NC: Diabetes Management (2007)

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
  • The purpose of the study was to evaluate longer-term effects of a Mediterranean lifestyle program
  • The main hypothesis was that those participants in the MLP, compared to the usual care (UC) condition, would show greater 12- and 24-month improvements in targeted lifestyle behaviors, including eating patterns, physical activity, stress management and psycho-social variables, including perceived social support, problem-solving, self-efficacy and quality of life.
Inclusion Criteria:

Women were recruited from primary care clinics with the following criteria:

  • Having type 2 diabetes for at least six months
  • Post-menopausal
  • Living independently
  • Having a telephone
  • Ability to read English
  • Not being developmentally disabled
  • Living within 30 miles of the intervention site (Eugene, OR, USA).
Exclusion Criteria:

Women were excluded if:

  • Older than 75 years of age
  • Planning to move away from the area within the study's time span.
Description of Study Protocol:


  • A total of 279 post-menopausal women with type 2 diabetes, who were patients of participating primary care clinics, were recruited for the study
  • All patients that met inclusion criteria were sent letters from their primary care providers, followed by phone calls inviting them to participate
  • 51% of eligibile women contacted agreed to participate in the study.


  • The basis of the MLP program combined Social Cognitive Theory, Goal Systems and Social Ecological Theory
  • This model included social support.

Blinding Used



  • The MLP was delivered by an RD, an exercise physiologist, a stress management instructor and a combination of professional and lay support group leaders
  • The program started with a 2.5-day non-residential retreat, which was followed by four-hour weekly meetings consisting of topics of physical activity, stress management and support group
  • The intervention was conducted in four sequential waves two months apart, with approximately 40 treatment condition and 30 control condition participants in each wave.

Statistical Analysis

  • One-way analyses of variance (ANOVA)
  • Repeated-measures multi-variate analyses of covariance (MANCOVA)
  • Follow-up univariate analyses of covariance (ANCOVA).
Data Collection Summary:

Timing of Measurements

Baseline, six, 12 and 24 months.

Dependent Variables

  • Diet: FFQ (Food Frequency Questionnaire) and saturated fatty acids from plasma fatty acid profile
  • Physical activity: The CHAMPS Activities Questionnaire for Older Adults scale and seven days with the Yamax DW-500 pedometer to record the number of steps taken daily were averaged for the four study time points 
  • Stress management: Self-monitoring form consisting of number of minutes of stretching, breathing or medication or visualization for each of seven days
  • Social desirability: Balanced Inventory of Desirable Responding
  • Social resources: The Brief Chronic Illness Resources Survey (CIRS)
  • Problem-solving ability: The Diabetes Problem-Solving Interview
  • Self-efficacy: Confidence in Overcoming Challenges to Self-Care and Sallis Self-Efficacy for Diet and Exercise Behavor instrument
  • Depression: Center for Epidemiologic Studies Depression Scale (CES-D)
  • Perceived stress: Perceived Stress Scale
  • Quality of life: The Diabetes Distress Scale (DDS).

Independent Variables

Mediterranean Lifestyle Program (MLP), which consisted of healthful eating, physical activity, stress management, smoking sensation and social support.

Control Variables

Usual care in primary care practice.

Description of Actual Data Sample:
  • Initial N
    • Usual Care: 116
    • MLP: 163.
  • Attrition (final N): 237 (85%)
  • Age
    • Usual Care: 60.7
    • MLP: 61.1.
  • Ethnicity: Primarily Caucasian
  • Other relevant demographics: Homogenous in income, education level, present living arrangement
  • Anthropometrics: Similar in weight, BMI, age diagnosed with diabetes, years taking diabetic medications
  • Location: Eugene, Oregon.
Summary of Results:


Treatment Group
Measures and confidence intervals

Control Group
Measures and confidence intervals

Statistical Significance of Group Difference

Diet (Percentage of Calories from Fat)

12 months




24 months 0.11 0.12

Physical Activity (kcal/kg/hour Moderate Activity)

12 months 7.69 6.39


24 months



Stress Management (Daily Practice Minutes)

12 months




24 months 16.8 11.0
Flexibility (Sit-and -Reach Percentage Score) 12 months 32.2 28.6 Yes
24 months



Social Support (UCLA Negative Summary Score) 12 months



24 months 3.99 3.99
Social Support (UCLA Positive Summary Score) 12 months 3.28 3.00 Yes
24 months



Self Efficacy for Diet and Exercise 12 months



24 months 4.1 3.8
Quality of Problem-Solving 12 months 4.1 3.9 Yes
24 months



Other Findings

  • From an RE-AIM perspective, the MLP produced strong Reach, Adoption, Effectiveness and Maintenance results
  • The MLP produced enhancements rather than decrements in quality of life, an important finding with a program requiring a significant time committment.
Author Conclusion:
  • The MLP produced consistent and significantly greater long-term (12- and 24-month) improvements than the UC in all of the four CHD behavioral risk factors: Eating patterns, physical activity, perceived social support and stress management and in percentage calories ingested from saturated fat, frequency, duration and intensity of moderate-intensity exercise, flexibility and number of daily minutes they practiced stress-management techniques and problem-solving skills
  • The authors stated the strengths of the program were that the sample of high-risk females were a general representation, that the sample was randomized, many measures were employed, intensive intervention, extended length of follow up and the ability to retain 85% of the participants
  • They also stated that because of a higher cost with the MLP, cost-conscious health care systems may not be interested in implementing this program.
Funding Source:
Government: National Heart, Lung, and Blood Institute (ROI HL62156)
Reviewer Comments:
  • The authors demonstrated significant improvements in lifestyle and health outcomes with 12 to 24 months of MLP, as compared to usual care
  • Many behavioral markers, as opposed to just clinical markers, were measured, such as stress management, quality of life, self-efficacy and social support, which may be better indicators of long-term health changes
  • They did a thorough and organized discussion of their findings, strengths and limitations.
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? N/A
  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? Yes
  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? ???
  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.) ???
  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? N/A
  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? N/A
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? N/A
  10.2. Was the study free from apparent conflict of interest? Yes