Risk of Developing Metabolic Syndrome

Citation:

Pitsavos C, Panagiotakos DB, Chrysohoou C, Papaioannou I, Papadimitriou L, Tousoulis D, Stefanadis C, Toutouzas P. The adoption of Mediterranean diet attenuates the development of acute coronary syndromes in people with the metabolic syndrome. Nutr J. 2003 Mar 19; 2: 1.
 

PubMed ID: 12740043
 
Study Design:
Case controlled
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To investigate the effect of the Mediterranean diet in with Metabolic Syndrome on risk of acute coronary syndromes.

Inclusion Criteria:

Cases:
Hospitalized for 1st event of CHD between Jan 2000-Aug 2001 for:
1. 1st event of MI

2. Dx of Unstable angina

Agreed to participate in study

Controls:

Visited outpatient clinic in same hopitals during same time period.

1. Cardiovascular disease free (medical chart reviewed by an MD)

2. Age (+/- 3years), gender, region of residence matched to cases.

Exclusion Criteria:

Cases:
 Stable angina was excluded from analysis

Controls:

If they were not matched to subjects or did not have outpatient visits to the same hospital during the time frame they were not included

Description of Study Protocol:

Recruitment :

Cases: hospitalized between 1/2000-8/2001 for a 1st event of coronary heart disease
Controls: randomly selected CVD free subjects who visited the outpatient unit in the same hopital frequency matched to the cases for age, sex, region.

 

Design

Nutrition info was determined from the National School of Public Health's survey, estimated number of servings/week.

Measurements of ATP III risk factors taken during 2nd day of hospitalization for cases and at out-patient visit for controls. 

Other demographics were obtained from medical chart review.

 

Blinding used (if applicable) n/a

 

Intervention (if applicable) n/a

 

Statistical Analysis Mutlivariate logistic regression to determine OR of coronary heart disease in subjects with MS who follow the mediterranean diet.

"pooled-probability value derived from cross-tabulated comparison" between the cases and controls for "classic CVD risk factors (smoking/ physical activity/ hypertension/ hypercholesterolemia/ obesity/ DM stratefied by Mediterranean diet

Data Collection Summary:

Timing of Measurements

All measurements were obtained from the subjects' medical record.

 

Dependent Variables

  • Acute Coronary Syndrome

Independent Variables

 

MS

Table III. National Cholesterol Education Program/ ATP III criteria for Metabolic Syndrome

Risk Factor

Defining Level

Abdominal obesity:

            Men

            Women

Waist circumference

            >102 cm (>40 in)

            > 88 cm (>35 in)

Hypertriglyceridemia

>150 mg/dL (1.69 mmol/L)

Low HDL cholesterol

            Men

            Women

 

<40 mg/dL (1.04 mmol/L)

<50 mg/dL (1.29 mmol/L)

Elevated blood pressure

 >130/85 mm Hg

High fasting glucose

>110 mg/dL (>6.1 mmol/L)

* MS is defined as individuals meeting 3 or more of the listed criteria.

 

 

Mediterranean Diet:  Mediterranean diet as measured by a survey of diet over the past year developed by the National School of Public Health in Greece. Pattern=daily consumption of whole grains, 2-3 servings/day of vegetables, olive oil as the main added fat, dairy 1-2 servings/day, fish 2 X/wk, poultry 3-4 X/wk, olives/pulses (beans)/nuts 3X/wk, potatoes/eggs/sweets 3-4 X/wk, red meat 3X/month, 1-2 glasses wine/day, and a mono: sat fat ratio of 2.

Control Variables

gender, family history of CVD, Diabetes, smoking, physical activity, obesity (dicotomous), income, age,

Description of Actual Data Sample:

Initial N:

cases: 848 agreed to participate, reponse rate = 89%.  307 had MS

658 males, 190 women

controls: 1,078, reponse rate = 83%    198 had MS

830 men, 248 women

Attrition (final N): not discussed

Agecases matched to controls +/- 3 years

Ethnicity: Greece, white

Other relevant demographics:

Anthropometrics (e.g., were groups same or different on important measures)

Location: Represented all the major regions of Greece.

 

Summary of Results:

Descriptive analysis:

50% of controls and 60% of pts with MS had a sedentary lifestyle (p=0.24).

Current smoking habits were associated with prevalence of the MS in pts and controls (p<0.001)

26% of pts with the MS and 35% controls with the MS were closer to the Mediterranean diet (p<0.01).

Variables

Those with Acute Coronary Disease and Metabolic Syndrome

Measures and confidence intervals

Control group no CVD and Metabolic Syndrome

Measures and confidence intervals

Statistical Significance of Group Difference

Follow Med. Diet

Controlled for other variables

OR = 0.77

CI: 0.6450-0.918

 

 

unadjusted

OR= 0.64

CI: 0.44-0.95

 

 

Being physically acive vs sedentary    

OR= 0.89

CI: 0.839-0.945

 

 

Other Findings

The MS increased risk of CVD by 2 x's. (OR=2.35, CI: 1.87-2.84)

Adoption of the Mediet by people who reported they exercised at least once per week (>4 Kcal/min) was associated witrh a 47% reduced risk of developing ACS (OR: 0.53, P<0.01) after adjustments.

Author Conclusion:

"This is the first study concerning prevalence of the metabolic syndrome in Greece and the effect of the Mediterranean diet on the related coronary risk"

1. One third of the acute coronary events could be eliminated by adoption of the med. diet in subjects with MS

2. Physicians need training to identify MS in patients.

3. Early identification/ detection of MS important

Funding Source:
Government: National Statistic Service
Not-for-profit
0
Foundation associated with industry:
In-Kind support reported by Industry: Yes
Reviewer Comments:

Because of the case controlled design it is difficult to avoid recall bias.  It is also difficult to understand if the nutrition survey had the percision to assess long-term diet.

Because such a small number had the MS in each group, and the primary analysis was based on only these subjects, it is unclear if they have enough power to determine anything significant.

The title gives the impression that the study is on MS, but this is a small # of the subjects. 

 

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) N/A
  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) N/A
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? 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
  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) N/A
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) N/A
 
Validity Questions
  1. Was the research question clearly stated? N/A
1. Was the research question clearly stated? N/A
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? 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
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
  1.3. Were the target population and setting specified? Yes
  2. Was the selection of study subjects/patients free from bias? N/A
2. Was the selection of study subjects/patients free from bias? N/A
  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
  2.1. 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
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? 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
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
  3. Were study groups comparable? N/A
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
  3.1. 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? 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
  3.3. 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? ???
  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? ???
  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.) ???
  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.) ???
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? 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? N/A
4. Was method of handling withdrawals described? N/A
  4.1. Were follow-up methods described and the same for all groups? N/A
  4.1. Were follow-up methods described and the same for all groups? N/A
  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
  4.2. 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? ???
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? ???
  4.4. Were reasons for withdrawals similar across groups? N/A
  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
  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. 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
  5.1. 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
  5.2. 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? No
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? No
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? Yes
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? Yes
  5.5. In diagnostic study, were test results blinded to patient history and other test results? 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? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? N/A
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  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? N/A
  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? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? N/A
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments described? N/A
  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
  6.7. 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
  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? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? N/A
  7.1. Were primary and secondary endpoints described and relevant to the question? 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
  7.2. 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? N/A
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? N/A
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? 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? ???
  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? ???
  7.6. Were other factors accounted for (measured) that could affect outcomes? ???
  7.7. Were the measurements conducted consistently across groups? 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? N/A
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? N/A
  8.1. Were statistical analyses adequately described and the results reported appropriately? 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
  8.2. 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
  8.3. 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
  8.4. 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
  8.5. 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
  8.6. 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
  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? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? N/A
  9.1. Is there a discussion of findings? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
  10. Is bias due to study's funding or sponsorship unlikely? N/A
10. Is bias due to study's funding or sponsorship unlikely? N/A
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes
  10.2. Was the study free from apparent conflict of interest? Yes