Pediatric Weight Management

Parent Training or Modeling to Reduce Childhood Overweight (2006)

Citation:

Miraglia del Giudice E, Santoro N, Marotta A, Nobili B, Di Toro, Perrone L. Inadequate leptin level negatively affects body fat loss during a weight reduction programme for childhood obesity. Acta Paediatr 2002; 91: 132-135.

PubMed ID: 11951997
 
Study Design:
Non-Randomized Controlled Trial
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To report on the effect of a weight reduction program in 3 different groups of obese children assembled on the basis of their baseline leptin levels adjusted for BMI, gender & pubertal development.

The authors tested the hypothesis that inappropriate leptin concentrations would result in a decrease in the effectiveness of a weight loss program.
Inclusion Criteria:

Unrelated, obese children & adolescents aged between 5-15 years.

Obesity defined as BMI > 97th % for sex & age according to reference value (Must, 1991).

Exclusion Criteria:
Not specified.
Description of Study Protocol:

Patients were submitted to a weight loss program (6 month hypocaloric diet), in which they consumed a nutritionally balanced (50% CHO, 30% fat & 20% protein) self-selected diet of common foods (60% of the recommended dietary energy allowance for age & sex). Habitual level of PA during the program was also assessed.

Statistical Analysis

Wilcoxon signed rank test.

Data Collection Summary:

Dependent

  • Changes in BMI (measured ht & wt), Triceps & Subscapular skinfolds standard deviation scores after 3 & 6 months of weight reduction program.

Independent

  • Three groups of obese children subdivided according to their baseline leptin levels (leptin concentration Z-score relatively high levels: > 2 (n=20), appropriate levels: >= -2 <= 2 (n=42) and relatively low levels: < -2 (n=20)), based on blood samples.

Control Variables

  • Serum leptin levels were adjusted for BMI using reference ranges stratified according to gender & pubertal development.
Description of Actual Data Sample:

Original Sample: not specified

Withdrawals/Drop-Outs: not specified

Final Sample: 82 (45 boys, 37 girls) unrelated, obese Italian children & adolescents.

Location: Naples, Italy

Race/Ethnicity: Italian children

SES: not specified

Age: mean age 10.9; rang 5-15 years.

Summary of Results:

Baseline

There was no statistical difference in mean age, age at onset of obesity, baseline BMI, or triceps & subscapular skinfolds between the groups. Furthermore, there was no difference in the level of habitual physical activity between the groups.

Weight loss

Mean BMI & skinfold thickness at the end of the therapy were sig. lower (P<0.01) than baseline values.

Differences between groups

Although BMI reduction was more evident in the subset of patients with adequate leptin levels, no statistically significant differences were detected among the three categories of patients.

Reduction in triceps & subscapular skinfolds was also more pronounced in the leptin normo-producing patients than the hyper- or hypo-producing patients. Differences in the average of these changes were statistically significant after both 3 & 6 months on the weight reduction program.

Author Conclusion:

The effectiveness of this program was decreased in patients with relative hyperleptinaemia or hypoleptinaemia compared to children with baseline leptin levels appropriate to BMI gender & pubertal development. The more likely scenario to explain the author’s findings is that the ability to lose body fat, at least in childhood, is strictly dependent on the relative weight of genetic & environmental factors determining obesity. Patients with relative hyper- or hypo-leptinaemia are less sensitive to environmental variations (e.g., a weight loss program) than subjects with appropriate leptin levels.

Finally, the data presented in this work suggest that the information gained from leptin assays could provide predictive insight into an individual’s ability to lose body fat. It may therefore have important implications for out approaches to the treatment & prevention of childhood obesity.
Funding Source:
University/Hospital: Second University of Naples (Italy)
Reviewer Comments:

Limitations

This study’s hypothesis is different from other studies and may be determined to not be included.

This study does not have controls in the sense that there are no subjects who did not participate in the weight loss intervention.

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? No
  2.4. Were the subjects/patients a representative sample of the relevant population? ???
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? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) No
  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? No
  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.) No
  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? Yes
  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? No
  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? 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? Yes
  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? 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? 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? 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)? ???
  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