Mediterranean Diet and the Prevention and Treatment of CVD
To study the effectiveness of the Mediterranean Lifestyle Program, a comprehensive lifestyle self-management program (Mediterranean low-saturated-fat diet, stress management training, exercise, group support and smoking cessation), in reducing cardiovascular risk factors in post-menopausal women with type 2 diabetes.
- Female
- Diagnosis of type 2 diabetes for at least six months
- Post-menopausal
- Living independently
- Having a telephone
- Able to speak English
- Not developmentally disabled
- Living within 30 miles of Eugene, Oregon.
- Being under 75 years of age
- Planning to move from the area within the study's time span.
Recruitment
Letter was sent to eligible participants from their primary care providers, followed by a follow-up phone call inviting them to participate.
Design
- Participants were randomized to either a usual care or treatment (MLP) condition
- MLP participants took part in an initial three-day retreat, followed by six months of weekly meetings to learn and practice program componenets.
Blinding Used
No.
Intervention
- Mediterrean Lifestyle Program (MLP), which addressed diet, physical activity, stress management, social support and smoking
- The program context, materials, logo, music, intervention space and key components (including diet) were designed to produce a "Mediterranean feel"
- To build a sense of community, a social support intervention delivered by professional and lay leaders was included.
Statistical Analysis
- ANOVAS
- MANCOVAS.
Timing of Measurements
- Baseline
- Six months.
Dependent Variables
- HbA1C: Ion-exchange high-performance liquid chromatography, using the BioRad Variant II Instrument
- Plasma fatty acids: Extracted twice with five ml chloroform/methanol and transesterified with boron trifluoride and methanol
- BMI: Converted from morning digital scale
- Waist-to-hip circumference: Hip girth was measured at the maximum circumference of the buttocks. To compute waist-to-hip ratio, waist was measured in centimeters was divided by hips measured in centimeters
- Blood pressure: A random-zero sphygmomanometer, using the Heritage protocol
- Flexibility: Trunk flexion and shoulder range of motion
- Quality of life: Medical Outcomes Study (MOS) Short-Form General Health survey.
Independent Variables
MLP (Meditarranean Lifestyle Program).
Control Variables
Usual care.
- Initial N: 279
- Attrition (final N): 245 (12% attrition rate)
- Age: Post-menopausal women 75 years of age or younger
- Ethnicity: Not stated
- Other relevant demographics: Living within 30 miles of Eugene, Oregon
- Anthropometrics: No differences between groups on these measurements
- Location: Eugene, Oregon.
Variables |
Treatment Group |
Control Group |
Statistical Significance of Group Difference |
|
HbA1C |
Baseline |
7.43 ± 1.3 |
7.40 ±1.48 |
Yes |
6 months | 7.07 ± 1.11 | 7.38 ± 1.33 | ||
Triglyceride |
Baseline |
202.38 ± 149.06 | 171.59 ±110.56 |
No |
6 months |
176.82 ± 113.98 |
157.93 ± 88.2 |
||
Total Cholesterol |
Baseline |
191.57 ±37.84 |
181.77 ±36.69 |
No |
6 months | 187.61 ±35.60 | 180.72 ±39.73 | ||
BMI |
Baseline |
35.34 ±7.93 | 34.87 ±8.20 |
Yes |
6 months |
34.97 ± 7.85 |
35.07 ±7.85 |
Other Findings
- Six-month differences on serum lipids between UC and MLP did not acheive statistical significance, but favored the MLP condition
- MANCOVA across all quality-of-life dimensions revealed overall improvements in favor of the MLP participants
- MLP participants' blood pressure and flexibility improved and UC participants' conditions slightly worsened
- MANCOVA for the plasma fatty acid profile neared statistical significance (P=0.059).
- The authors did demonstrate that the MLP produced consistent and significant greater improvements than the UC in all the five targeted behavioral risk factors: Eating patterns, physical activity, social support, stress management and coping, smoking cessation.
- The authors did state their limitations in ethnic diversity, even though their sample was heterogenous in socio-economics, income, education and 96% covered by medical insurance
- The authors also stated that they reduced the intensity of their MLP from their initial study because of the inverse relation between program intensity and reach.
Government: | NHLBI |
- This research article was very organized in its written delivery, stated clinical improvements and limitations and also stated other research questions to pursue
- The authors were very honest about the concerns with intensity of an MLP and participation interest also.
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? | ??? | |
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? | ??? | |
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.) | 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%.) | 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? | No | |
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.) | No | |
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? | ??? | |
6.6. | Were extra or unplanned treatments described? | ??? | |
6.7. | Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? | ??? | |
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? | ??? | |
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)? | ??? | |
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 | |