EAL

DM: Prevention of Type 2 Diabetes (2007)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To evaluate attitudes, barriers to adherence, and adoption of dietary advice aimed to reduce risk of type 2 diabetes.

Inclusion Criteria:

First-degree relative of someone with type 2 diabetes
No diagnosis of diabetes as determined by oral glucose tolerance test
No use of medications that affect glucose and lipid metabolism
Body Mass Index (BMI) of =/< 35 kg/m²

Exclusion Criteria:

Not discussed

Description of Study Protocol:

Recruitment

Recruited through questionnaires to their relatives with type 2 diabetes
Advertisements in local newspapers during 1997-1999

Design

Subjects were "allocated by minimization" to one of the three study groups: diet group, diet and exercise group, and control group
After 1 year, the control group was given same diet education
This paper is the report of the diet intervention with all subjects considered one "intervention" group and compared to the control group

Blinding used (if applicable)

Not applicable

Intervention (if applicable)

Two diet education classes were given in group setting at start of study
Diet education was based on the Nordic Nutrition Recommendations which included goals to reduce intake of saturated fatty acids, increase intake of monounsaturated fatty acids/n-3 fatty acids, increase fruits/vegetables, increase intake of low glycemic index carbohydrates, and reduce intake of high glycemic index carbohydrates/sweets
Weight reduction was not primary goal
Only one study group received advice on exercise
Phone calls were made to the study subjects 5-10 times during the year to facilitate adherence

Statistical Analysis

Adoption of dietary advice was studied as a change in dietary frequency data from baseline to 1 year ; Wilcoxon signed rank test was used to study this change
Comparisons of age and BMI was done using unpaired t-test

Data Collection Summary:

Timing of Measurements

A semi-quantitative food frequency questionnaire to evaluate diet adherence was completed by each study subject at baseline and after 1 year
One attitude questionnaire and one barrier questionnaire was completed by each study subject after 1 year

Dependent Variables

Attitudes, barriers and dietary adherence

Independent Variables

Diet education

Control Variables

Not discussed

Description of Actual Data Sample:

Initial N: 77 fulfilled study criteria (25 in diet group; 30 in diet/exercise; 22 in control group)

Attrition (final N): 67 (23 women/44 men)

Age: 25-55 years old

Ethnicity: (Swedish)

Other relevant demographics: none

Anthropometrics: not applicable

Location: Sweden

Summary of Results:

Diet adherence (adoption of advice)

Intake of low-fat milk products (yogurt), rapeseed oil, low-fat cheese and oily fish increased significantly (p<0.01)
Intake of lean meat increased (<0.05)
Intake of low-fat milk, fruit and fiber rich vegetables did not change significantly however portion size of fiber rich vegetables increased (p=0.01)
Intake of potatoes, white bread, cakes and cookies decreased significantly (p<0.01) and portion size of potatoes decreased (p<0.001)
Frequencies of pasta, parboiled rice, low-glycemic index cereal and whole kernel bread increased (p<0.01)
Frequencies of beans increased (p<0.05)

Attitudes to diet education

Attitudes were mostly positive regarding diet education (recommendations): eating more beans and lentils was identified difficult/definitely a problem for most subjects

Barriers to diet education

The most important barriers identified to adopting various food changes were 'forgetfulness- reverting to old habits' (~60% of subjects)
The barrier 'low availability in lunch restaurant' was mentioned by ~50% of subjects
Lack of ideas for meals/cooking and family dislikes recommended food were identified by >30% of subjects

Author Conclusion:

Advice aimed at reducing risk of type 2 diabetes was generally well received and adopted in those subjects at risk for type 2 diabetes. There was a large variation in individual attitudes. Healthcare workers can influence the most prevalent barriers.

Funding Source:

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?		???
	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?	???
	2.4.	Were the subjects/patients a representative sample of the relevant population?	???
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?	???
	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%.)	???
	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?		N/A
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	N/A
	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?	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?	???
	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?		???
	7.1.	Were primary and secondary endpoints described and relevant to the question?	No
	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?	???
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	No
	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)?	N/A
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	N/A
	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?		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