DM: Prevention of Type 2 Diabetes (2007)
- The purpose of this paper was to report the results of post hoc analyses on the role of leisure-time physical activity (LTPA) in the prevention of type 2 diabetes in the Finnish Diabetes Prevention Study.
- Age 40-65
- Impaired glucose tolerance
- Overweight or obese
- Not discussed in this paper.
Recruitment
- Not discussed in this paper.
Design
- Randomized controlled clinical trail.
Blinding used (if applicable)
- Not applicable
Intervention (if applicable)
- The intervention group was given detailed advice on how to achieve goals of the intervention (exercise, weight reduction, diet). No-cost, supervised circuit-type training was offered.
- The control group was given general verbal and written information about diet and exercise but no specific programs were offered.
Statistical Analysis
- Two-sided t tests and X2 tests were used to analyze the differences between groups at baseline and during the follow-up.
- Baseline total LTPA was subtracted from follow-up measures of LTPA to determine change in LTPA.
- Baseline measures of dietary assessment and biochemical assessments were considered when determining change in these measures from the follow-up assessments.
- Statistical significance was defined as P<0.05.
Timing of Measurements
- At baseline and yearly follow-up visits the following were completed: LTPA questionnaire, oral glucose tolerance test, 3-day food records, biochemical assessments (including glucose values and lipids).
Dependent Variables
- Diagnosis of diabetes based on biochemical assessments.
Independent Variables
- Study group assignment.
- Participation in lifestyle interventions.
Control Variables
- Baseline metabolic values
- Changes in dietary intake
- Changes in body mass index
Initial N: 522
Attrition (final N): 487 completed a LTPA questionnaire at baseline and at least once during the follow-up period
Age: 40-65
Ethnicity: Finnish
Other relevant demographics: 61/67% had family history of diabetes in the control and intervention group, respectively.
Anthropometrics : Baseline characteristics were similar between both study groups.
Location: Finland
Variables |
Intervention Group Means and confidence intervals |
Control group Means and confidence intervals |
Statistical Significance of Group Difference |
Total LTPA |
0.4±5.2 (-0.3 to 1.1) |
-0.1±5.3 (-0.7 to 0.6) | 0.36 |
Moderate and vigorous |
0.8±2.7 (0.4 to 1.1) |
0.2±2.9 (-0.2 to 0.6) |
0.028 |
Low intensity |
-0.4±4.6 (-1.0 to 0.2) |
0.3±4.5 (-0.9 to 0.4) |
0.79 |
Strenuous structured (other than walking) | -0.6±1.4 (-0.5 to 0.8) | -0.1±1.3 (-0.2 to 0.1) | <0.001 |
Nonstrenuous structured | -0.1±1.1 (-0.3 to 0.0) | 0.0±0.9 (-0.1 to 0.2) | 0.063 |
Walking for exercise | 0.2±2.1 (-0.1 to 0.5) | 0.3±2.1(0.0 to 0.5) | 0.91 |
Other Findings
- Relative risk of developing diabetes during the trial period was analyzed according to tertiles of change in LTPA. The statistical model that controlled for the most variables found 66% risk reduction in those that increased total LTPA an average of 3.8 hours per week and 48% risk reduction in those that increased total LTPA an average of 0.5 hours per week (P<0.001 for trend).
Quality Criteria Checklist: Primary Research
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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? | 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? | ??? | |
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? | 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.) | ??? | |
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? | No | |
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? | N/A | |
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? | 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)? | 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? | Yes | |
10.2. | Was the study free from apparent conflict of interest? | Yes | |