MNT: Weight Management (2015)

Citation:
Cottell K, Dorfman L, Straight C, Delmonico M, Lofgren I. The effects of diet education plus light resistance training on coronary heart disease risk factors in community-dwelling older adults. The Journal of Nutrition, Health & Aging, 2011; 15: 762-767. PubMed ID: 22089225
 
Study Design:
Non-Controlled Trial
Class:
D - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
To examine the effects of diet education plus resistance therapy on dietary quality, blood lipid and C-reactive Protein (CRP) concentrations in overweight and obese older adults in a community setting.
Inclusion Criteria:
A convenience sample of older adults attending one of four senior centers in Rhode Island were recruited for the study through flyers, direct mailings and local newspapers. Subjects were eligible for inclusion if:
  1. Aged 55 to 80 years
  2. BMI of 25.0kg/m2 to 39.9kg/m2
  3. Engage in vigorous physical activity at least once per week
  4. Weight stable for the past three months
  5. Able to safely engage in mild to moderate intensity exercise with muscular exertion.
Exclusion Criteria:
Subjects were excluded if:
  • Significant or suspected cognitive impairment
  • Severe hearing loss
  • Speech disorder
  • Visual impairment
  • Any condition that would prohibit safe participation in and exercise program
  • Taking lipid-lowering medication for less than six months or any other medication for less than three weeks.
Description of Study Protocol:
  • Recruitment: Subjects were recruited through the activities of four senior centers and their surrounding community communications such as flyers, direct mail and local newspapers
  • Design: This is an observational study of a community outreach intervention. All participants received the same treatment.
  • Blinding used: No blinding noted.

Intervention

  • Subjects received diet education and participated resistance therapy through 60-minute classes twice per week. The first session included 30 minutes each of diet and exercise and the second session was all exercise each week for eight weeks.
  • Diet education was provided by a registered dietitian weekly for eight weeks and focused on the Dietary Approaches to Stop Hypertension (DASH) diet for weight loss, self-monitoring, eating healthy during holidays and when eating out, recipe modification, understanding food labels and maintenance of the DASH diet
  • Exercise was supervised by a trained exercise physiologist and included upper- and lower-body exercises using light dumbbells, elastic tubing and ankle weight as resistance. Individuals were monitored and resistance adjusted throughout the intervention.

Statistical Analysis

Statistical Package for Social Sciences (version 16.0, 2007, SPSS Inc, Chicago, IL).

  • Power calculation
  • Normality via skewness and kurtosis values
  • Continuous variables as mean ± standard deviation
  • Categorical values as frequencies
  • T-tests
  • Chi-square
  • Alpha =0.05.
Data Collection Summary:

Timing of Measurements

Baseline and eight weeks (post-intervention).

Dependent Variables

  • Height, weight, body mass index (inch to cm, pound to kg, kg/m2)
  • Waist circumference, waist-to-hip ratio (inch to cm)
  • Body composition (bio-electrical impedance analysis; OMRON Fat Loss Monitor model HBF-306C, Omron Health Care Inc., Bannockburn, IL; body fat percentage, kg fat mass, kg lean mass)
  • Blood pressure (mmHg; subjects with blood pressure over 160/100mmHg were not able to participate in testing or resistance training)
  • Total cholesterol (TC; mg per dL)
  • High density lipoprotein cholesterol (HDL-C; mg per dL)
  • Triacylglycerol (TAG, mg per dL)
  • Glucose (mg per dL)
  • C-reactive protein (CRP; mg per L)
  • Nutrition risk assessment (Dietary Screening Tool).

Independent Variables

  • Age
  • Gender
  • Race
  • Education
  • Senior center location
  • Medications and Supplements.

Control Variables

Not applicable.

Description of Actual Data Sample:
  • Initial N: 109 completed baseline data
  • Attrition (final N): 96 (16 male, 80 female)
  • Age: 69.2±6.2 years
  • Ethnicity: 95 white, one Hispanic.
Other Relevant Demographics
Education
  • High school or less: 24 (25%)
  • Some college: 34 (35.4%)
  • Four-year college degree: 19 (19.8%)
  • Post-bachelor's: 19 (19.8%) 
  • Anthropometrics measured as part of the study and not compared for groups.
Location
Rhode Island, USA.

 

Summary of Results:

Key Findings
Statistically significant changes (summarized from tables 2 and 3)

  Baseline Post Intervention P-Value
DST Score (0-100) 66.7±12.0 73.4±10.3 <0.001
TAG (mg/dL) 157.8±79.5 145.9±79.4 0.028
weight (kg) 86.2±13.9 85.2±13.6 <0.001
BMI (kg/m2) 33.5±4.0 33.1±4.1 <0.001
Waist Circ (cm) 100.4±12.1 95.3±11.2 <0.001
Hip Circ (cm) 115.0±9.7 109.7±8.8 <0.001
% fat 43.5±5.0 43.1±5.0 0.005
fat mass (kg) 37.6±7.3 36.8±7.2 <0.001
SBP (mm/Hg) 139.3±16.8 129.9±12.0 <0.001
DBP (mm/Hg) 78.9±6.9 77.1±6.5 0.034

Other Findings

Dietary Screening Tool scores were significantly different between completers and non-completers and from baseline to post-intervention, X2 (2)=20.43, P<0.01 with 25, 48 and 23 subjects classified at baseline as at-risk, possible-risk and not-at-risk respectively, and nine, 47 and 40 at post-intervention, respectively (four subjects moved up two categories, 32 moved up one category, 53 remained in the same category and seven moved down one category).

Author Conclusion:
The primary results of this study indicate that an eight-week, community-based, modified DASH diet education plus resistance training intervention is successful at improving Coronary Heart Disease risk factors in community-dwelling overweight and obese older adults. 
Funding Source:
University/Hospital: University of Rhode Island
Reviewer Comments:
No controls and homogenous study population but clearly shows positive impact of RD diet education and exercise.
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? No
  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? 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
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) No
  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
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? Yes
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? Yes
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.) Yes
  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? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? No
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? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? Yes
  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? Yes
  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? Yes
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? Yes
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