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NC: Behavior Change Strategies (2007-2008)

Citation:

DeLucia JL, Kalodner CR. An individualized cognitive intervention: Does it increase the efficacy of behavioral interventions for obesity? Addict Behav. 1990; 15 (5): 473-479.

PubMed ID: 2248121
 
Study Design:
Randomized controlled trial
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

The purpose of the study was to assess the efficacy of the addition of a cognitive intervention to a behavioral weight loss program. 

Inclusion Criteria:
  • 15% over ideal weight as compared to the Metropolitan Height Weight Table (1983)
  • Adult men and women.
Exclusion Criteria:
  • Children
  • Less than 15% over ideal weight as compared to the Metropolitan Height Weight Table (1983). 
Description of Study Protocol:

Recruitment

Men and women were recruited through announcements in a university newsletter.

Design

  • Participants were blocked on sex and initial weight and randomly assigned to either a behavioral intervention alone (BI) or both a behavioral intervention and a cognitive intervention (BI plus CI)
  • Each group met weekly, 75-minute sessions for 10 weeks.

Blinding Used

No blinding.

Intervention

  • The behavioral intervention followed the program outlined by Ferguson (1975) Learning to Eat: Behavior Modification for Weight Control. The focus of this program is on changing inappropriate eating patterns and habits, particularly those associated with external cues of hunger. Each week consisted of 55 minutes of BI and 20 minutes of general discussion. Weekly homework assignments included daily food diaries.
  • The BI plus CI intervention, included the hopelessness, motivation and physical attribution sub-scales of the Master Questionnaire as the basis of the program (MQ). Each participant received individualized printed feedback which included pre-treatment responses to MQ items and alternative ways of thinking for incorrectly answered items. Group discussion focused on participants' responses to MQ statements and the presentation of new information and adaptive self-statements. Each week consisted of 55 minutes of BI (Ferguson's program) and 20 minutes of CI. Weekly homework assignments included daily thought diaries.

Statistical Analysis

  • ANOVAs were computed on expectations, number of sessions attended and number of homework assignments completed
  • MANOVAs were used to test the effects of the cognitive intervention, with treatment condition (BI, BI plus CI) and time (pre-test, post-test, follow-up) as the independent variable 
  • Wilk's F statistic was used to determine significance at the multivariate level.

 

Data Collection Summary:

Timing of Measurements

  • Pre-test
  • Post-test (10 weeks)
  • Follow-up (three months).

Dependent Variables

  • Variable 1: Physiological measures included, weight, percentage of body fat and reduction quotient (number of pounds lost, number of pounds overweight x initial weight / ideal weight x 100)
  • Variable 2: Behavioral measures included:
    • Eating Styles Questionnaire: Used to assess degree of stimulus control and behavioral patterns. Categories included binger, lazybones, guzzler, sugar sweetie, nibbler, gourmet, monotonous muncher, fatty, feeder, emotional eater and daily drinker. The questionnaire presented a series of situations and the participants identified which statements described their attitudes about eating. 
    • Behavioral Techniques Usage Percentage: Determined based upon responses to an eating behavior questionnaire. Subjects rated the percentage of time each intervention strategy was used (0 to 100%). The mean behavioral technique usage percentage was calculated by summing the rating of percentage of time used for each technique and dividing by the total number of techniques.
    • Master Questionnaire: Stimulus control and energy balance scales used to assess behavioral effects of the weight loss interventions
  • Variable 3: Cognitive measures measured using the Master Questionnaire to assess hopelessness, motivation, physical attribution scales used to assess cognitive changes about weight loss and a self-report questionnaire used to assess negative thoughts about weight loss.

 Independent Variables

Cognitive therapy and time (pre-test, post-test and follow-up).

 

Description of Actual Data Sample:
  • Initial N: 63 (seven males, 56 females)
  • Attrition (final N): Not mentioned
  • Age: 43.62 years
  • Ethnicity: Not mentioned
  • Other Relevant Demographics: None
  • Anthropometrics: Average of 57.5 pounds overweight (mean 46.24% overweight);Average percentage body fat 36.76%
  • Location: Purdue University.

 

Summary of Results:

 

Variables

Pre-test

Mean (SD)

Post-test

Mean (SD)

Pre- to Post-test Comparison

Significance Follow-up Pre- to Follow-up Comparison Significance
Physiological Measures              
Weight

184.70 (41.03)

177.85 (37.31)

-4.30 0.001 176.30 (37.19) -5.76 0.001

Percentage of Body Fat

36.60 (4.6)

31.95 (4.12)

4.06

0.001

 

30.04 (4.28)

6.29

0.001

 

Reduction Quotient

N/A

16.92 (0.16) 3.66

0.001

21.14 (0.23) 

-0.84

0.001

Behavioral Measures              
MQ: Stimulus Control 5.04(2.27) 3.00 (2.17) -4.46  0.001 3.13 -5.06 0.001
Energy Balance 1.73 (1.45)

1.32 (1.39)

-0.83 0.410

1.17

-3.02 0.004
Behavioral Technique Usage 33.59 (19.17)

55.88 (30.54)

-9.15

0.001

73.97 (33.64)

15.90

0.001

Eating Styles Questionnaires:              
  • Binger

3.89 (1.01) 

1.89 (1.01) 

8.54

0.001

 1.49 (1.16)

8.44

0.001

  • Lazybones
2.99 (0.96) 0.94 (0.96) 5.72 0.001 0.51 (0.77) 4.38 0.001
  • Guzzler
3.34 (1.19) 1.43 (1.18) 6.13 0.001 1.02 (1.18) 5.51 0.001
  • Sugar Sweetie
3.80 (1.34)

1.81 (1.37)

7.12 0.001 1.49 (1.37) 7.07 0.001
  • Nibbler
4.11 (1.53) 2.11 (1.53) 8.38 0.001

1.68 (1.43)

8.23 0.001
  • Gourmet
3.43 (1.31)

1.43 (1.31)

6.47 0.001 0.93 (1.27)

5.51

0.001
  • Muncher
4.62 (1.74) 2.62 (1.74) 7.21 0.001

2.05 (1.54)

10.81 0.001
  • Fatty Feeder
2.81 (1.3) 1.83 (1.30) 8.56 0.001

1.43 (1.15)

8.62 0.001
  • Emotional Eater
4.74 (1.66) 2.74 (1.66) 9.49 0.001

1.13 (1.79)

9.38 0.001
  • Daily Drinker 
2.85 (1.15)

0.85 (1.15)

4.05 0.001

0.64 (0.95)

4.72

0.001

Cognitive Measures

 

 

 

       

Master Questionnaire:

  • Hopelessness
  • Motivation
  • Physical attribution

3.53

5.18 (3.15)

5.98 (2.59)

1.76 (1.83)

2.66 (2.72)

3.41 (2.88)

 -539

-5.85

-4.80

 0.001

0.001

0.001

 2.19 (1.81)

3.26 (3.04)

3.34 (3.20)

 -3.92

-3.62

-6.87

0.001

0.001

0.001

Negative Thoughts about Weight Loss

72.94 (24.96)

58.36 (24.6) -3.80 0.001 65.07 (25.54) -1.53 0.134

 Other Findings

  • There was no significant difference in treatment groups at pre-test on the dependent measures
  • ANOVAs were computed on expectations, number of sessions attended and number of homework assignments completed. Differences between treatment groups were not significant.
  • Both groups achieved significant improvements in physiological, cognitive and behavioral measures over time
  • Differences in physiological, cognitive and behavioral measures were not significantly different between treatment groups.

 

Author Conclusion:
  • Results of repeated measures MANOVAs did not support increased effectiveness of a cognitive intervention to facilitate weight loss 
  • Limitations of the study included:
    • Small weight loss and a short follow-up
    • The effects of cognitive therapy may not result in greater initial weight loss but may lead to greater weight loss over time. The amount of cognitive therapy used in this study was not sufficient to produce desired changes. 
    • More than seven hours are necessary to integrate the principles of cognitions and their effects on behavior 
    • The cognitive intervention group did show, NS, greater improvement in cognitive change than did the behavioral intervention group 
  • Treatment effects may have been blurred by individual differences and variability. In this study, variability in cognitive functioning was not taken into consideration.
  • The question concerning the effectiveness of cognitive interventions is complex. Future research examining the effectiveness of cognitive interventions in the area of weight loss, should include measures other than weight related ones. Longer follow-ups are necessary to assess long-term weight loss maintenance. Improved initial assessment of cognitions and behaviors followed by interventions based on these assessments may result in focused treatments that are more effective.
Funding Source:
University/Hospital: Purdue University, University of Akron
Reviewer Comments:
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? 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? ???
  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? ???
  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? ???
  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? ???
  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.) 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? 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? No
  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? N/A
  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? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? ???
  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? No
  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? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? ???
  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? ???
  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? No
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? No
  10.1. Were sources of funding and investigators' affiliations described? No
  10.2. Was the study free from apparent conflict of interest? ???