Healthy Non-Obese Adults (2010-2012)

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

Objectives of study

  1. To generate 2 regression RMR equations from healthy Chinese subjects
  2. Three existing equations (WHO, Liu and Jia) equations and the 2 equations to be cross-validated in healthy and patients with chronic diseases.


  • WHO/FAO formula: Used weight and height formula.
Inclusion Criteria:

Healthy Subjects

  1. Healthy
  2. Adults
  3. Chinese
  4. Volunteers among staff working in Shatin Hospital.

Chronic Disease Subjects

  1. Adults
  2. Chinese
  3. Not on oxygen therapy
  4. Have diagnosis of heart disease, stroke and chronic obstructive airway disease (COAD)
  5. Patients from same hospital as staff.
Exclusion Criteria:

Healthy Subjects

  1. In poor health
  2. Not of Chinese ethnicity.

Chronic Disease Subjects:

  1. On oxygen therapy
  2. Not of Chinese ethnicity
  3. With diagnosis other than listed.
Description of Study Protocol:


  • Height, Weight, Fat-Free mass measured, Skinfold thickness measurement-biceps and triceps.

Resting energy expenditure

  • IC type: Delta trac with canopy system
  • Equipment of Calibration: Not specified
  • Coefficient of variation using std gases: No
  • Rest before measure (state length of time rested if available): Yes
  • Measurement length: Not specified
  • Steady state: No steady state mentioned.
  • Fasting length: Yes; 10 h
  • Exercise restrictions XX hr prior to test? Likely at least 10 h
  • Room temp: 26-30 degree C
  • No. of measures within the measurement period: 1
  • Were some measures eliminated? Not reported
  • Were a set of measurements averaged? Not reported
  • Coefficient of variation in subjects measures? Not reported
  • Training of measurer? Not reported
  • Subject training of measuring process? Not specified.
Data Collection Summary:

Was blinding used? No.

  1. Measured RMR with IC
  2. Body mass index (weight in kg/height in m2
  3. Percentage body fat measured using a body composition analyzer and skinfold thickness measurements
  4. Percentage body fat measured by skinfold thickness measurement was calculated by using the Durnin-Womersley equation (1974).
  5. Fat-free mass (FFM) was calculated by subtracting fat mass (body weight x percentage body fat) from body weight
  6. Predicted RMR equations for comparison of measured RMR: Liu, Jia and WHO equations.

Independent variables of height, weight, age, body fat by bio- impedance analysis (BIA), body fat by skinfold, FFM by BIA, and FFM by skinfold.

Description of Actual Data Sample:

Two groups were recruited:

  1. 134 (24 M, 110 F) healthy Chinese subjects aged 16-88 recruited from volunteers among staff working at hospital; convenience sample
  2. 30 patients (12 Male, 18 Female) aged 44-92 with chronic disease who were not on oxygen therapy recruited from same hospital.

Healthy subjects were divided into 2 groups: Group I (n=70) (14 M, 56 F; aged 16-79) was to generate 2 prediction equations for RMR using age, weight, percentage body fat and fat-free mass by bio-impedance analysis and Group II (n=64) (10 M, 54 G; aged 22-88) was used to test the equations together with the 3 other prediction equations.

Anthropometrics–Group I

  • Height (m): 1.57±7.7x10-2
  • Weight (kg): 58.3±10.0
  • BMI: 23.6±3.8.

Anthropometrics–Group II

  • Height: 1.55±7.4x10-2
  • Weight: 56.0±11.1
  • BMI: 23.1±4.1.


  • Height: 1.54±8.9x10-2
  • Weight: 48.2±12.3
  • BMI: 20.1±4.4.


  • Pearson coefficient was used to examine the relationship between different variables (age, weight, height, BMI, percentage body fat and fat-free mass) and measured RMR
  • Statistical significance set at P <0.05).
Summary of Results:

In healthy subjects, there was a negative correlation with age, and positive correlations with weight, height, BMI, percentage fat value calculated using skinfold measurement (all significant at P<0.05), and fat-free mass, the correlation being the highest with fat-free mass using BIA (r2 =0.78) or fat-free mass using skinfold (r2=0.73) (P<0.001) The correlations between the FFM measured by BIA or by skinfold and measured BMR was not statistically different in healthy subjects or patients.

With the exception of age, the same was observed in patients (but, percentage body fat by BIA; not statistically significant).

Correlation coefficients

In Healthy Subjects

  • Measured RMR x Age=-0.36
  • Measured RMR x Wt =0.71
  • Measured RMR x Ht =0.68
  • Measured RMR x BMI=0.41
  • Measured RMR x Percentage body fat by skinfold=0.56
  • Measured RMR x Fat-free mass by BIA=0.78
  • Measured RMR x Fat-free mass by skinfold=0.73.

In Patients

  • Measured RMR x Age=-0.21 (P=0.27)
  • Measured RMR x Wt=0.61
  • Measured RMR x Ht=0.54
  • Measured RMR x BMR=0.41
  • Measured RMR x Percentage body fat by skinfold=0.52
  • Measured RMR x Fat-free mass by BIA=0.61
  • Measured RMR x Fat-free mass by skinfold=0.61.

The 2 equations generated by regression analysis were:

  • 72.345 x FFM by BIA - 20.423 x Age(y)+3261.8; r2 =0.65
  • 57.562 x W - 26.795 x Z +3340.2.


Healthy subjects

  • The measured BMR was 5025 KJ ±967 SE/d (1201 kcal/d ±231 kcal)
  • BMR predicted by Liu equation (5138 kJ) was the closest to the mean of measured RMR (5025 kJ; 1201 kcal/d), the mean difference (113 kJ; 27 kcal/d) being the smallest compared with other equations (FAO/WHO/UNU (1985), Jia et al (1999).
  • The mean and mean difference of calculated BMR from WHO equation was 5481 kJ/d ±845 kJ SE (i.e., 1310 kcal±202 kcal/d SE)
  • The mean difference [range?] between predicted (WHO) and measured BMR with 2 SE was 300 kJ to ~600 kJ (71.7-143.4 kcal)
  • In healthy Chinese subjects, it was found that BMR expressed per kg fat-free mass determined by BIA and skinfold measurement were 120 and 114 kJ/kg FFM, respectively.
  • These were lower than values for BMR/kg FFM of Indians (129 kJ/kg FFM) and Australians (124 kJ/kg FFM).
  • However, they were comparable to Liu et (1995) (113 kJ/kg FFM).
  • The total body fat and FFM measured by skinfold was not statistically different from that obtained by BIA.
  • Predicted equations derived from healthy subjects underestimated the REE of subjects with disease.
Author Conclusion:
  • “It is difficult to derive one global prediction equation that is suitable for all populations in the world because of the biological, physical and environmental variations.”
  • “Our findings confirm that BMR of healthy Chinese subjects would be best predicted by the Liu equation, which may be used to estimate BMR (and indirectly TEE) when neither indirect calorimetry nor the doubly-labeled water technique is available.”
  • “Fat –free mass is the best predictor of measured RMR”
  • “BMR prediction equations derived from healthy populations may not be applicable to the patient population; which is of relevance in the clinical setting.”
Funding Source:
University/Hospital: The Chinese University of Hong Kong
Reviewer Comments:


  • Use of both skinfolds and BIA for FFM.


  • Methodology of IC poorly described
  • Small sample sizes (patients and when healthy individuals are grouped); limited power to predict BMR (?)
  • Limited generalizability with Chinese ethnicity
  • No discussion of physical activity or dietary measures; abstaining from physical activity prior to IC not mentioned
  • Patients had inpatient conditions prior to IC but healthy subjects it was not discussed whether they slept overnight in hospital or not; could affect RMR (resting period prior to IC not described)
  • Self-selection bias with volunteers from hospital; may not be representative of general community.
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? N/A
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? N/A
  1.3. Were the target population and setting specified? N/A
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? N/A
  2.2. Were criteria applied equally to all study groups? N/A
  2.3. Were health, demographics, and other characteristics of subjects described? N/A
  2.4. Were the subjects/patients a representative sample of the relevant population? N/A
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) 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? N/A
  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? 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%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? N/A
  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? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? N/A
  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? No
  7.1. Were primary and secondary endpoints described and relevant to the question? N/A
  7.2. Were nutrition measures appropriate to question and outcomes of concern? N/A
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? N/A
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? N/A
  7.5. Was the measurement of effect at an appropriate level of precision? N/A
  7.6. Were other factors accounted for (measured) that could affect outcomes? N/A
  7.7. Were the measurements conducted consistently across groups? N/A
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? N/A
  8.2. Were correct statistical tests used and assumptions of test not violated? N/A
  8.3. Were statistics reported with levels of significance and/or confidence intervals? N/A
  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)? N/A
  8.6. Was clinical significance as well as statistical significance reported? N/A
  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? N/A
  9.2. Are biases and study limitations identified and discussed? N/A
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? N/A
  10.2. Was the study free from apparent conflict of interest? N/A