Pediatric Weight Management

PWM: Prescribed Diet Plan and Nutrition Education (2006)

Citation:

Sothern, M., Loftin, M., Udall, J., Suskind R., Ewing, T., Tang, S., & Blecker, U. Safety, feasibility and efficacy of a resistance training program in preadolescent obese children. American Journal of the Medical Sciences, 2000; 319: 370-375. 

PubMed ID: 10875292
 
Study Design:
Non-Randomized Controlled Trial
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
Negative NEGATIVE: See Quality Criteria Checklist below.
Research Purpose:
  1. To examine the safety, feasibility, and level of compliance of a resistance training program in a group of preadolescent children.
  2. To examine the efficacy of the overall outpatient clinic based program, which included resistance training, with respect to its impact on BMI and body composition.
Inclusion Criteria:

Preadolescent obese children 7-12 years of age involved in on going clinical outcome trial for observing weight loss and maintenance in obese youth at Children’s Hospital of New Orleans.

Exclusion Criteria:

Weight less than 120% IBW (using NCHS percentiles), evidence of cardiovascular disease, diabetes, or other chronic systemic diseases.

Description of Study Protocol:

19 children enrolled in 1 year, 4 phase weight management program; subjects blocked for analysis from 6 cohorts with baseline age of <12 years. Control subjects with baseline age <12 years selected from 12 cohorts of similar program also based at Children’s Hospital. Subjects in control group received intervention approx. 1.5 years before subjects in treatment group.

IBW calculated by measuring weight and height, weight percentile matching height percentile determined according to NCHS percentiles; actual weight expressed as percentage of IBW. Subjects classified as mildly obese (120-149% IBW, Phase III), moderately obese (150-199% IBW, Phase II), or severely obese (>=200% IBW, Phase I).

Treatment and control subjects participated in multidisciplinary program with intensive 10 week period that focused on acute weight loss. Color coded handbooks used to explain all aspects of weight loss program. Subjects set short term weight loss goals to reduce level of obesity; weight maintenance program was prescribed once subjects achieved goal weight of <120% IBW.

During acute weight loss period, all subjects attended weekly 2 hour weight reduction clinic; instructed concerning protein-sparing modified fast (PSMF) diet, nutrition, and moderate intensity progressive exercise program (MPEP); walking program (control group) and behavior modification. Dietary adherence monitored through self-reported urine ketone records.

Treatment subjects given home based exercise program that included video; subjects and family members participated in 30-45 minutes moderate intensity (45-55% VO2 max) exercise during weekly intervention meetings. MPEP included aerobic, muscular flexibility, and strength (resistance) exercises.

Resistance training program consisted of balanced routine of 6-12 exercises designed for obese youth. Severely obese children initially performed 6 exercises per session, 2-3 additional added to each phase as subjects progressed. Subjects began exercises as instructed on video without weight or resistance for 4 weeks, clinical exercise physiologist then instructed subjects on proper technique at weekly session, subjects instructed to perform exercise routine 2 times per week with 1 day of rest in between; parents used as spotters. Subjects progressively increased amount of weight lifted from 0 lbs in week 1 to 3 lbs in week 10 for overhead press, bicep curl, triceps extension; 5 lbs for chest press, modified leg extension, modified leg curl. subjects recorded number of repetitions, amount of weight lifted, whether completed exercise video (60 minute exercise routine). Specific recommendations given for technique, movement time, duration, frequency, muscle group in use, and common errors.

Control subjects instructed to walk three times per week for 60 minutes at an intensity of 65-70% VO2 max. Target heart rate values based on age predicted formula.

Statistical Analysis

Two way repeated measured ANOVA to analyze longitudinal data; post hoc contrasts performed using Duncan’s multiple range test to determine efficacy of weight reduction and weight maintenance.

Data Collection Summary:

Dependent

  • weight (electronically calibrated scale),
  • height (stadiometer),
  • BMI,
  • triceps and subscapular skinfold thicknesses (Harpenden calipers – three measurements recorded and mean value used),
  • relative body fat (percentage of body weight) and lean body mass (LBM) determined according to formula by Slaughter et al (included regression formulas for age, sex, race).

Compliance measured by subject and parent self report records.

Control subjects did not have body composition analysis.

Independent

  • exercise program (MPEP) including resistance training (treatment) or walking program (control).

Control Variables

  • age,
  • sex,
  • race
Description of Actual Data Sample:

Original Sample: 19 treatment subjects (7M, 12F), 48 control subjects.

Withdrawals/Drop-Outs: Treatment group – 2 dropouts reached individual goal weight, 1 dropout was relocated, 1 dropout noncompliant and lacked family support.

Control group – data for dropout reasons not available.

Final Sample: 15 of 19 treatment subjects completed 1 year program (78.9%); 17 of 48 controls completed program (35.4%).

Location: New Orleans, LA

Race/Ethnicity: not specified.

SES: not specified.

Summary of Results:

Authors report that the decrease in total body weight over 1 year period in both groups was significant.

  • In treatment subjects, baseline weight significantly higher than weight at 10 weeks and at 1 year.
  • In control subjects, baseline weight higher than weight at 10 weeks but not significantly different from weight at 1 year.

However, while the text refers to the 1-year results in Table 2 in the article, Table 2 only provides 10-week outcomes. So, 1-year measures are not available. Selected outcomes at 10-weeks presented below.

Weight:

Significant weight loss was noted in all subjects

Group Baseline kg 10 Weeks kg Significance
Treatment 65.3±21.0 56.7±18.2 p<0.0003
Control 61.95±20.3 54.3±19.9 p<0.0001

For control subjects, the authors state that "the baseline weight was significantly higher than that at 10 weeks (p<.0001) but not significantly different than the weight at 1 year." This statement seems to indicate that control subjects' weight at 1 year was not significantly different than their weight at baseline. However, the authors also state, "The decrease in total body weight over the 1 year period in both groups was significant (p<.0003)." It appears that the second statement applies to the combined measures of both treatment and controls. However, without the 1 year results (missing from Table 2 in the text), it is unclear.

Although the authors do not state this, we would guess (based on the group means and variance) that the difference between groups in terms of weight loss was not significant--at least at 10 weeks.

% Ideal Body Weight (IBW):

% IBW significantly decreased in all subjects.

Group Baseline % 10 Weeks % Significance
Treatment 158.5±22.1 134.0±18.3 p<0.0001
Control 179.2±24.5 154.6±24.5 p<0.0001

Decrease in %IBW over 1 year was significant for both groups. In both groups, baseline %IBW was significantly higher than at 10 weeks and 1 year; difference between 10 weeks and 1 year was not significant.

It was unclear from the text whether the differences between treatment and controls were significantly different at either 10 weeks or 1 year.

BMI:

BMI decreased significantly in all groups at 10 weeks.

Group Baseline 10 Weeks Significance
Treatment 28.6±6.3 24.4±6.2 p<0.0001
Control 30.8±5.8 26.6±5.8 p<0.0001

Because increase in height over 1 year were statistically significant in both groups, long term efficacy was not apparent.

Decrease in BMI over 1 year was significant for both groups. In both groups, baseline BMI was significantly higher than BMI at 10 weeks and at 1 year. However, the difference (within groups) between 10 weeks and 1 year was not significant.

Whether treatment and controls were significantly different from each other at the 10 week or 1 year measurement is unclear.

Other Outcomes

In treatment subjects, decrease in body fat over 1 year period was significant (42.6 ±7.2% at baseline to 32.6 ±7.0% at 10 weeks to 31.0 +/- 8.5% at 1 year); 10 week measure not significantly different from 1 year follow up measure.

Fat free body mass did not change significantly in treatment group.

Compliance: treatment subjects reported mean compliance of 100% during first 10 weeks, attendance then decreased 33% to 67% during weeks 11-52. Activity records not required in control group.

Among control subjects, 25% retention rate for severely obese subjects, 33.3% retention rate for mildly obese, 40.7% retention rate for moderately obese subjects.

Author Conclusion:

Preliminary results indicate that application of regular resistance training in program to prevent and treat pediatric obesity in preadolescent children is not only feasible but also safe.

Study limitation is that subjects were not randomly selected.

Study also limited by the fact that interventions were not conducted simultaneously (1.5 year gap).

Control group not required to record activity, may have affected retention rate.

Resistance training may be safely used in an outpatient clinic based pediatric health promotion program for obese preadolescent children in conjunction with moderate intensity aerobic and flexibility exercises.

Whether resistance training promotes more effective method for weight loss and maintenance is in need of further investigation
Funding Source:
University/Hospital: Louisiana State University School of Medicine, Alfred I. duPont Hospital for Children, University of New Orleans
Reviewer Comments:

The purpose of this study was to determine whether adding a resistence training component to an existing childhood weight loss program was both safe and feasible. Because between group results were not well described, this severely limited the utility of the study.

Weaknesses:

  • 1-year measurements were not presented in the table (to which the text referred). Thus, while 1-year outcomes were reported as significantly different from baseline measurements for several variables, it was unclear how great the magnitude of this change was.
  • The text was often confusing, and it was unclear whether there were any significant differences between control and treatment groups in terms of weight loss.
  • Not randomized.
  • Groups not concurrent.
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? No
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? No
  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? No
  2.2. Were criteria applied equally to all study groups? No
  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? No
3. Were study groups comparable? No
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) No
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? No
  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? No
  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%.) No
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? No
  4.4. Were reasons for withdrawals similar across groups? No
  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? No
  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? 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? No
  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? No
  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? 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? 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? No
  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)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? No
  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? No
  10.2. Was the study free from apparent conflict of interest? Yes