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Citation:
Kitzman-Ulrich H, Hampson R, Wilson DK, Presnell K, Brown A, O'Boyle M. An adolescent weight-loss program integrating family variables reduces energy intake. J Am Diet Assoc. 2009 Mar; 109(3): 491-496.

PubMed ID: 19248868
Study Design:
Randomized Controlled Trial
Class:
A - Click here for explanation of classification scheme.
NEUTRAL: See Research Design and Implementation Criteria Checklist below.
Research Purpose:
  • To evaluate a family-based psycho-educational and behavioral skill-building weight loss program for adolescent girls that integrated Family Systems and Social Cognitive Theories
  • The primary hypothesis tested was that the multi-family therapy plus psycho-education group and the psycho-education-only group would demonstrate greater reductions in adolescent body mass index Z-score and energy intake as compared to the control group, with strongest effects in the multi-family therapy plus psycho-education group.
Inclusion Criteria:
  • Female adolescents aged 12 to 15 years
  • body mass index higher than the 95th percentile
  • Not participating in a weight-loss program
  • Ability to engage in physical activity
  • At least one adult family member willing to participate.
Exclusion Criteria:

None specifically mentioned.

Description of Study Protocol:

Recruitment

Participants and family members were recruited through pediatrician offices and promotional materials.

Design

Randomized controlled trial. Participants were randomized through letters containing group assignment.

Intervention

Randomized to one of three groups:

  • Multi-family therapy (45 minutes weekly) plus psycho-education (curriculum included weekly sessions with behavioral skill building and psychosocial components) group
  • Psycho-education only group
  • Wait-listed control group
  • None of the groups were given a specific caloric restriction
  • Adolescents were encouraged to self-monitor food group servings with a pictorial goal sheet to achieve a healthful diet within the recommended calorie range based on the Food Guide Pyramid.

Statistical Analysis

  • ANCOVA controlling for race was used to test for differences between groups for body mass index Z-score, energy intake and family variable change scores
  • Based on large effect size and alpha level of 0.05, 66 subjects were needed for adequate power (0.80) to detect differences between three groups and 42 subjects were needed to detect differences between two groups.
Data Collection Summary:

Timing of Measurements

The study was conducted in two cohorts between December 2002 and June 2003. body mass index, energy intake and family measures were assessed at baseline and after 16 weeks.

Dependent Variables

  • body mass index based on weight and height collected on a balance beam scale with stadiometer
  • Energy intake measured with 24-hour dietary recalls. The initial recall was collected in person and remaining recalls were collected on random days by telephone.
  • Family measures assessed with the Self-Report Family Inventory, a 36-item questionnaire.

Independent Variables

  • Multi-family therapy plus psycho-education group
  • Psycho-education only group
  • Wait-listed control group.

Control Variables

Race.

Description of Actual Data Sample:
  • Initial N: 66 eligible families. 44 volunteered for the study, and two withdrew prior to randomization, resulting in 42 families.
  • Attrition (final N): 42 adolescent females, 42 mothers and 26 fathers gave baseline data, and 35 families (83%) completed baseline and 16-week measures (three families dropped out at baseline and four families were lost to follow-up)
  • Age: Mean age 13.3 years for adolescents, 42.9 years for mothers, 45 years for fathers
  • Ethnicity: 55% white
  • Anthropometrics:
    • Psycho-education-only group had considerably higher SFI Nurturance scores compared to the control group at baseline
    • Non-completers were significantly older than completers 
  • Location: United States.
Summary of Results:

Key Findings

  • Average attendance was 42.6% for the multi-family therapy plus psycho-education group and 45.6% for the psycho-education-only group
  • Adolescents in the psycho-education-only group demonstrated a greater decrease in energy intake compared to the multi-family therapy plus psycho-education and control groups (P < 0.01)
  • Positive changes in family nurturance were associated with lower levels of adolescent energy intake (R=-0.60, P<0.05)
  • No significant effects were found for body mass index.

Mean (Standard Deviation) Change in Energy Intake and BMI Z-score from Baseline to Post-intervention by Group

Variables

Multifamily Therapy Plus Psycho-Education

Psycho-Education Only

Control

Baseline body mass index Z-score 2.2 (0.4), N=14  2.3 (0.3), N=13  2.3 (0.3), N=8 

Baseline energy intake 

1,512.6 (622.3), N=8 1,555.5 (493.8), N=9

1,095.1 (372.1), N=7

Post-intervention BMI Z-score  2.2 (0.4)  2.2 (0.3)  2.3 (0.3)
Post-intervention energy intake  1,574.0 (515.1) 1,190.4 (296.3)  1,422.5 (430.5)
Change in BMI Z-score 0.0 (0.1) -0.1 (0.1)  0.0 (0.1) 
Change in energy intake 61.44 (423.9), P<0.01  -365.1 (456.7), P<0.01 327.4 (402.0), P<0.01

Other Findings

  • There was a significant worsening of conflict in the multi-family therapy plus psycho-education group compared to the other groups (P<0.01)
  • Improvements in overall family variables were not demonstrated in this study.
Author Conclusion:

This study evaluated a psycho-educational weight-loss program for overweight female adolescents that integrated family variables and a multi-family therapy group as a novel approach to parental involvement. The findings from this study provide preliminary support for a family-based psycho-educational weight-loss program that integrated family variables to reduce energy intake in overweight (higher than 95th percentile) adolescent girls. Reductions in energy intake are an important component of the energy balance equation and weight loss. Another key finding was that family nurturance was associated with lower levels of energy intake and may be an important family variable to consider in future family-based weight-loss programs.

Reviewer Comments:
  • Small numbers of subjects in each group
  • Study was conducted in two cohorts between December 2002 and June 2003
  • Average attendance was below 50% for both the multi-family therapy plus psycho-education group and the psycho-education-only group
  • Differences at baseline between groups and between completers and non-completers
  • Authors note that although there were substantial reductions in energy intake, corresponding changes in body mass index were not seen.

Research Design and Implementation 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 nutrition or dietetics practice?
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?
???
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)
Yes
  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 used? (Concurrent preferred over historical controls.)
Yes
  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 or cross-sectional 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. Criterion may not be applicable in some cross-sectional studies.)
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?
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?
???
  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?
Yes
  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.)
Yes
  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?
Yes
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described?
Yes
  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?
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?
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?
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)?
N/A
  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?
Yes
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
 
 

Copyright American Dietetic Association (ADA).