The EAL is seeking RDNs and NDTRs who work with patients, clients, or the public to treat children and adolescents living with type 1 diabetes, for participation in a usability test and focus group. Interested participants should email a professional resume to by July 15, 2024.

MNT: RDN in Medical Team (2015)

Duijzer G, Haveman-Nies A, Jansen S, ter Beek J, Hiddink G, Feskens E. Feasibility and potential impact of the adapted SLIM diabetes prevention intervention in a Dutch real-life setting: the SLIMMER pilot study. Patient Education and Counseling, 2014; 97: 101-107. PubMed ID: 24993840
Study Design:
Before-After Study
D - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
To describe the pilot-testing of the adapted Study on Lifestyle intervention and Impaired glucose tolerance Maastricht (SLIM) to determine its feasibility and likelihood of achieving desired impact.
Inclusion Criteria:
  • Aged 40 to 65 years
  • Impaired fasting glucose.
Exclusion Criteria:
  • Not being able to speak and understand the Dutch language
  • Cognitive dysfunction
  • Any comorbidity that made participation in a lifestyle intervention impossible.
Description of Study Protocol:


Participants were recruited by three general practitioners from their patient registration database.


A 10-month pilot intervention study using a one-group pre-test post-test design with ongoing process measures.


The intervention consisted of a dietary and physical activity component.

  • Dietary intervention: The objective of the dietary intervention was to adopt a sustainable healthy dietary pattern according to Dutch dietary guidelines. A dietitian gave tailored dietary advice during six individual consultations (30 to 60 minutes per consultation; four hours per participant total). The dietitian also organized one group session aimed at sharing experiences, motivating each other and discussing label-reading.
  • Physical activity intervention: The objective of the physical activity intervention was to increase the physical activity level of the participants to at least 30 minutes per day during at least five days per week. The intervention combined aerobic and resistance exercise program. Weekly group-based training sessions of one hour in duration were supervised by a skilled physiotherapist. Sports groups were formed based on day and time preferences of the subjects and availability of the physiotherapists. Subjects had free access to the training sessions and were stimulated to participate for at least one hour per week.
  • Subjects were also encouraged to drink less alcohol and to quit smoking if necessary.

Statistical Analysis

Independent samples T-tests, paired samples T-tests, McNemar’s chi-squate tests, Wilcoxon signed-rank tests and Cohen’s D were used, as appropriate.

Data Collection Summary:

Timing of Measurements

Measures were performed at baseline and at the end of the intervention.

Dependent Variables

  • Fasting plasma glucose
  • Blood pressure
  • Body weight
  • BMI
  • Waist circumference
  • Hip circumference
  • Medication use
  • VO2max
  • Perceived health
  • Smoking
  • Physical activity
  • Alcohol intake
  • Fruit intake
  • Vegetable intake
  • Reach of intervention: The proportion of intended target audience that participated in the intervention
  • Acceptability of intervention: The extent to which participants and health care professionals are satisfied with the intervention
  • Implementation integrity of intervention: The extent to which the intervention was implemented as planned
  • Applicability of intervention: The extent to which an intervention process can be implemented in the real-life setting.

Independent Variables

Dietary intervention and physical activity intervention.

Control Variables

  • Gender
  • Age
  • Perceived health
  • Education level.
Description of Actual Data Sample:
  • Initial N: 31 (15 male, 16 female)
  • Attrition (final N): 29 (7% dropout rate)
  • Age: Average, 54 years old
  • Ethnicity: 93% Dutch natives.

Other relevant demographics:

  • 46% had a low level of education
  • 63% had a family history of diabetes.

Not described.

Apeldoorn, Netherlands.

Summary of Results:

Key Findings

  • Self-reported days of physical activity increased from four to five (P=0.005)
  • On average, body weight was 3.5kg lower (P=0.005)
  • Waist circumference was reduced by 4.2cm (P=0.001)
  • Hip circumference was reduced by 2.8cm (P=0.005)
  • Diastolic blood pressure was reduced by 5.9mmHg (P=0.001)
  • VO2max improved by 0.4 L per minute (P<0.001)
  • Perceived health increased significantly (P=0.005)
  • Participants and professionals were satisfied with the intervention program.
Author Conclusion:
  • Implementation of the SLIMMER diabetes prevention intervention is feasible in a Dutch real-life setting and it is likely to achieve the desired impact
  • Practicing and optimizing the intervention creates local support among stakeholders.
Funding Source:
Government: Netherlands Organization for Health Research and Development; Dutch Diabetes
Dutch Diabetes Research Foundation
Other non-profit:
Reviewer Comments:
  • Small study size
  • All data collected by one researcher, which could cause subjectivity in qualitative data interpretation.
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? N/A
  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? N/A
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  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%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? N/A
  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? Yes
  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? N/A
  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? N/A
  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)? Yes
  8.6. Was clinical significance as well as statistical significance reported? N/A
  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? Yes
  10.2. Was the study free from apparent conflict of interest? Yes