- Click here for explanation of classification scheme.

To compare measured resting energy expenditure with calculated REE using actual, ideal, and adjusted body wt in the HBE and the IJE in obese females.

1. Understand and give written consent

2. Diseases in subjects that were allowed: heart disease, endocrine problems, diabetes mellitus, HIV/AIDS, or other major diseases affecting immune system function

3. Medications allowed: any drugs known to affect metabolic rate.

1. Refusal to consent

2. Not meeting inclusion criteria

3. Participants who smoked more than 6 cigarettes per day or exercised heavily

4. Pregnant or lactating women

Definitions:

“Steady state”- 3 consecutive 30s VO2/L readings were within 0.01L and hwere VO2 values were no longer dropping.

Obesity of defined as greater than 125% ideal body wt

Terms:

HBE-the Harris-Benedict equation

IJE-the Ireton-Jones equation

MREE-measured resting energy expenditure

IBW-ideal body weight

ABW-actual body weight

AdjBW-adjusted body weight

“RMPSE”-root mean squared prediction error

Anthropometrics

Ht measured ? yes

Wt measured ? yes

Fat-free mass measured? yes

Lean mass, fat mass, BMI

CLINICAL:

Monitored heart rate? yes

Body temperature? yes

Medications administered? no

Resting energy expenditure:

IC type: open circuit

Equipment of Calibration: yes

Coefficient of variation using std gases: yes

Rest before measure (state length of time rested if available): 30 min

Measurement length: 1 continuous measure

Steady state: the measurements was completed when the participant reached a stead state

Fasting length: 12h; : none during measurements

Exercise restrictions XX hr prior to test? 24h;

Room temp: 21-22 °C

No. of measures within the measurement period: continuous measurements

Were some measures eliminated? no

Were a set of measurements averaged? no

Coefficient of variation in subjects measures? no

Training of measurer? no

Subject training of measuring process? no

DIETARY

All subjects fast 12 h before IC measurements. Dietary intake prior to IC studies were not controlled

Intervening factor:

Menstrual cycle was not considered.

Blinding used (if applicable): None

Statistical Analysis

Descriptive statistics

Pearson’s correlation

Paired t test

Stepwise linear regressions analysis

RMPSE was calculated to determine how close calculated REE values compared to the MREE for each person. The smaller the RMSPE, the closer the calculated value is to the measured values. RMSPE is a good indicator of the accuracy of the prediction equations for each person, rather than for the sample as a whole.

Outcome(s) and other measures

1. Measured REE

2. Predicted RMR using: HBE (using IBW, ABW, AdjBW) and IJE

3. Independent variables of weight, height, age, BMI,and fat-free mass, fat mass

Blinding Used:  None

N= 19 women, aged 19-38 yr   (29.5 +/-5.38 y)

Healthy, premenopausal , young, Caucasian women

17 were nonsmokers, 2 smoked less than 6 cigarettes/d

ANTHROPOMETRIC (mean ± SD)          

	Mean ± SD	Range
Ht,cm	166 ±4.1	158.5 - 175.9
Wt,kg	98.0 ± 23.4	70.9 - 159.1
BMI	35.3 ± 8.4	26.0 - 59.1
FM,kg	41.3 ± 14.7	24.8 - 81.8
FFM,kg	56.7 ± 9.3	45.8 – 77.3
%body fat	41.2 ± 5.0	31.6-51.4
MREE	1359.2 ± 252.4	941.0 – 1775.0
HBE(IBW)	1416.3 ± 50.3	1333.0 – 1514.0
HBE(ABW)*	1755.4 ± 217.9	1530.0 – 2346.0
HBE(AdjBW)**	1505.5 ± 75.6	1385.0 – 1661.0
Ireton-Jones Eqn*	1868.5 ± 257.1	1571.0 – 2541.0

*significantly different from MREE at p<0.0001 level

** significantly different from MREE at P<0.05 level

There was no significant difference between MREE and REE calculated with HBE using IBW.  REE calculated with HBE adjusted and actual body wt were significantly higher than MREE by 11% (p<0.05) and 29% (p<0.0001), respectively; REE calculated with IJE was significantly higher than measured REE by 37% (P<0.0001)

Root Mean Squared Prediction Error (mean ±SD)

HBE using adjusted body wt had the lowest RMSPE. Stepwise regressions analysis resulted in the following prediction equation for REE:

REE= 17.5(LMB) + 368.7,

       R=0.64

“Using ABW in the HBE to estimate energy expenditure in obese women should be avoided because it consistently overestimates energy requirements. Using ABW in the equation assumes the excess wt is the same composition as that of a lean person. Using ABW does not compensate for the considerable amount of FFM and the slowed metabolic activity of adipose tissue.”

“HBE using AdjBW was greater than MREE; however, the difference (11%) was much less than the difference between HBE using ABW (29%) and the IJE (37%).”

“There was no difference between HBE using IBW and measured REE; however, RMSPE values indicate that HBE using AdjBW was the most accurate predictor of measured REE, followed closely by HBE using IBW.”

“The IJE overestimated REE of our participants, and had the highest RMSPE value, indicating that it was the least accurate of the equations used.”

“The present study provides evidence that using HBE with IBW or AdjBW are better than the IJE or HBE using ABW to use when estimating REE in obese women.”

Industry:	Wyeth-Ayerst Pharmaceuticals, NeoRX Corporation Pharmaceutical/Dietary Supplement Company: Other:
University/Hospital:	Washington State University, University of Dayton

Strengths:

• Compared MREE with HB with IBW, ABW and AdjBW.
• Appropriate, sophisticated statistics.
• Smoking status, physical activity were monitored.
• Conclusions were supported by results, and were considered with its small sample size.
• A thorough discussion of different equations based on study results.

Generalizability/Weaknesses:

• Relatively small sample size for validations study.  Results only applied to healthy, young, premenopausal obese women.
• Limitations were not fully addressed.