Pediatric Weight Management

PWM: Prescribed Diet Plan and Nutrition Education (2006)

Citation:

Sothern, M., Udall, J. Suskind, R., Vargas, A., & Blecker, U. Weight loss and growth velocity in obese children after very low calorie diet, exercise and behavior modification. Acta Paediatrica, 2000; 89(9): 1036-43.

PubMed ID: 11071081
 
Study Design:
Non-Randomized Controlled Trial
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:
  1. To apply a structured diet and exercise program in combination with behavior modifications and lifestyle alterations to treat obesity in children.
  2. To assess weight loss and growth velocity during the three component program of very low calorie diet (VLCD) followed by less restrictive balanced hypocaloric diet (BHD), moderate intensity progressive exercise program (MPEP), and behavior modification.
Inclusion Criteria:
Children 7-17 years of age enrolled in a 1 year outpatient weight reduction program at the Dept. of Pediatrics, LSU Medical Center, General Clinic Research Center and Children’s Hospital of New Orleans over 18 months; recruited through primary care physician referral or self-referral.
Exclusion Criteria:
Weight less than 130% of IBW (using NCHS percentiles); evidence of cardiovascular disease, diabetes, or other chronic systemic disease.
Description of Study Protocol:

Enrolled subjects were entered into one of four cohorts. New cohort of 11-18 subjects started every 3 months.

Subjects classified as mildly obese (130-149% IBW), moderately obese (150-199% IBW), or severely obese (>=200% IBW). All subjects had skinfold thickness above 85%th percentile for age and race at entry; relative fat was in excess of 30%.

All subjects participating were billed $750. One year program began with intensive 10-20 week intervention focusing on acute weight loss; mildy obese subjects enrolled in acute phase for 10 weeks, moderately and severely obese for 20 weeks. Color-coded handbooks used to explain aspects of weight loss phases of program, used as positive reinforcement. After acute intervention phase, subjects switched to weight maintenance diet for remainder of year or until goal weight (120% IBW) achieved.

All subjects attended weekly 2 hour outpatient weight reduction clinic, where they were instructed concerning VLCD, MPEP, behavior modification.

VLCD diet consisted of 1.5-2.0g protein/kg IBW/day and supplied approx. 800 kcal/day. Protein provided by lean meat, fish, chicken and accounted for <50% total calories. Carbohydrate intake limited to 20-25g/day to induce ketosis. Two cups vegetables (except high starch) allowed/day; fat from lean protein sources <40g lipid/day. All participants received supplemental calcium carbonate (2 500mg tablets taken twice/day provided 800mg elemental Ca); also supplemented with potassium chloride and daily multiple vitamin/mineral supplement. Subjects encouraged to drink at least 2 l of water or sugar free beverage daily.

Subjects taught to check urine for ketones each morning; records presented by subjects with weight loss information at weekly meetings to reinforce perception of success and assist therapists in assessing adherence.

Subjects participated in MPEP during clinic visits and at home; included moderate intensity aerobic exercises, strength and flexibility exercises. Subjects instructed to determine heart rates to ensure adherence to intensity of 45-55% VO2 max. Exercise program specific to class of obesity (mildly obese subjects allowed to exercise more). Activity performed at home was selected from program handbook or videocassette. Exercise record cards listing frequency, duration, type of exercise kept by each subject and checked at weekly clinic meetings.

Family behavior modification was integral component of acute program, with at least one parent’s attendance and involvement required during all aspects of weekly sessions. Behavior specialist met with parents and/or children together (both individual and group sessions). Incentives in form of rewards (stickers, certificates, sports equipment) given to subjects who reported ketones, dietary and exercise patterns consistently and for overall adherence.

Once subjects achieved lower obesity category, placed in long term gradual weight loss/weight maintenance program that replaced VLCD with 1200 kcal BHD for remainder of 1 year program or until 120% IBW achieved. BHD approx. 20% protein, 50-55% carbohydrate, maximum of 30% fat.

Subjects continued weekly weight reduction clinics, where instructed on diet, exercise, behavior modification. Weekly classes concluded with 3-45 min supervised exercise; intensity increased to 55-65% of VO2 max. Subjects instructed to continue home based exercise program; instruction on behavior modification given weekly.

Statistical Analysis

One way repeated measured ANOVA to analyze longitudinal data; post hoc contrasts performed using Duncan’s multiple range test to assess efficacy of weight reduction and maintenance; paired t-tests utilized to analyze observations collected at pre-VLCD and post-VLCD interventions.

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 )
  • lean body mass (LBM) determined with formula given by Slaughter et al.

Independent

  • Obesity classification (mild, moderate, severe).

Control Variables

  • Age
Description of Actual Data Sample:

Original Sample: 63 children (25M, 38F), 7-17 years.

Withdrawals/Drop-Outs: 7 subjects excluded for cardiac arrhythmia (n=1), diabetes mellitus (n=1), body weight <130% IBW (n=5).

Four subjects entering the program did not complete acute intervention phase - dropped out due to transportation conflicts (n=1) and poor motivation (n=3).

Seventeen of 52 subjects did not complete 1 year program. Sixteen patients did not complete program because they reached <120% IBW.

Final Sample: 56 entered program (25M, 31F). 52 of 56 subjects who entered the program (93%) completed acute intervention phase. 35 of 52 completed 1 year program (62.5%; 12M, 23F).

Location: New Orleans, LA

Race/Ethnicity: 75% of those entering program Caucasian, 25% African-American

SES: Middle to high SES, as all patients were self-pay and/or insured.

Summary of Results:

Outcomes by Weight Classification

Subjects in different weight categories remained in the acute phase of the program for different lengths of time. Mildly obese subjects (130-149%IBW) were kept on the very low calorie diet for 10 weeks, while moderately obese (150-199%IBW) and severly obese (>200%IBW) subjects were kept on the very low calorie diet for 20 weeks.

The following table presents the changes in BMI for the three weight classifications for subjects who completed the entire program (n=35) from baseline to post-vlcd and at 1-year.

Group Pre-VLCD BMI Post-VLCD BMI 1-Year BMI
Mildly Obese (n=11) 27.6±4.5 24.2±4.6 25.0±5.3*
Moderately Obese (n=18) 32.3±5.1 28.0±5.2 29.0±4.1*
Severly Obese (n=6) 43.1±4.7 37.7±4.7 34.8±5.6*
All Groups (n=35) 32.7±7.0 28.4±6.6 28.8±5.7*

*Significance of difference from baseline p<.0001, results in the above table are not adjusted for age or pubertal stage.

Severly and moderately obese subjects demonstrated a greater decrease in BMI than mildly obese subjects (significance of difference not reported).

Other Outcomes

Mean±SD

Measure Pre-VLCD Post-VLCD 1-Year
Weight kg* (n=35) 80.1±28.2 70.7±25.5 74.0±23.0*
% Ideal Body Weight* (n=35) 168.7±31.2 144.6±27.4 148.5±26.9*

*Significance of difference from baseline p<.0001, results in the above table are not adjusted for age or pubertal stage.

  • Post VLCD, significant average weight loss of 9.4 kg.
  • Average height increased significantly from 154.2 ±13.1 cm to 155.4 ±13.2 cm.
  • Mean %IBW decreased significantly from 176.2 ±33.9% to 150.6 ±30.4%.
  • Relative body fat (%) from skinfold thickness decreased significantly from 46.4% to 39.1%.
  • LBM did not change significantly.

Decrease in total body weight over 1 year was highly significant (80.1kg to 74.0kg). Increase in height over 1 year was statistically significant (154.2 cm to 158.4 cm average height).

10 of 12 boys showed height increments and growth velocities normal for respective ages; 18 of 23 girls had heights and growth velocities normal for respective ages.

Average %IBW decreased from 168.7% at pre-VLCD to 148.5 at 1 year follow up; decrease was highly significant. Difference between post-VLCD and 1 year follow up was not significant.

When data corrected for age, significant reduction in weight and BMI from baseline to 1 year disappeared.

Relative body fat as percentage of total weight calculated for 19 subjects; decrease in body fat over 1 year was highly significant (44.4% at pre-VLCD, 35.3% at 1 year). Post-VLCD not significantly different from 1 year measurement.

Slight increase in LBM from entry to post-VLCD and at 1 year, but increase was not significant.

Author Conclusion:

Multidisciplinary weight reduction program that combines VLCD, BHD, MPEP and behavior modification is effective means for weight reduction in obese children and adolescents.

Limitation to the study is that data are not corrected for age or pubertal stage.

Pre entry height velocity unknown, cannot accurately assess whether impairment in height velocity occurred during intervention. However, data suggest that most subjects are able to sustain growth at a normal rate for age or height age.

Limitation to the study is unavailability of accurate measures for body composition – only 19 subjects completed skinfold measures at all 3 time points.

Unclear effect of program fee on motivation; dropouts often did not pay total fee and fee may have created deterrent to follow up rather than enhancing attendance and completion.

No data on subjects who did not participate in 1 year evaluation (37.5% attrition rate).

35% dropout rate – cannot be concluded that use of VLCD in multi-disciplinary outpatient clinic is safe and effective in all patients and environments.

Results indicate that program should be carefully monitored because safety of VLCDs is still under investigation.

Funding Source:
Government: State of Louisiana grant
University/Hospital: Louisiana State University School of Medicine, Alfred I. duPont Hospital for Children, University of New Orleans
Reviewer Comments:

Limitation

  • no controls
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? No
  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.) 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? 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? 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