DM: Physical Activity (2007)

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To evaluate the short- and long-term effectiveness of a brief, tailored, self-management program on multiple outcomes including fat-related eating patterns, physical activity levels, physiological indices, BMI, and waist circumference.
Inclusion Criteria:
  • age 40-70 with Type 2 diabetes
  • BMI > 25
  • stable DM, but sub-optimal
  • able to participate in a regular walking program
Exclusion Criteria:
none specified
Description of Study Protocol:

Recruitment  Eligible patients were identified from a diabetes center database and sent a letter inviting them to participate.  Those who responded positively underwent further screening and were given more information about the study over the telephone.

Design Participants were stratified by insulin use and allocated randomly to either an intervention or a usual care control group using a computer-generated random numbers table.

Blinding used (if applicable) the interventionist was not told of the participants scores on the other outcome measures

Intervention (if applicable)

  • stages of change change for dietary fat reduction assessed using the lamb and Sissons Joshi measure (6 items)
  • stages of change for physical activity assessed using the 11-item Physician-based Assessement and Counseling for Physical Activity (PACE) measure.
  • barriers to healy eating and physical activity assessed using the Barriers to Diabetes Self-Care Scale; 31 items.
  • individual self-efficacy for performing physical activity (one item) and cutting down on intake of high fat food (one item) was assess based on Lorig et al's 1996 guidelines.
  • Based on the results the interventionist drafted a personalized self-management plan for each participant
  • participants met with interventionist to develop their personalized self-management plan and set one dietary goal and one physical activity goal
  • ambivalence about behavior change was explored using Miller and Rollnick's brief motivational interviewing principles.
  • follow-up phone calls at one, three, and seven weeks post assessment
  • meeting with interventionist at 12 and 24 weeks to review goals and problem-solve

Statistical Analysis

  • a series of repeated measures MANOVAS with a within-subject factor of time (three levels) and a between-subject factor of group (two levels) were conducted to evaluate the intervention effects on dietary behavior, physical activity, physiological outcomes and self-care activities
  • univariate ANOVAS and independent and paired t-tests were conducted where appropriate on each dependent variable as follow-up tests to the MANOVAS.
  • familywise error rate across these tests was controlled for using Holm's sequential Bonferroni approach


Data Collection Summary:

Timing of Measurements  Baseline assessment using the above inventories; full assessment repeated at 12, 24, and 52 weeks.

Dependent Variables

  • diabetes self-management was assessed using 8 items from the Summary of Diabetes Self-Care Activities Quesionnaire
  • four dimensions of fat-related dietary habits were assessed using the Kristal Food habits Questionnaire (FHQ: 20 items)
  • Block Fat Screener identifies high daily intake of dietary fat (15 items)
  • Physical Activty Scale for the Elderly Questionnaire (PASE: 10 items)
  • weight, BMI
  • waist circumference
  • serum lipids
  • HbA1c 

Independent Variables

  • Intervention or usual care

Control Variables


Description of Actual Data Sample:

Initial N: 573 patients received letter; 357 replies with overal response rate of 62.3%; of the replies 57.7% were interested in participating and underwent telephone screening (n= 207).  Forty were too ill to participate, 66 more declined to participante.  A total of 100 patients were randomized into the study, which is 60.2% of the 166 eligible patients who were interested in participating.

Attrition (final N): 94

Age: average 59.5 years

Ethnicity: not specified

Other relevant demographics: 58% men; no significant differences between the intervention and control groups

Anthropometrics: average BMI 31±3.99; waist circumference 103 cm ± 10.35 cm; HbA1c 8.4% ±1.64;

Location: United Kingdom


Summary of Results:



Tailored Intervention Group



Usual Care group

     Statistical Significance Between Groups  
  Baseline 3 months 12 months Baseline 3 months 12 months 3 months 12 months

Dietary behavior;

   FHQ: substitutea


2.60±0.62 1.35±0.58**c 1.36±0.58 2.43±0.70 1.68±0.68**c 1.62±0.66 P=.010 NS

Dietary behavior;FHQ:modify meata


1.08±0.50  1.21±0.60


1.40±0.72  1.44±0.65 



Dietary behavior: block fat screenera


23.62±14.13**c 20.97±12.97**c 


26.03 ±18.78 31.24±23.14 


Physical activity: PASEb  254.30±95.23 275.78±110.05  281.35±114.84   260.05±100.31 241.36±85.60  246.60±92.82   NS NS
BMI  32.40±4.49 32.26±4.47 32.06±4.30  31.30±5.01  31.34±5.08  32.72±4.77**d  NS NS
Waist, cm  104.22±10.46 102.92±10.35*c  102.70±10.25*d   101.25±11.44 101.87±10.86  103.60±10.63   NS NS
Self-care activities: dietb  3.72±0.57 4.06±0.57 **c 3.82±0.52   3.80±0.56 3.83±0.48  3.64±0.98   NS NS

Self-care Activities: physical activityb

 2.37±1.21 3.40±1.11 **c 3.24±1.47 **d  2.51±1.28 2.83±1.16  2.57±1.38  P= .037 P=.021

*P<.01; **P< .001 

a higher scores worse

b higher scores better

c significant difference between baseline and 3 months

d significant difference between 3 months and 12 months

Other Findings

There were no significant interactions for cholesterol, HDL, LDL, triglycerides or HbA1c (P=.399).


Author Conclusion:

The intervention was effective in producing reported dietary change.  The intervention participants made significant reductions to their fat-related eating habits between the baseline and three-month assessments, and these changes were maintained at 12 months.

The intervention had less impact on physical activity.

The reported changes in lifestyle behaviors were confirmed by the objective measure of waist circumference and BMI, both of which decreased significantly from baseline in the intervention group, while BMI increased in the control group.

The behavior changes did not translate into significant changes in HbA1c or serum lipids.

Funding Source:
Reviewer Comments:

Of 573 patients who were invited to participate, only 100 eventually did so, with many non-responders and persons who chose not to participate.  Therefore this sample represents only the most motivated individuals.

Inclusion and exclusion criteria were vague,  e.g. some prospective participants were "not healthy enough" to participate; inclusion criteria included "stable, but not optimal DM."

All changes in behavior were based on self-report, with waist circumference and BMI as the only objective measures that showed any significant changes.


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? 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? No
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? 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? Yes
  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? ???
  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? ???
  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)? Yes
  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? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes