PWM: Balanced Macronutrient: Children Ages 6-12 (2006)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
  1. To examine differences in percent overweight changes at 6, 60 and 120 months in obese parents and children from families who participated in randomized studies evaluating family based behavioral treatment.
  2. To compare children and adults when given similar diet, exercise and behavior change recommendations.
  3. To contrast the long term efficacy of family based interventions that target children and their parents at intervals ranging from 6 months to 10 years.
Inclusion Criteria:
  1. Obese parents and children who participated in 1 of 4 behavioral weight control programs;
  2. child 8-12 years old,
  3. child 20-100% over average weight for age, sex and height,
  4. one parent willing to attend treatment meetings,
  5. parent and child literate,
  6. no medical problem which would limit exercise,
  7. no current psychiatric disorder,
  8. obese parent and obese child for whom percent overweight change responses available for all data points.
Exclusion Criteria:
None specified
Description of Study Protocol:

Weekly treatment meetings conducted for 8 weeks followed by monthly meetings for 6-12 month period. Subjects weighed at each meeting; separate groups for parents and children; subjects instructed to self monitor weight and food intake daily.

All obese participants placed on diets: children provided 1200 calorie diet; adults in first study placed on 1200 or 1500 calorie diets based on initial body size, adults in subsequent studies places on 1200 calorie diet.

Traffic Light Diet used to promote increased intake of low fat, low sugar foods and reduce intake of high fat, high sugar foods.

Equal proportion of adults and children randomized to each condition.

Treatment variables differed in each study: variables that could influence family based weight control that were studied included who should be the target of weight control treatment, diet alone versus diet plus exercise, parent weight, comparison of aerobic lifestyle or calisthenics exercise programs.

Data Collection Summary:

Dependent

  • Height (height board, measured physician/nurse reports, or self report);
  • weight (balance beam scale, measured physician/nurse reports, or self report);
  • percent overweight (relating measured BMI to 50th BMI percentile based on age and sex; all adults compared to 50th percentile for sex in 25-29 year old range)

Note: self report data were adjusted using constructed equation; percent of self report data used was as follows: 6 months, <1%; 60 months, 31%; 120 months, 19%.

Independent

Generation (parent or child)

Control Variables

  • sex
  • study

Statistical Analysis

ANOVA and ANCOVA to assess differences in parent and child relative weight over time; chi square analyses to compare percent of children or adults who showed at least a loss in percent overweight of –20 or gain of +20 at each time point; logistic regression to examine influence of sex, generation, initial percent overweight on differential changes in large percent overweight changes.

Description of Actual Data Sample:

Original Sample: not specified

Withdrawals/Drop-Outs: not specified

Final Sample: 113 families

Location: not specified

Race/Ethnicity: not specified

SES: not specified

Summary of Results:

Baseline analysis showed no differences in distribution of child or adult subjects by sex, but significant differences observed for baseline percent overweight , with children heavier than parents.

Significant effects of generation at 6, 60, and 120 months. No main effects of sex or interactions of sex with generation or study with generation observed.

Significant differences in rate of change between groups at 6 and 120 months.

Both children and parents show treatment effect from entry to 6 months and decrement in response to treatment from 6 months through 5 years. At 5 years children stabilize their relative weight change, while parents continue to increase percent overweight from 5 to 10 years.

Significant differences in percentage of children versus adults who had decrease of at least 20% overweight at 6, 60 and 120 months. Children show relatively stable percentage of large changes in percent overweight, parents show decline in large changes as follow up extended.

Generation shown to be significant predictor at each time point. Sex made no independent contribution, initial percent overweight was independent predictor of change at 6, 60, and 120 months.

Author Conclusion:

Most important finding is that obese children show better weight loss and weight maintenance than their obese parents. Differences begin at 6 months after treatment, and persist over 120 months. General decay in treatment effects over time for both parents and children, general pattern of greater maintenance for children.

Percent of children who maintain a large treatment effect (decrease in percent overweight of at least 20%) over time is greater at each time point than percent of adults. At 120 months over 20% of children maintain a large treatment effect compared to less than 1% of adults.

(No consistent pattern for large increases in percent overweight)

Differences in child and adult weight loss and maintenance may be due to behavioral or biological factors that favor child weight control, including influence of spouse support, behavior change advantage, shorter duration of bad habits in children, type of behavior change required for long term weight control (dietary change vs exercise), fewer fat cells in children, etc.

In the present sample there may have been some differences in the degree of child and parent obesity that influenced outcome (more obese may have more of an advantage in losing and maintaining greater weight loss). However, controlling for initial obesity did not influence the role of generation in ANOVA or regression models.

May be differences in motivation for children and adults who enter family based treatment, family’s reason for entering program may affect treatment results.

Paper provides first systematic evidence that it may be easier for children to lose and maintain weight than adults.

Funding Source:
Government: NICHD
University/Hospital: Universtiy of Pittsburgh School of Medicine
Reviewer Comments:

Weaknesses:

  • no demographic information given,
  • 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? ???
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? ???
  1.3. Were the target population and setting specified? ???
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? ???
  2.2. Were criteria applied equally to all study groups? ???
  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? No
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) ???
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? ???
  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? ???
  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.) ???
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? ???
4. Was method of handling withdrawals described? No
  4.1. Were follow-up methods described and the same for all groups? ???
  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%.) ???
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? ???
  4.4. Were reasons for withdrawals similar across groups? ???
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? ???
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? ???
  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.) ???
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? ???
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? ???
  5.5. In diagnostic study, were test results blinded to patient history and other test results? ???
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? ???
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? ???
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? ???
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? ???
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? ???
  6.6. Were extra or unplanned treatments described? ???
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? ???
  6.8. In diagnostic study, were details of test administration and replication sufficient? ???
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? ???
  7.2. Were nutrition measures appropriate to question and outcomes of concern? ???
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? ???
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? ???
  7.5. Was the measurement of effect at an appropriate level of precision? ???
  7.6. Were other factors accounted for (measured) that could affect outcomes? ???
  7.7. Were the measurements conducted consistently across groups? ???
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? ???
  8.2. Were correct statistical tests used and assumptions of test not violated? ???
  8.3. Were statistics reported with levels of significance and/or confidence intervals? ???
  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)? ???
  8.6. Was clinical significance as well as statistical significance reported? ???
  8.7. If negative findings, was a power calculation reported to address type 2 error? ???
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? ???
  9.2. Are biases and study limitations identified and discussed? ???
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? ???
  10.2. Was the study free from apparent conflict of interest? ???