Obesity Renal Failure Liver Disorders: Ascites Chronic Obstructive Pulmonary Disease Cancer & AIDS associated wasting Burns & Trauma Congestive Heart Failure Spinal Cord Injuries Osteoporosis

BIS for Extra- and Intracellular Fluid, Total Body Water, and FFMVan Loan et al. Human Body Composition, 1993

Mean STD

ECF – NaBr 14.6 + 2.1

ECF – BIS 14.6 + 2.2

TBW – D2O 33.6 + 5.6

TBW – BIS 33.5 + 5.5

ICF – BIS 19.1 + 4.0

ICF - BIS 19.2 + 3.4

FFM – D20 45.5 + 7.3

FFM – BIS 45.5 + 7.2

Body Composition in AIDS Wasted Men on Gonadal Hormone Replacement

Therapy Van Loan et al. AIDS 1999; 13: 241-248

18 men 21-d controlled in-patient intervention

followed by 12 wk out-patient therapy Nitrogen balance from 21 d in-patient

control period was reference method DXA, D2O, and BIS as experimental

methods

Body Weight and FFM after 12 wk Nandrolone Deconate Therapy

Baseline 6 Weeks 12 Weeks

Weight,kg 73.3 8.8 77.0 6.0 78.2 10.1

DXA(FFM),kg 61.2 6.2 63.0 5.4 64.0 6.9

D2O(FFM),kg 60.6 6.7 59.9 3.0 64.7 8.2

BIS(FFM),kg 56.5 + 6.8 59.3 + 4.9 61.8 + 6.6

Cumulative Changes at 12 Weeks

6 Weeks 12 Weeks

Weight, kg 3.7 4.9

Lean Tissue Accretion,kg 2.5 5.0

DXA – FFM, kg 1.8 2.8

D2O – FFM, kg - 0.7 4.1

BIS – FFM, kg 2.8 5.3

Fluid Changes During Pregnancy

Van Loan et al. J Appl Physiol 1995; 78 : 1037-1042

10 Women tested at Baseline, 8-10wk, 24-26 wk, 34-36 wk, 4-6 wk PP.

D2O & NaBr dilutions. Bioimpedance Spectroscopy (BIS) with

Cole-Cole Model. BIS spectra for 18 logarithmically spaced

frequencies Frequencies from 5 to 548 kHz.

Comparison Between Dilution and BIS Estimates of TBW and ECF

Baseline

8-10 wk

24-26 wk

34-36 wk

4-6 wk PP

TBWD2O33.2

± 4.6

33.1

± 5.1

36.1

± 4.1

38.7

± 3.9

33.4

± 3.8

TBWBIS31.6

± 6.2

32.0

± 5.2

35.1

± 5.6

38.3

± 5.0

33.2

± 4.3

ECFNaBr15.2

± 1.3

18.1

± 1.9

20.7

± 3.6

18.3

± 3.4

ECFBIS16.9

± 2.3

16.0

± 2.3

19.4

± 3.1

21.8

± 2.4

17.0

± 2.4

Potential Uses on MethodsFound in Literature

Bod Pod FFM & FM

Adults Infant model – tested

DXA BMC, BMD, FFM,and FM Tissue Distribution

CT and MRI Site specific tissue analysis

Potential Uses on MethodsFound in Literature

BIA FFM & FM

Adult and Pediatric Dialysis Survival

Cancer, peritoneal dialysis, malnutrition, obesity Congestive Heart failure

MFBIA or BIS FFM, FM, TBW, ECF Pregnancy, HIV+ wasting

Which Method to Use? Depends on compartment of interest. Availability of techniques. Technical training of staff. Condition of patient. Location where assessment will be

done: Laboratory / clinic Field / remote site