MNT: Disorders of Lipid Metabolism (2015)

Imai S, Kozai H, Naruse Y, Watanabe K, Fukui M, Hasegawa G, Obayashi H, Nakamura N, Naito Y, Yoshikawa T, Kajiyama S. Randomized controlled trial of two forms of self-management group education in Japanese people with impaired glucose tolerance. J Clin Biochem Nutr. 2008; 43: 82-87. PubMed ID: 18818757
Study Design:
Randomized Controlled Trial
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Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
To determine the effectiveness of an educational program incorporating blood glucose self-monitoring on glycemic control in individuals living in Japan with impaired glucose tolerance.
Inclusion Criteria:
  • Impaired glucose tolerance (HbA1C levels 5.5% or more to less than 6.1%)
  • From 40 to 70 years of age
  • No prior history of systematic diabetes education
  • Provided written informed consent.
Exclusion Criteria:
  • Known mental disabilities
  • Assumed criteria outside HbA1C, age and education inclusion criteria.
Description of Study Protocol:


  • Initial recruitment from individuals who had an annual health check within three years at the Public Health Center of Habikino City, Osaka Prefecture, Japan
  • Cards sent to each individual and newspaper advertisement posted for recruitment of these individuals
  • Participants randomly assigned to either a support group (Rx group) or control group after stratification by gender, age and weight.


Randomized control trial.

Blinding Used

None. Education staff members were aware of group assignment. It was not clear if participants were aware of assignment.


  • Eight sequential diabetes education sessions regularly scheduled over six months lasting three hours per session. Most sessions covered topics on diet with support provided by the same dietitian or nurse.
  • Lectures were presented by either a physician specializing in diabetes, a dentist or dental hygienist, registered dietitians (RD) or physical fitness trainers
  • Group support education, group dynamics and individual consultations were emphasized
  • The RD-covered topics of portion control, eating order (vegetables first, carbohydrates last) and glycemic index
  • Energy goals were calculated for each patient (IBW X 30kcal for non-obese, 25kcal for obese)
  • Two cooking classes were taught emphasizing diet self-management (first and fifth months) with self-monitoring of blood glucose (SMBG) before class and two-hour post-prandial
  • Participants were encouraged to record their weigh twice daily
  • Primary learning and behavioral outcomes were self-reporting diet and exercise
  • Curriculum content was patient-centered to promote self-management; addressed knowledge, skills and attitudes promoting self-management; provided interactive instruction using problem solving; provided feedback individually that focused on support and encouragement
  • Dietary intake was assessed using three-day food records at baseline and end of study using pictures taken of each meal. The Dutch Eating Behaviour Questionnaire (DEBQ) was used to assess aspects of behavioral and emotional eating patterns.
  • Control group: Received the same information as the intervention group in lecture format provided by the same health care professionals, but the lectures were not participant-focused and educators were not trained in group dynamic and coping skills prior to intervention. Dietary intervention was assessed using the Food Frequency Questionnaire (FFQ) at baseline and end of lectures.

Statistical Analysis

  • Descriptive statistics were used to summarize demographic and clinical variables
  • Paired T-tests were used to assess differences in outcome variables at baseline and at six months within the groups
  • Independent T-tests were used to assess differences in outcome variables at baseline and at six months between the groups
  • SPSS was used, P0.05
  • No power analysis was reported.



Data Collection Summary:

Timing of Measurements

Measures obtained at baseline and post intervention at six months.

Dependent Variables

  • Baseline and six-month follow-up measures were obtained in both groups for:
    • Body weight (kg)
    • BMI (kg/m2)
    • HbA1c (percentage)
    • Fasting blood glucose (FBG, mg per dL)
    • Total cholesterol (TC, mg per dL)
    • Low-density lipoprotein cholesterol (LDL-C, mg per dL)
    • High-density lipoprotein cholesterol (HDL-C, mg per dL)
    • Triglycerides (TG, mg per dL).
  • Other variables: Changes in energy intake (kcal) and consumption of food groups (g) were reported from baseline to six months. Changes in exercise and results from the DEBQ were reported.
Independent Variables

Supportive collaborative education provided in eight three-hour lessons over six months as described above. 
Description of Actual Data Sample:

Initial N

A total of 100 subjects were assigned between the two groups using the stratified random sampling previously described. There were nine males and 41 females in the Support group and eight males and 42 females in the Control group.

Attrition (Final N)

  • N=92
  • An 8% dropout rate overall (N=8), with 4% (N=4) in each group
  • A total of 46 participants per group.

Anthropometrics & Demographics:

 Baseline Support Group (n=50) Control Group (n=50)
 Gender (male/female)   9/41   8/42
 Age (years)   63.2±5.4   61.4±4.8
 Weight (kg)   57.0±11.2   57.8±10.6
 BMI (kg/m2 )   23.5±3.4   24.1±3.8


No significant differences in baseline measures between groups in any of above.




Osaka, Japan.


Summary of Results:

Key Findings

    Baseline (N=46)   Post-six Months (N=46)
 Weight (kg)
  Support group
  Control group
BMI (kg/m2 )
  Support group
  Control group
HbA1c (percentage)
  Support group
  Control group
FBG (mg per dL)
  Support group
  Control group
TC (mg per dL)
  Support group
  Control group
LDL (mg per dL)
  Support group
  Control group
TG (mg per dL)
  Support group
  Control group
HDL (mg per dL)
  Support group
  Control group
Energy intake (kcal)
  Support group
  Control group


* P<0.01 for baseline to six months.

† P<0.01 for Support group vs. Control group at six months.

Other Findings

  • Eating behavior assessed by DEBQ improved for external eating and restrained eating in Support group after intervention (P<0.01)
  • Exercise was similar between groups (minimum three days per week) with no change in energy expenditure post-intervention and no differences between groups post-intervention.
Author Conclusion:

Support group education using collaboration between educators and team members can be effective for improving glycemic control in Japanese people with impaired glucose tolerance.

Funding Source:
Government: Grant from Habikino City and National Health Insurance Federation in Osaka Prefeture
Reviewer Comments:
  • Good design with attempt to control variables
  • Threat to external validity; population validity as study conducted in Japan and may not generalize to U.S.
  • Majority of subjects were older women, making this study a generalization
  • No results past six months, not sure of long-term effects
  • No statistical difference in weight loss between the Support group and Control group, but there appeared to be a clinical difference (5% vs. 2%, respectively), which may have contributed to the improvement in glycemic control between groups.
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? 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? Yes
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? No
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) 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 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? 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? Yes
  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.) 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? 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? 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? 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? 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)? No
  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? No
  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? N/A
  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