Physiological models of body composition and human obesity

1743-7075-6-7 1743-7075 Correction Physiological models of body composition and human obesity Levitt G David levit001@umn.edu Heymsfield B Steven Steven_Heymsfield@Merck.Com Pierson N Richard Jr RNP1@Columbia.edu Shapses A Sue shapses@aesop.rutgers.edu Kral G John jkral@downstate.edu

Department of Integrative Biology and Physiology, University of Minnesota, 321 Church Street SE, Minneapolis, MN 55455, USA

Merck & Co, 126 E. Lincoln Avenue, PO Box 2000, RY34-A238, Rahway, NJ 07065-0900, USA

St. Luke's-Roosevelt Hospital, Columbia University College of Physicians and Surgeons, NY Body Composition Unit, 114th street and Amsterdam Avenue, NY, NY 10025, USA

Department of Nutritional Sciences, Rutgers University, 96 Lipman Drive, New Brunswick, NJ 08901, USA

Department of Surgery, SUNY Downstate Medical Center, Box 40, 450 Clarkson Avenue, Brooklyn, NY 11203, USA

Nutrition & Metabolism 1743-7075 2009 6 1 7 http://www.nutritionandmetabolism.com/content/6/1/7 19220892 10.1186/1743-7075-6-7 13 2 2009 16 2 2009 16 2 2009 2009 Levitt et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Correction to Levitt DG, Heymsfield SB, Pierson Jr RN, Shapses SA, Kral JG: Physiological models of body composition and human obesity. Nutrition & Metabolism 2007, 4:19

Correction

Since publication of our first article 1 we have noticed that the following corrections needed to be made. There is an error in the calculation of the body fat in the original version of this article. The tritium distribution space was not properly corrected for non-aqueous hydrogen exchange and water density resulting in estimates of percent body fat that are about 2% less then the correct percent. This produces small errors in the regression relations for the prediction of body fat from BMI or body density described originally in Tables 3, 4, 5, 6, 7, 8 and 9. The corrected tables (calculated using TBW = 3H2O × 0.96 × 0.994) are provided.

Table 3

Caucasian males: Dependence of fat fraction on age for two BMI ranges.

BMI Range

Ave age (SD)

Age range

Ave BMI

Ave Fat Fraction

18 – 24

21.86 (2.44)

18 – 25

22.19 (1.08)

0.1193 (.046)

29.94 (2.36)

26 – 33

22.12 (1.34)

0.134 (.048) (NS)

52.83 (19.42)

34 – 84

22.39 (1.31)

0.173 (.057) (p < .01)

24 – 44

25.94 (2.66)

21 – 30

27.64 (4.00)

0.188 (.084)

38.17 (5.07)

31 – 48

27.42 (3.96)

0.211 (.072) (NS)

66.25 (10.69)

49 – 97

27.93 (3.41)

0.284 (.075) (p < .01)

The p values are for comparisons to the closest younger age group.

Table 4

Caucasian females: Dependence of fat fraction on age for three BMI ranges.

BMI Range

Ave age (SD)

Age range

Ave BMI

Ave Fat Fraction

17 – 22

24.95 (3.41)

18 – 30

20.00 (1.38)

0.219 (.045)

38.04 (5.87)

30 – 49

20.60 (1.07)

0.241 (.056) (p < .05)

63.32 (11.18)

49 – 89

20.55 (1.01)

0.298 (.053) (p < .01)

22 – 25.9

26.14 (4.72)

18 – 33

23.30 (1.03)

0.26 (.049)

39.12 (4.91)

33 – 51

23.45 (1.05)

0.30 (.055) (p < .01)

68.12 (10.47)

52 – 88

24.12 (1.15)

0.36 (.059) (p < .01)

26 – 56

34.94 (6.198)

21 – 45

31.19 (6.12)

0.408 (.074)

54.0 (4.69)

46 – 61

31.72 (5.89)

.428 (.056) (NS)

70.49 (6.87)

62 – 90

29.36 (2.68)

0.414 (.053) (NS)

The p values are for comparisons to the closest younger age group

Table 5

Ethnic dependence of BMI versus fat fraction for males.

Age range (ave)

BMI range (ave)

Ave Fat Fract. (SD)

Caucasian

129

20 – 57 (37.4)

22 – 34 (25.42)

0.321 (0.071)

Black

20 – 52 (37.8)

20 – 34 (26.57)

0.328 (0.074) (NS)

Hispanic

20 – 60 (36.1)

20 – 34 (25.40)

0.311 (0.09) (NS)

Puerto Rican

20 – 52 (35.7)

20 – 30 (26.18)

0.348 (0.058) (p < .05)

Caucasian

153

23 – 53 (35.41)

17 – 25 (21.72)

0.257 (.061)

Asian

23 – 53 (36.7)

17 – 28 (21.25)

0.282 (.066) (p = 0.07)

The age range of the Caucasians was adjusted to match the age range of the comparison group. The p values are for comparisons between the ethnic group and Caucasians.

Table 6

Ethnic dependence of BMI versus fat fraction for females.

Age range (ave)

BMI range (ave)

Ave Fat Fract. (SD)

Caucasian

129

20 – 57 (37.4)

22 – 34 (25.42)

0.321 (0.071)

Black

20 – 52 (37.8)

20 – 34 (26.57)

0.328 (0.074) (NS)

Hispanic

20 – 60 (36.1)

20 – 34 (25.40)

0.311 (0.09) (NS)

Puerto Rican

20 – 52 (35.7)

20 – 30 (26.18)

0.348 (0.058) (p < .05)

Caucasian

153

23 – 53 (35.41)

17 – 25 (21.72)

0.257 (.061)

Asian

23 – 53 (36.7)

17 – 28 (21.25)

0.282 (.066) (p = 0.07)

The age range of the Caucasians was adjusted to match the age range of the comparison group. The p values are for comparisons between the ethnic group and Caucasians.

Table 7

Comparison of linear (eq. (16)) and non-linear (eq. (9)) regression expressions for predicting body fat fraction from BMI and age.

Subjects

± Age

Linear

Non-linear Model I

MSR

BMI₀

f₁

MSR

Male Caucasians

-.166

.0141

----

0.00404

17.20

.624

----

.00409

Yes

-.218

.0129

.00207

0.00263

19.15

.500

.00194

.00287

Male Caucasian +Hispanic+Black

-.145

.0134

-----

.00380

16.71

.594

----

.00385

Yes

-.206

.0127

.00182

0.00270

18.73

.496

.00172

.00288

Male Asian

Yes

-.156

.0126

.00169

0.00201

15.72

.438

.00169

.00212

Male Puerto Rican

Yes

-.155

.0119

.00163

0.00189

17.84

.536

.00150

.00188

Female Caucasian

0.0409

.0113

-----

0.00391

13.50

.739

-----

.00314

Yes

-.0240

.0104

.00186

0.00281

14.39

.635

.00151

.00244

Female Caucasian +Hispanic+Black

0.0494

.0109

------

.00351

13.50

.728

-----

.00276

Yes

-.0160

.0104

.00169

0.00260

14.37

.642

.00132

.00222

Female Asian

Yes

-.0903

.0153

.00122

0.00137

12.38

.573

.00122

.00140

Female Puerto Rican

Yes

0.0718

.00919

.000947

.00159

12.82

.639

.000737

.00142

The regression parameters (either a, b and c; or BMI0, f1 and c) and the mean square residual error (MSR) for the different ethnic groups are listed.

Table 8

Prediction of fat fraction from BMI for Caucasian + Black + Hispanic subjects.

Subjects

Linear

Model I

Model II

MSR

f₁

BMI₀

MSR

f₁

f₀

BMI₀

MSR

Male: 18 – 89

-.145

.0134

.0038

.594

16.71

0.00385

.647

.129

22.00

0.00377

Male: 18 – 31

-.201

.0134

.00273

.543

19.39

0.00315

.706

.118

23.78

0.00261

Male: 32 – 50

-.133

.0119

.00303

.505

16.54

0.00312

.619

.153

23.54

0.00281

Male: 51 – 89

-.126

.0136

.00310

.628

16.28

.00299

.661

.167

21.43

0.00283

Female: 18 – 90

+.0494

.0109

.00351

.728

13.50

.00276

.745

.220

19.65

0.00272

Female: 18 – 31

-.00685

.0116

.00237

.695

13.99

.00225

.774

.214

21.30

0.00181

Female: 32 – 50

+0.0700

.00963

.00306

.723

13.86

.00212

.737

.208

19.71

0.00209

Female: 51 – 90

+0.106

.0101

.00225

.681

11.57

.00210

.682

.249

18.28

0.00210

Model parameters and mean square residual error (MSR) for Model I, Model II and Linear fit are listed.

Table 9

Prediction of fat fraction from body density for Caucasian + Black + Hispanic subjects.

Subjects

f₀

f₁

d₀

d₁

MSRls

MSRsiri1

MSRsiri2

MSRbro

Male: 18 – 89

4.63

4.208

0.129

0.647

1.0678

0.954

.000481

.000693

.000711

0.000553

Male: 18 – 31

4.912

4.475

0.118

0.706

1.0695

0.948

.000402

.000536

.000597

0.000532

Male: 32 – 50

4.559

4.141

0.153

0.619

1.061

0.958

.000457

.000723

.000614

.000562

Male: 51 – 89

4.231

3.821

0.167

0.661

1.0612

0.944

.000516

.000853

.000957

.000568

Female: 18 – 90

4.673

4.239

0.220

0.745

1.048

0.9376

.000640

.000813

.00202

.000662

Female: 18 – 31

4.779

4.339

0.214

0.774

1.050

.935

.000616

.00066

.00178

.000661

Female: 32 – 50

4.785

4.347

0.208

0.737

1.050

.941

.000538

.000653

.00191

.000576

Female: 51 – 90

4.606

4.175

0.249

0.682

1.041

.948

.000722

.00102

.00223

.000732

The parameters a and b are the optimal least square values (fat fraction = a/density – b), and f0 and f1 are the fat fractions used for the determination of d0 and d1 from the values of a and b. The mean square residual error for the least square fit (MSRls), the Siri Model I (MSRsiri1, eq. (13)) and Model II (MSRsiri2, eq. (14)) and the Brozek model (MSRbro, eq. (10)) are also listed.

Physiological models of body composition and human obesity Levitt DG Heymsfield SB Pierson RN Jr Shapses SA Kral JG Nutrition & Metabolism 2007 4 19 2082278 17883858 10.1186/1743-7075-4-19