Risk of Developing Metabolic Syndrome

Citation:

Irwin ML, Ainsworth BE, Mayer-Davis EJ, Addy CL, Pate RR, Durstine JL.Physical activity and the metabolic syndrome in a tri-ethnic sample of women. Obes Res. 2002 Oct; 10 (10): 1,030-1,037.

PubMed ID: 12376584
 
Study Design:
Cross-Sectional Study
Class:
D - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
To determine the association between Physical Activity (PA), both vigorous and moderate intensity as well as maximal treadmill test and Metabolic Syndrome (MS) as defined by the ATP III guidelines in a African American, Native American, and white women.
Inclusion Criteria:

Inclusion criteria:

All were 40 years or older. 

All had ability to read and write well enough to record activity in PA records.


1. African American women from South Carolina (n=57)

2. Native American women from Pueblo or Navajo Nation in NM (n=50)

3. White women from South Carolina and NM (n=25)

 

Exclusion Criteria:

Exclusion:

1. Physical illness or disability that would limit daily PA.

2. Taking insulin (n=1)

3. Incomplete PA records (n=13)

 

Description of Study Protocol:

Recruitment

Recruited with advertisements.

 

Design

Cross sectional

Blinding used (if applicable)

n/a

Intervention (if applicable)

n/a

Statistical Analysis

General ized linear models to determine significant differences in demographics and metabolic variables by ethnicity.

Multiple linear regression to determine odds of MS across quartiles of PA, using the lowest quartile (the least active) as the reference.

Multiple linear regression to determine odds of MS for maximal tredmill duration as a continuous variable.

Interaction terms (PA X ethnicity) were also tested.

Data Collection Summary:

Timing of Measurements

PA logs were completed for 4 days, 2 X  one month apart

Dependent Variables

  • MS as defined by ATPIII

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.

Independent Variables

Self reported PA: Subjects reported duration, purpose, type, and perceived intensity METs were determined based on the "Compendium of Physical Activity". METs were then summed as METs minutes/day (MET minute= 1 kcal/min for a 60 kg person).

Intensity determined as MET minutes/day by Centers for Disease Control and Prevention standards.

Moderate- 3-6 METS

Vigorous- >6 METS

Maximal Treadmill Test:

Subjects's time to exhaustion on a treadmill graded exercise test. A Pilot was done to insure that all subjects would reach fatigue by 26 minutes.

 

Control Variables

age/enthicity/study site/menopause/use of hormone replacement

Description of Actual Data Sample:

Initial N: 160

Attrition (final N): 13 removed for incomplete records, 1 for being on insulin

Age: All 54.6 +/-0.9, African American 56.7 +/- 1.5, Native American 51.4 +/- 1.6 (sign. different than African American women p<.005), White women 55.5 +/- 1.5

Ethnicity: see above

Other relevant demographics: There was a statistically significant difference in the following demographics:
1. African American women were significantly taller and heavier and higher BMI than the Native American and white women.

2. African American women had significantly higher systolic blood pressure, HDL, and significantly lower triglycerides than the Native Americans and white women.

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

Location: as above

 

Summary of Results:

All OR were adjusted for age, ethnicity, site, meonpausal status, use of hormone-replacement therapy.

Maximal treadmill duration quartiles,  compared to reference group (see below)

 Treadmill duration quartiles in METS

Measures and confidence intervals

Treadmill duration quartiles in minutes

Measures and confidence intervals

Statistical Significance of Group Difference

MS compared to shortest time (4.4 m-10.0 min)

7.6-8.5 METS group

0.48 (0.17-1.40)

10.1-13.0 minutes

0.23 (0.07-0.74)

METS group

p=0.006 for trend

MS compared to least exertion (4.5-7.5 METS) as reference

8.6-10.5 METS group

0.37 (0.11-1.2)

13.1-16.0 minutes

0.13 (0.04-0.48)

Minutes group

p=0.0004 for trend

MS

10.6-14.5 METS group

0.08 (0.01-0.66)

16.1-26.0 minutes

0.07 (0.02-0.35)

 

PA (based on records) quartiles compared to reference groups see below

Moderate intensity activity

(MET min/d)

Vigorous activity

(MET min/d)

Statistical Significance of Group Difference

MS  compared to 18-21.5 MET min/d reference group for moderate intensity

216-337

0.78 (0.21-2.92)

0.1-30

0.66 (0.20-2.16)

Stat signif difference between groups

p=0.010 for trend for both

MS compared to 0 MET min/d reference for vigorous activity

338-490

0.56 (0.13-2.35)

31-119

0.42 (0.11-1.63)

 

 

491-1351

0.18 (0.03-0.90)

120-1351

0.14 (0.02-1.2)

Other Findings

 

Author Conclusion:

"This study indicates that higher levels of moderate-intensity PA, vigorous intensity PA, and greater maximal treadmill duration are inversely associated with the metabolic syndrome among an ethnically diverse sample of women"

Funding Source:
Government: NIH (Grant: NIH WHI-SIP No. 22W-U48/CCU409664)
Reviewer Comments:

Results were well presented and clear.  The adjustments for enthnicity and other demographics were well explained.

Conclusions and discussion were thorough.

 

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
  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
  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) 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. Was the research question clearly stated? Yes
  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? ???
  2.4. Were the subjects/patients a representative sample of the relevant population? ???
  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.) 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? 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? Yes
  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
  3.5. 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
  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%.) 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%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  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
  4.4. 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? ???
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? ???
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? 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
  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? N/A
  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? 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? 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
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  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? ???
  8.6. Was clinical significance as well as statistical significance reported? ???
  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? No
  10.1. Were sources of funding and investigators' affiliations described? No
  10.2. Was the study free from apparent conflict of interest? Yes
  10.2. Was the study free from apparent conflict of interest? Yes