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Healthy Non-Obese Adults (2010-2012)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

Compare the differences between measured REE with predicted REE calculated using the equations of Harris-Benedict, WHO/FAO and Liu.

Inclusion Criteria:
  • Understand and give written consent
  • Asian women aged 18 years or more
  • Raised in native country
  • Lived in US at least three months
  • Free of medications, diseases or trauma.
Exclusion Criteria:
  • Refusal to consent
  • Unable to meet inclusion criteria.
Description of Study Protocol:

Recruitment

Recruited from Washington State University; specific procedures not specified.

Design

Cross-sectional study.

Statistical Analysis

  • Means and standard deviations (SD) 
  • One-way analysis of variance to determine difference between measured REE of Chinese and Japanese
  • Paired T-test used to determine differences between measured REE and calculated REE from each equation
  • Pearson correlation used to determine relationships between measured REE and:
    •  Predicted REE by each equation
    • Height, weight, age, food intake and body mass index
  • Stepwise linear regression analyses using measured REE as the dependent variable and height, weight and age as independent variables.
Data Collection Summary:

Timing of Measurements

One measurement time.

Dependent Variables

  • Measured resting energy expenditure (REE):  [(VO2, L per minute), CO2 (L per minute; ml per minute; ml per kg per minute), RER, ventilation (L per minute)].
    • IC type: Open-circuit with mouthpiece and nose clip
    • Rest before measure: 30 minutes
    • Measurement length: Varied; completed when subjects reached steady state (Steady state” is when three or more 30-second VO2 values with CV of 10% or less AND VO2 values were no longer dropping)
    • Fasting length: 12-hour postprandial, 7 A.M. to 12 P.M.
    • Exercise condition: Refrain for 24 hours
    • Room temp: 21° to 22°C
    • Number of measures: One 30-second measure; not repeated
    • Coefficient of variation: 3.4%
    • Calibration:  Yes, by trained technician
    • Training of measurer: Experience technician with training
    • Training of subjects to IC process:  None reported.
  • Predicted REE
  • Harris Benedict (HB):  655 + (9.6 x kg) + (1.8 x cm) - (4.7 x age)
  • FAO: 
    • 30 to 60 years:  8.7 x kg + 829
    • 18 to 30 years: 14.7 x kg + 496
  • Liu: (13.88 x kg) + (4.16 x cm) - (3.43 x age) - 112.4.

Independent Variables

  • Weight: Measured to nearest 0.1kg (Lohman technique)
  • Height: Measured to 0.5cm (Lohman technique)
  • Body mass index (BMI): kg/m2
  • Age. 

Control Variables

  • Clinical:
    • Demographics: Completed demographic survey, including medical diagnosis
    • Monitored heart rate and took IC measurement when stable
    • Body temperature
  • Dietary: Completed three-day diet record (two weekdays and one weekend day), including vitamin per minute supplements and analyzed by nutritionist IV software.
Description of Actual Data Sample:
  • Initial N: Not given
  • Attrition (final N): N=36 females (N=35 eumenorrheic, N=1 post-menopausal)
  • Age: 27±6.0 years (range, 19 to 52)
  • Ethnicity: 16 Chinese; 15 Japanese; two Korean; one Indian; one Indonesian (Javanese) and one Thai
  • Other relevant demographics: Participants had been in the United States at least nine months.

Anthropometrics

  Mean±SD Range
Weight, kg 54.6±8.2 40.8 to 73.7
Height, cm 159.0±6.3  147 to 175
BMI 21.6±2.7 17.0 to 29.0

Location

California.

 

 

Summary of Results:

 

  • Correlations of independent variables (R) with measured REE (mREE):
    • Weight: 0.71 (P<0.001)
    • Height: 0.35 (P<0.05)
    • BMI: 0.64 (P<0.001)
    • Age: -0.07 (P>0.05)
  • Energy intake: Mean±SD = 1,654±378kcal; range = 1,163 to 2,506kcal per day. 
    There was no significant correlation between energy intake and measured REE (R=0.12, P>0.05).
  • Correlations of prediction equations with mREE:
    • Harris-Benedict: R=0.70; P<0.0001
    • FAO: R=0.67; P<0.0001
    • Liu: R=0.70; P<0.001
  • Stepwise regression analysis resulted in the following equation:
    • mREE (kcal per 24 hours) = 555.36 +12.60 X (kg weight) (R=0.71)
    • Height and age were not significant in this analysis, contrary to the Pearson correlation.  

Differences Between mREE and Calculated Estimates

  Group Mean Difference ±SE kcal per 24 hours
HB 110.6±15.5**
FAO 95.9±11.8*
Liu 90.6±10.5

* P<0.01

**P<0.001

Author Conclusion:

As stated by the author in body of report:

  • “In our study, the HB, FAO and Liu equation overestimated the measured REE of Asian women. The magnitude of the difference between predicted and measured REE was largest for the Harris Benedict equation, then FAO, and then Liu. FAO equation overestimated daily energy expenditure by 8.5% (P<0.001) and HB overestimated by 5.4% (P<0.01).”
  • “Previous and current findings suggest that a predictive equation specific to the racial group can predict energy expenditure more accurately than non-race-specific equations.”
  • “Conditions that vary in studies include ambient temperatures, input vs. output subject status, and degree of familiarity of subjects with the procedure.”
  • “One limitation of our study is that we did not determine the body composition of subjects to analyze REE relative to lean body mass or FFM . . .Cannot rule out the possibility that the discrepancy of measured REE from HB or FAO equation may be due to differences in the body composition of the sample populations. Correlations between measured REE and body weight and BMI were both significant (R=0.70 and 0.68, respectively) . . . which agrees with other studies and suggests the heavier the person, the higher the REE).
Funding Source:
University/Hospital: Margaret Nicholson Schafer Graduate Fellowship, Etta Losee Home Economica Scholarship
Reviewer Comments:

Strengths:

Selected an important ethnic group within a healthy population; also measured energy intake and correlated with measured REE.

 

Generalizability/Weaknesses: 

  • “There is limited generalizability to “present-day healthy Asian women” as some ethnic subgroups had an N=1 or N=2
  • “Weakness was the inability to determine the measurement length of REE (Was it only a 30-second measurement or were three 30-second measurements averaged?)”
  • “Study biases include self-selection sample"
  • “A behavioral confounder of smoking also not identified. Potential REE variability between eumenorrhia and post-menopausal and one person with obesity was not adjusted for in statistical analysis. (However, menstruation potentially controlled for statistically in analysis via age.)”
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? ???
  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? ???
  2.2. Were criteria applied equally to all study groups? N/A
  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? ???
3. Were study groups comparable? ???
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  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? ???
  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.) N/A
  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? ???
  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%.) No
  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.) Yes
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? No
  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? N/A
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  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? N/A
  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? Yes
  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? ???
  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)? N/A
  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