Pediatric Weight Management

Pediatrics and Physical Activity

Citation:

Maffeis C, Pinelli L, Schutz Y. Fat intake and adiposity in 8 to 11-y-old obese children. Int J Obes Relat Metab Disord 1996; 20: 170-174.

PubMed ID: 8646254
 
Study Design:
Cross-Sectional Study
Class:
D - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To investigate the relationship among adiposity, dietary intake, post-absorptive metabolic rate measurement and respiratory quotient (RQ) in a group of obese and non-obese children.

Inclusion Criteria:
  • Obese children with a body mass index (BMI) more than 97th percentile of reference values for age and gender
  • Non-obese children (control group) with a BMI less than 97th percentile of reference values for age and gender.
Exclusion Criteria:

Presence of hormonal or metabolic diseases in obese children.

Description of Study Protocol:

Recruitment

Not described.

Study Design

  • All children were measured for weight, height and skinfold thickness by same investigator
  • Before children were measured for post-absorptive metabolic rate, children consumed an unrestricted diet and did not perform any intense physical activity on the previous day
  • After the RMR measurement was collected using indirect calorimetry, a diet history was obtained from mothers and children using pictures of foods and various measuring cups
  • All diet history interviews were collected by the same dietitian.

Statistical Analysis

  • An unpaired T-test was used to compare obese and non-obese children
  • Pearson's moment linear correlation coefficient was used to quantify the degree of association between variables
  • Using RMR, ANCOVA was used to calculate energy consumption and macronutrient intake adjusted for RMR
  • Systat statistical package, version 5.0, SPSS Inc., Chicago, was used to analyze the data.
Data Collection Summary:

Dependent Variables

  • Post-absorptive metabolic rate: Measured using by respiratory gas exchange for 30 minutes using an open circuit computerized indirect calorimeter connected to a transparent hood system. The mean of the last 20 minutes was used to evaluate RMR. The energy expenditure was calculated using oxygen uptake (VO2) and carbon dioxide output (VCO2) using the formula of Lusk.
  • Anthropometric measurements: Weight, height and subcutaneous skinfold thickness measured. Body mass index (BMI) was calculated using height and weight. Deurenberg formula was used to calculate percent body fat and fat-free mass.
  • Energy intake: Usual weekly meal and snack intakes were obtained during an interview with mothers and children. Pictures of foods and various measuring instruments were used to help individuals with dietary recall. Meals, snacks, portion size and frequency were recorded on a standard questionnaire. Energy and macronutrient intake were calculated using a computerized database and analysis program.

Independent Variables

Measurements for respiratory quotient (RQ) to determine post-absorptive metabolic rate, anthropometric characteristics and dietary history recall.

Description of Actual Data Sample:
  • Initial N: 91 pre-pubertal healthy children (obese group: N=35; non-obese group: N=56)
  • Final N: 82; Data from five obese and four non-obese children were not included in the statistical analysis, because dietary intake was not available or hyperventilation-induced RQ were greater than 1.0.
  • Age range: 7.5 to 11.5 years
  • Ethnicity: White
  • Anthropometrics: Not described
  • Location: Verona, Italy.
Summary of Results:
  • Age was comparable in the two groups
  • Post-absorptive metabolic rate was significantly higher in obese than in non-obese children
  • Post-absorptive RQ was significantly lower in obese than in non-obese children (P<0.05).

Total Energy

  • Energy intake was comparable in obese and non-obese children
  • When energy intake was adjusted for resting metabolic rate, energy intake was significantly lower in obese than in non-obese children (P<0.001).

Protein and Carbohydrate Intake

Protein and carbohydrate intakes (expressed as percent of total energy and in absolute terms) were not signficantly different between the two groups.

Fat Intake

  • Dietary lipid intake (expressed as percent of total energy intake) was slightly, though not signficantly, higher in obese children than in the non-obese group (either unadjusted or adjusted for RMR by ANCOVA)
  • In the total group, percent fat mass and lipid intake percent were significantly correlated 
  • A negative correlation between respiratory quotient and fat mass was also found (P<0.01).

 

Author Conclusion:
  • The authors concluded that obese prepubertal children self-report higher relative fat intakes and conversely lower relative carbohydrate intakes than non-obese children
  • Relative fat intake and adiposity are positively and significantly related.
Funding Source:
University/Hospital: University of Verona (Italy), University of Lausanne (Switzerland)
Reviewer Comments:
  • Strengths: Measurements of RMR and RQ
  • Limitations: Cross-sectional design.
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) 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? 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? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  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%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? Yes
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? Yes
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? 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? No
  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? No
  6.6. Were extra or unplanned treatments described? No
  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? Yes
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? 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? No
  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? 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? No
  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)? No
  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? No
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? ???
  10.1. Were sources of funding and investigators' affiliations described? ???
  10.2. Was the study free from apparent conflict of interest? ???