Adult Weight Management

Healthy Non-Obese Adults (2010-2012)

Citation:

Siervo M, Boschi V, Falconi C. Which REE prediction equation should we use in normal-weight, overweight and obese women? Clin Nutr. 2003; 22(2): 193-204.

PubMed ID: 12706138
 
Study Design:
Cross-Sectional Study
Class:
D - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:
  • To examine those predictive equations for energy expenditure that would permit more accurate resting energy expenditure estimates within a young female population
  • To revise the chosen equations to adjust individual body mass index (BMI) to the subject's nutritional state (normal weight, overweight, obese)
  • To examine how weight loss might influence the REE prediction of anthropometrical equations after a period of dietary treatment.
Inclusion Criteria:
  • Low level of physical activity
  • No signs of physical or mental disorders
  • No pharmacological treatment
  • Not on particular diet
  • Maintained a steady weight for at least two months (±3kg)
  • Low level of physical activity
  • No pharmacological treatment.
Exclusion Criteria:
  • Unhealthy subjects
  • Refusal to consent.
Description of Study Protocol:

Design

Cross-sectional study with a before-after weight loss subset.

Statistical Analysis

  • ANOVA was performed to examine the statistical significant differences among three BMI groups
  • Bland's and Altman's indications were taken into account for the statistical analysis for comparison of the REE measured and the prediction equations
  • Paired T-test was used to determine the statistically significant differences between the measured and predicted REE derived from the applied equations
  • The ±95% CI and Bland's and Altman's analysis were used for comparison between measured and predicted REE, due to the limit of the mean
  • Pearson coefficient correlation R between measured and predicted REE was calculated
  • Stepwise multiple regression was performed using anthropometrical measurements as independent variables and REE as the dependent variable to develop a REE prediction equation.

Study Protocol

  • REE was measured with IC and was compared with the principal prediction equations [Harris and Benedict, Owen, Mifflin St. Jeor, WHO, Bernsteine and Robertson and Reid, and one derived from current study (OUR)]
  • OUR equation: 11.5wt(kg) + 542.2
  • An additional REE measurement was performed on patients that had lost 5% or more of the initial body weight due to a sound low-calorie diet
  • Subjects were separated into three groups according to their BMI:
    • BMI 25 or less: Normal weight
    • 25 to 30 BMI: Overweight
    • BMI 30 or more: Obese
  • Steady state: RQ, oxygen consumption, minute ventilations were stable for at least five minutes.

Anthropometrics

  • Height measured: Yes
  • Weight measured: Yes
  • Fat-free mass measured: Yes
  • Body surface area (BSA), waist and hip ratio (WHR), BMI: Yes.

 Clinical

  • Monitored heart rate: No
  • Body temperature: No
  • Medications administered: No.

Resting Energy Expenditure

  • IC type: Canopy system
  • Equipment of calibration: Yes
  • Coefficient of variation using STD gases: Yes; ±3%
  • Rest before measure (state length of time rested if available): 20 minutes
  • Measurement length: 25 to 45 minutes
  • Steady state: Evaluate if mention of initial acclimatization and then continuous monitoring throughout measurement, if appropriate
  • Fasting length: 12 hours
  • Exercise restrictions XX hours prior to test: 24 hours
  • Room temperature: 25.0°C±0.5°C
  • Number of measures within the measurement period: Not specified
  • Were some measures eliminated: No
  • Set of measurements averaged: Not specified.
  • Coefficient of variation in subjects measures: No
  • Training of measurer: No
  • Subject training of measuring process: No. 

Dietary

Two-hour fast; food intake was not standardized prior to the IC study.

Intervening Factors

  • Subjects slept for at least eight hours
  • Were kept from smoking, sweet beverages, coffee, tea and drugs for at least 12 hours
  • Refrained from doing physical activity in the 24 hours preceding the morning of the measurements.

Statistical Tests

  • ANOVA
  • Paired T-test
  • Pearson coefficient correlation
  • Stepwise multiple regression.
Data Collection Summary:

Timing of Measurements

  • One measurement
  • Additional measurement in sub-sample (N=31) who had lost greater than or equal to 5% of initial body weight on a low-calorie diet:
    • Patients were re-evaluated every 15 days per month
    • Given no less than four weeks for losing 5% of initial weight.

Dependent Variables/Outcomes

  • Accuracy of REE estimates
  • Prediction equation (OUR equation)
  • Effect of weight loss on REE
    • IC type: Canopy system
    • Equipment of calibration: Yes
    • Coefficient of variation using STD gases: Yes; ±3%
    • Rest before measure (state length of time rested if available): 20 minutes
    • Measurement length: 25 to 45 minutes
    • Steady state: Measurements were made only when the subjects had reached a steady state condition (RQ, oxygen consumption, minute ventilation were stable for at least five minutes)
    • Fasting length: 12 hours
    • Exercise restrictions XX hour prior to test? 24 hours
    • Room temperature: 25.0°C±0.5°C
    • Number of measures within the measurement period: Not specified
    • Were some measures eliminated: No
    • Were a set of measurements averaged: Not specified
    • Coefficient of variation in subjects measures: No
    • Training of measurer: No
    • Subject training of measuring process: No
    • Monitored heart rate: No
    • Body temperature: No
    • Medications administered: No
    • Dietary: 12-hour fast, food intake was not standardized prior to the IC study
    • Intervening factors:
      • Subjects slept for at least eight hours
      • Were kept from smoking, sweet beverages, coffee, tea and drugs for at least 12 hours
      • Refrained from doing physical activity in the 24 hours preceding the morning of the measurement.

Independent Variables

  • Principal prediction equations (Harris and Benedict, Owen, Mifflin, WHO, Bernstein and Robertson and Reid, and one derived from current study (OUR equation: 11.5wt (kg) + 542.2
  • Anthropometric variables: Height (stadiometer to nearest 5cm); weight (in underclothes, precision balance scale to nearest 1kg), waist-hip ratio (WHR) [waist (inferior margin of last rib and the iliac crest), hip (tranchater level), BMI (kg/m2), body surface area]
  • Weight loss of 5% of initial weight in no less than four weeks.

Control Variables

Subjects were separated into three groups according to their BMI:

  • BMI=25: Normal weight
  • BMI=25 to 30: Overweight
  • BMI=30: Obese.
Description of Actual Data Sample:
  • Final N: N=157 females
  • Age: 18 to 35 years
  • Normal weight: 23.78±3.79 years
  • Overweight: 25.39±5.42 years
  • Obese: 23.82±5.49 years
  • Ethnicity: Italian 
  • Anthropometrics:
  Normal Weight (N=41) Overweight (N=58) Obese (N=58)
Height (cm) 160.58±5.7 161.27±6.86 161.45±6.75
Weight (kg)*** 58.73±6.04 71.37±7.77 90.88±10.55
BMI (kg/m2)*** 22.75±1.71 27.37±1.43 34.87±3.64
Waist circumference (cm)*** 71.48±6.78 82.46±7.21 97.89±8.9
Hip circumference (cm)*** 97.14±5.78 105.16±5.75 118.53±7.71
WHR*** 0.73±0.04 0.78±0.06 0.82±0.07
BSA (m2)*** 1.61±0.103 1.75±0.13 1.94±0.13

*** Statistical difference among normal weight, overweight and obese subjects on ANOVA test (P<0.001).

  • Location: University "Federico II," Naples, Italy.
Summary of Results:

REE

  • The mean numerical bias and the mean percentage bias estimates were 9.7 (under-estimation = -0.75%) and 8.81 (-0.76%) for Owen’s and OUR, respectively
  • In the overweight group, Bernstein’s equation and OUR proved to be the most accurate, reporting a mean numerical bias and a mean percentage bias of –11.15 (over-estimation= ­-0.93%) and -4.75 (­0.4%), respectively
  • Finally, in the third group of the obese subjects, the most reliable equation were Robertson and Reid’s and OUR with errors of -10.47 (­0.66%) and -1.28 (­0.1%), respectively. 

BMI Groups: Bias Percent ±95% CI  (Note: Negative number indicates and over-estimation.)

  Normal Overweight Obese
HB -16.06 to -9.44 -13.16 to -8.39 -10.27 to -4.98
OWEN -3.01 to 4.52 0.89 to 6.59 6.3 to 12.53
MIFFLIN -9.95 to -2.86 -7.78 to -2.7 -5.94 to -0.32
BERNSTEIN -7.8 to -0.51 -3.64 to 1.77 1.22 to 7.22
WHO -12.4 to -5.65 -12.04 to -7.06 -12.02 to -6.38
R/R -10.39 to -3.59 -7.87 to -2.91 -3.51 to 2.19
OUR -2.98 to 4.52 -3.03 to 2.21 -2.88 to 2.67
  • Normal weight group:
    • The ±95% CI of the MREE was 1,177.35 to 1,275.61
    • Owen’s equation and OUR stayed within such range, reporting REE prediction values of 1,203.04 to 1,230.41 and of 1,195.74 to 1,239.59, respectively
    • The same two equations showed a ±95% of the bias percentage within -3.01% to 4.53% and -2.98% to 4.52%.
  • Overweight group:
    • The ±95% CI for MREE was 1,313.69 to 1,402.92
    • Bernstein’s for the first and OUR for the second had REE prediction in this interval: ±95% CI of 1,352.81 to 1,386 and 1,339.54 to 1,387.57, respectively
    • Moreover, they showed a ±95% CI of the bias percentage of -3.64% to 1.77% and -3.03% to 2.21%.
  • Obese group:
    • The ±95% CI for MREE was 1,531.69 to 1,640
    • The most accurate equations were Robertson and Reids (1,566.42 to 1,626.42) and OUR (1,555.42 to 1,619.25) with ±95% CI of -3.51% to 2.19% and -2.88% to 2.67%, respectively. 

Stepwise Regression Analysis

Weight was a significant variable, resulting in the following equation: 542.2KG+11.5kg; R=0.59.

Bland-Altman Analysis 

  • Approach accurately evaluating the over-estimation, the under-estimation and the gradual development of the error as REE increased
  • The means of predicted and measured REE [measured + predicted)/2] plotted against the differences between the two procedures (i.e., measured – predicted) within two SDs from the mean (i.e., agreement lines) for all subjects (N=157) was reported for Harris-Benedict, Owen, Mifflin-St. Jeor, and Bernstein
  • Harris-Benedict (Bland-Altman):
    • HB ranged from an over-prediction of 96kcals to an under-prediction of 48kcals (two SDs); three individuals had over-predictions more than 96kcals and three individuals had under-predictions higher than 48kcal.
  • Owen (Bland-Altman):
    • Owen ranged from an over-prediction of 60kcals to an under-prediction of approximately 96kcals (two SDs); three individuals had over-predictions higher than 60kcals and six individuals had under-predictions higher than 96kcal.
  • Mifflin-St. Jeor (Bland-Altman):
    • MSJE ranged from an over-prediction of 86kcals to an under-prediction of approximately 57kcal (two SDs); three individuals had over-predictions more than 86kcal and six individuals had under-predictions more than 57kcal.
  • WHO/FAO/UNU (Bland-Altman):
    • WHO ranged from an over-prediction of 115kcal to an under-prediction of approximately 38kcal (two SDs); three individuals had over-predictions more than 115kcal and five individuals had under-predictions more than 38kcal.

Effect of Weight Loss

The effect of weight loss on the error of prediction was assessed in a group of 31 subjects. Only Owen’s equation maintained the error of prediction within acceptable limits. 

  • Harris-Benedict had a group mean over-prediction of 9.92% prior to weight loss and this increased to a mean over-prediction of 18.25 with ±5% weight loss
  • Owen had a group mean under-prediction error of 5.82% prior to weight loss and this changed to a group mean over-prediction error of 4.54%. Mifflin-St. Jeor had a group mean over-prediction error of 4.68% to an over-prediction error of 13.18% after ±5% weight loss.
  • Owen had a group mean under-prediction error of 5.82% prior to weight loss and this changed to a group mean over-prediction error of 4.54%
  • Mifflin-St. Jeor had a group mean over-prediction error of 4.68% to an over-prediction error of 13.18% after ±5% weight loss
  • WHO/FAO/UNU had a group mean over-estimation error of 10.83% prior to ±5% weight loss and this increased to a 17.81% group mean error after weight loss.
Author Conclusion:
  • The equation of Owen in normal weight, Bernstein in overweight and of Robertson and Reid in obese subjects should be chosen when we have to predict REE in young women. Due to metabolic adaptations occurring during therapeutic or spontaneous energy restriction, we suggest using Owen’s equation.
  • We evaluated the precision of the predictive equations over the entire population. Our results indicate that in the age group ranging 18 to 35 years, the most accurate equations were Bernstein’s and OUR, followed by Owen’s and Mifflin’s, which presented slight under-estimation and over-estimation errors respectively
  • From a clinical perspective, the REE prediction after the loss of 5% of the initial weight was inappropriate so that all equations, including OUR, had to be considered inaccurate
  • In the context of a clinical evaluation and therapeutic approach, it is important to evaluate the intensity and duration of the nutritional restriction because use of prediction equations could yield considerable RMR over-estimations
  • From a physiological point of view, the error analysis indicated that energy restriction influenced RMR with consequent increase of the metabolic efficiency.
Funding Source:
University/Hospital: University Federico II (Naples Italy)
Reviewer Comments:

Strengths 

  • Objective comparison of several equations was performed in the consideration of different weight status
  • Sophisticated, appropriate statistics
  • Careful evaluation of each equation being compared
  • IC protocol was clearly presented. Intervening factors, such as smoking, physical activity, tea and coffee consumption were monitored.
  • Conclusions were supported by the results.

Generalizability/Weaknesses

  • Questionable validity of indirect calorimeter
  • Menstrual cycle was not controlled in the study design
  • The resulting equation (OUR) was able to apply to young female population (age 18 to 35) with different body weight (normal, overweight or obese).

[Evidence Analyst note: Bias% was (REE measured minus REE predicted) x 100 /REE predicted, which is a different proportion than IC study.]

Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) Yes
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
 
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
3. Were study groups comparable? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? Yes
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) Yes
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? No
  4.1. Were follow-up methods described and the same for all groups? N/A
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) ???
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? ???
  4.4. Were reasons for withdrawals similar across groups? N/A
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? No
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) N/A
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? Yes
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? Yes
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? ???
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? ???
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? Yes
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? Yes
  8.6. Was clinical significance as well as statistical significance reported? Yes
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes