Healthy Non-Obese Adults (2010-2012)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
  1. Derive predictive equations of basal metabolic rate (BMR) for adult Malaysians
  2. Compare with the current FAO/WHO/UNU (1985) and Henry and Rees (1991) predictive equations.

Definitions

  • WHO/FAO formula: Used weight only formula.
Inclusion Criteria:
  1. Adults.
  2. Healthy showing no signs or symptoms of disease
  3. Acceptable range of BMI 20.5-25.0 kg/m2 for males and 18.7-23.8 kg/m2 for females
  4. From ethnic groups—Malay, Chinese, Indian and Dayak.
Exclusion Criteria:
  1. Nonhealthy
  2. Obese.
Description of Study Protocol:

Same for all Participants

BMR measured IC using the Douglas bag technique.

  • Subjects introduced to machine and protocol the evening before to minimize anxiety
  • Advised to abstain from coffee, cigarettes, heavy meals, alcohol and strenuous exercise the evening prior to measurement
  • IC after 12 hr overnight fast and “undue exertion” on the way to the research center
  • Rested 30 minutes before IC measurements
  • Females measured within the first 10 days of menstrual cycle
  • Measurements collected between 6 am and 8:30 am in a neutral thermal environment
  • Triplicate samples of expired air (10 min. each) from each subjects
  • Calibrated frequently using oxygen free nitrogen
  • BMR values considered valid when intra-subject coefficient of variation was 2.5% or less.

Anthropometrics following IC—Height and weight using standard procedures.

Data Collection Summary:
  • Body mass index (BMI) was calculated as: Wt/Ht2

Measured BMR of each subject was compared to the following predictive equations:

  1. FAO/WHO/UNU (1985): Use
  2. Henry & Rees (1991)
  3. Schofield et al (1985)

Blinding: Not used.

Description of Actual Data Sample:
  • One urban and one rural area sampling to make it as representative as possible of the local population.
  • Total of 5623 adults aged 18-60 y from 6 regions were screened.
  • A sub-sample of 656 healthy subjects (307 males and 349 females) was selected for this study.
  • The adults were categorized into 2 age groups (18-30 and 30-60) per gender for analysis.

Summary of Results:

Statistics

  • Correlation and regression analysis was used to determine relationship between variables.
  • Significance was set at P=0.05.

Major Results

  • Regression analysis indicated that only weight contributed significantly to the dependent variable (BMR) for both male and female subjects (P<0.05).
  • Age-specific predictive equations generated by this study for Malaysian males and females when compared to FAO/WHO/UNU and Henry and Rees showed a significantly lower BMR (P<0.01) compared to the BMR predicted by FAO/WHO/UNU and Henry & Rees for both male and female subjects.
  • Linear regression of BMR on body weight derived from this study were compared with the predicted formulas by FAO/WHO/UNU and Henry and Rees for the different age groups. The differences were between 4% and 12% for male subjects and 2% and 9% for female subjects.
  • The coefficient of determination (r2) (range 0.25-0.42) were close to those obtained by Schofield et al (r2 between 0.36 and 0.44) and to those of Henry & Rees (r2 between 0.35 and 0.42) for the 18-60 year age span.
  • Studies by Schofield showed 8-10% lower BMR in the tropics.
  • There were no significant differences in BMR between the major ethnic groups in the present study.
  • It is possible that differences in body composition and the relationship between BMR and independent variables (age, sex, and body size) may vary among populations including seasonal variations of BMR corresponding with diet and/or temperature changes.
Author Conclusion:
  • The present study shows that the BMR in adult Malaysian is lower than that predicted by the FAO/WHO/UNU and Henry and Rees equations and should not be dismissed. There is good reason to believe that the capacity to slow down metabolism in a hot and humid climate experienced throughout the year is a genuine phenomenon in Malaysia to be considered besides body size and composition.
  • These findings suggest that at equal energy intake recommendation for similar body weight, the lower energy needs of Malayasian would put them at greater risk of obesity. It is recommended that the predictive equations derived from this study be taken into account in formulating energy requirements of the adult population in Malaysia.
Funding Source:
Government: Ministry of Science Technology and the Environment
Reviewer Comments:

Strengths

  • Large sample size
  • Subjects selected from both urban and rural areas as well as 4 ethnic groups so more representative of general population
  • Introduction to study protocol and IC to minimize anxiety.

Limitations

  • Limited generalizability; sample consisted of Malaysian adults
  • Cross-sectional in design; does not allow for cause and effect
  • Subjects did not spend the night at the research center; some research indicate doing IC measurements with subject in same room where slept affects RMR (Arciero et al, 1993).
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? Yes
  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