EAL

PDM: Metabolic Syndrome (2013)

Citation:

Cohen BE, Chang AA, Grady D, Kanaya AM. Restorative yoga in adults with metabolic syndrome: A randomized, controlled pilot trial. Metab Syndr Relat Disord. 2008; 6(3): 223-229.

PubMed ID: 18710330

Study Design:

Randomized Controlled Trial

Class:

A - Click here for explanation of classification scheme.

Quality Rating:

POSITIVE: See Quality Criteria Checklist below.

Research Purpose:

To evaluate the feasibility and acceptability of restorative yoga in overweight, underactive adults with metabolic syndrome.

Inclusion Criteria:

Age 30 to 65 years
Met NCEP criteria, three or more of the following:
- Fasting blood sugar (FBS) 100mg per dL or higher, systolic blood pressure (BP) 130mm Hg or higher, diastolic blood pressure 5mm Hg or higher or use of anti-hypertensive medication
- High-density lipoprotein cholesterol (HDL-C) less than 40mg per dL for men or less than 50mg per dL for women
- Triglycerides (TG) 150mg per dL or more
- Waist circumference (WC) 102cm or more for men and 90cm or more for women.

Exclusion Criteria:

Moderate exercise for more than 150 minutes per week
Pregnancy or lactation, coronary heart disease event or hospitalization in the preceding six months, use of medication that affect insulin sensitivity, substance abuse and regular yoga practice
Unstable medical or psychiatric conditions that would limit ability to complete the study.

Description of Study Protocol:

Recruitment

Telephone screen followed by a screening visit to measure BP, WC and FBS, HDL-C and TG.

Design

RCT using four strata defined by sex and race/ethnicity (white vs. nonwhite) using blocks of size two.

Blinding Used

Implied with measurements.

Intervention

Yoga or control group. Yoga group attended a three-hour introductory class followed by 90-minute classes twice weekly during weeks one to five and weekly during weeks six to 10. Classes taught by two certified yoga instructors who used restorative poses that emphasizes relaxation and uses props to provide total support of the body. They were instructed to practice at home for 30 minutes or more three times per week and given a practice log book plus all necessary yoga props, a manual with photos and instructions for each pose and an audio compact disc describing the postures.
Control group received no intervention
Both groups were asked not to make any changes to their diet and exercise regimens during the study.

Statistical Analysis

T-tests for continuous variables and Wilcoxon or chi-squared tests for dichotomous variables. Sensitivity analyses excluded two participants in the control group who started diets during the intervention and yoga person who had uncontrolled diabetes with highly variable glucose values.

Data Collection Summary:

Timing of Measurements

Baseline and week 10.

Dependent Variables

Feasibility: Number of phone and in-person screening visits and rate of participant recruitment
Adherence: Attendance at yoga classes, self-reported frequency of and duration of home yoga practice
Acceptability: Interview at final yoga class and questionnaires at final visit
Height and weight: Light clothing without shoes
WC: Twice with a flexible tape measure midway between the lowest rib and iliac crest
BP: Twice after seated for five minutes or more; mean used
Insulin sensitivity index: Matsuda equation used after a 75g glucose drink and blood taken at zero, 30, 60, 90 and 120 minutes
Plasma glucose: Automated analyzer with immobilized enzyme biosensor
Plasma insulin: In duplicate by radioimmunoassay
TG and HDL-C: Enzymatic calorimetric methods
LDL-C: Calculated using Friedewald's formula
Stress: Cohen's Perceived Stress Scale
Macronutrient intake: 2005 Block Food Frequency Questionnaire
Physical activity: Validated 24-item questionnaire rating hourly participation in various activities over previous four weeks
Energy level and psychological well-being: Validated sub-scales of the Medical Outcomes Study Short-Form 36-Item Health Survey (SF-36)
Depression: 10-item Center for Epidemiologic Studies Depression Scale (CES-D)
Overall health: Five-point Likert scale from "poor" to "excellent" by participant's rating.

Independent Variables

Yoga or control group. Yoga group attended a three-hour introductory class followed by 90-minute classes twice weekly during weeks one to five and weekly during weeks six to 10. Classes taught by two certified yoga instructors who used restorative poses that emphasizes relaxation and uses props to provide total support of the body. They were instructed to practice at home for 30 minutes or more three times per week and given a practice log book plus all necessary yoga props, a manual with photos and instructions for each pose, and an audio compact disc describing the postures.
Control group received no intervention.

Control Variables

Both groups were asked not to make any changes to their diet and exercise regimens during the study.

Description of Actual Data Sample:

Initial N: 26 (4 males, 22 females)
Attrition (final N): 24
Age: 52±9 years
Ethnicity: 46% white, 54% non-white
Anthropometrics: Participants had an average of 3.5±0.7 metabolic syndrome requirements; all met WC criteria and majority for BP, FBS and HDL-C
Location: San Francisco.

Summary of Results:

Key Findings

Mean number of yoga classes attended was 14±2 (range 11 to 17). The mean home practice time was 117±49 minutes per week.
Feedback from participants was positive with all reported being "very satisfied" with the intervention. A majority (87%) felt that practicing restorative yoga was "very easy" or "moderately easy." No adverse effects were reported. The participants felt the most bothersome part of the study was practicing yoga at home (33%).
There were trends toward improvement in systolic BP (9.2mm Hg difference between the groups; P=0.07) and diastolic BP (4.6mm Hg difference between the groups; P=0.10)
Change in weight favored the yoga group but was not statistically significant. Lab measures did not differ between the groups. Excluding the two controls who violated protocol and one yoga person with uncontrolled diabetes strengthened the trends for less weight gain (P=0.13), lower increase in BMI (P=0.10) and reduced diastolic BP (P=0.07), but did not change the lab results
Changes in fasting glucose, two-hour glucose, HDL cholesterol and triglyceride levels were not significant between groups
Changes in waist circumference were not significant between groups
The yoga group had significant improvements in energy level (P=0.009) and trends towards improvement in psychological well-being (P<0.12) and stress (P<0.22). Change in physical activity and dietary intake from baseline to end of study did not statistically differ between groups.

Author Conclusion:

Restorative yoga was a feasible and acceptable intervention in overweight adults with metabolic syndrome.

Funding Source:

University/Hospital:

UCSF Mt. Zion Fund

Not-for-profit

Cliff Lede foundation

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?		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)	No
	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?	No
	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?	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.)	Yes
	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?	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?	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?	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?	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