Pediatric Weight Management

Pediatrics and Physical Activity

Citation:

Ball EJ, O’Connor J, Abbott R, Steinbeck KS,Davies PSW, Wishart C, Gaskin KJ, & Baur LA. Total energy expenditure, body fatness, and physical activity in children aged 6-9 y. Am J Clin Nutr 2001;74:524-28.

PubMed ID: 11566652
 
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:

The purpose of this study was to:

  1. measure total energy expenditure (TEE) by doubly labeled water (DLW),
  2. determine the proportion of TEE related to PA,
  3. investigate the relations between measures of PA and body fatness, and
  4. investigate possible sex differences in these relations.
Inclusion Criteria:
None stated.
Exclusion Criteria:

Children with chronic illness other than asthma or with acute illness at the time of the study were not recruited. No children were taking medications that would affect the results.

Description of Study Protocol:
  • Anthropometric measurements were obtained on the subjects including height and weight. BMI was calculated from these numbers.
  • TEE was measured over a period of 10 days by using the DLW method.
  • Fat-free mass was calculated from the O dilution space, fat mass was then calculated as well as percentage of body fat.
  • Resting energy expenditure (REE) was calculated using the Schofield equations based on body weight, age and sex.
Data Collection Summary:

Independent Variable:  physical activity level (PAL=TEE/REE)

Dependent Variables

  • BMI
  • fat mass body
  • fat percent

Confounding variables:  sex, age

Statistical Analysis:

  • One-way analysis of variance was used to examine differences in physical characteristics, total energy expenditure, and PALs between boys and girls.
  • Pearson’s correlation coefficient was used to derive the level of association between variables.
  • Stepwise multiple regression analysis was used to examine the relations between sex, measures of energy expenditure, and body composition.
Description of Actual Data Sample:

N: 106 (52 boys and 54 girls)

Age: 6.0-9.6 years old

Race/Ethnicity: Not stated

Anthropometrics: In terms of growth and body fatness, this sample was representative of the Australian pediatric population.

Location: Australia

Summary of Results:

There was no significant difference in PA level between boys (1.69±0.22) and girls (1.71±0.23).

In boys but not girls, PAL was inversely correlated with BMI (r = -0.37, P<0.01), fat mass (r = -0.46, P<0.005), and percentage of body fat (r = -0.50, P<0.0001).
Author Conclusion:
In boys but not girls, percentage of body fat is inversely associated with PAL. PA is one factor contributing to body fatness in boys, but additional factors may influence the size of the fat stores in girls. These results suggest that lower PALs may contribute to the rise in prevalence of childhood obesity, particularly in boys.
Funding Source:
University/Hospital: James Fairfax Institute of Paediatric Nutritions, Children's Hospital, University of Sydney, Queensland University, Royal Prince Alfred Hospital
Reviewer Comments:

Weakness: 

  • Not able to investigate sex differences found in the relation between physical activity and body fatness.
  • Design couldn’t address counfounders.

Strength:  Used doubly labeled water for TEE measurement.

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) N/A
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? N/A
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? N/A
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) N/A
 
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? 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? 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? N/A
  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? Yes
  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? Yes
  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? N/A
  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? 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? 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? No
  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? 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