HD: Effectiveness of Nutrition Intervention Methods (2010)
To test the effects of a culturally competent dietary self-management intervention on physiological outcomes and dietary behaviors for African Americans with type 2 diabetes in rural South Carolina.
- African American living in rural South Carolina (SC)
- Diagnosis of type 2 diabetes
- 18 years of age or older
- At least one of the modifiable indicators of high-risk diabetes
- AIC 8% or higher
- Cholesterol 200mg per dL or higher
- Triglycerides 200mg per dL or higher
- Low-density lipoprotein (LDL) cholesterol 100mg per dL or higher
- BMI 25kg/m2 or higher
- High-fat dietary patterns as defined by Food Habits Questionnaire (FHQ) score of 2.5 or higher.
Mental or physical limitations that would preclude participation in group activities and discussion.
Recruitment
- Referrals from rural SC primary care physicians at three practice sites, followed by telephone interview from a research assistant (RA)
- All participants received $15 for attendance, Soul Food Light sweatshirts, small token gifts and door prizes at each intervention or testing session and results of their laboratory tests.
Design
- Participants randomly assigned to experimental or control groups by a computer-generated table of random numbers
- 48 to 49 participants were recruited every six months for a year to maintain small group size.
Blinding Used
RA blinded to group assignment.
Intervention
A culturally competent behavioral intervention targeting high-risk persons with diabetes utilizing:
- Educational classes in low-fat dietary strategies: Four weekly 1 1/2-hour classes focusing on planning, purchasing and preparing healthy low-fat meals and making healthy eating choices away from home
- Peer-professional group discussions:
- Four monthly one-hour discussion groups with a peer-professional that focused on group education and peer discussion
- Nurse case manager certified as a diabetes educator led group discussion and answered questions
- Follow-up by a nurse case manager: Weekly telephone follow-up used for additional educational support, early identification of complications, problem solving and help in making informed choices.
Control Group
Received referrals to a local eight-hour traditional diabetes class.
Statistical Analysis
- Multiple analysis of covariance (MANCOVA) used to evaluate effects of intervention from baseline to post-intervention
- Repeated measures analysis of covariance used to account for medications that changed over time.
Timing of Measurements
- Baseline
- Six months post-intervention.
Dependent Variables
- Physiological outcomes
- Hemoglobin A1C
- Lipids
- BMI
- Dietary behaviors
- Assessed using the FHQ adapted for southern African Americans
- Total scale scores greater than 2.5 indicate high-fat good habits.
Independent Variables
Culturally competent dietary self management behavioral intervention.
Control Variables
- Medical history
- Medications and treatment
- Diabetes education
- Exercise.
- Initial N: 97 agreed to participate and were confirmed for eligibility; 49 in treatment group, 48 in control group
- Attrition (final N): 65 participants retained throughout study, 67% retention rate; 38 in treatment group, 27 control group
- Age:
- Treatment group: 58.9 years mean age
- Control group: 55.7 years mean age
- Youngest 32 years, oldest 86 years.
- Ethnicity: African American from rural SC
- Other relevant demographics:
- Majority were women, unmarried, unemployed and in their late 50s
- Fewer than half had completed high school
- Mean A1C for entire sample: 7.8% (SD = 2.2)
- Majority were obese and reported high-fat food habits
- Half had elevated total cholesterol, LDL cholesterol and reported one or more other chronic disease
- Differences between groups at baseline:
- Duration of diabetes
- Treatment group: 10.4 years (SD = 7.9)
- Control group: 6.4 years (SD = 5.9)
- Retention in treatment group: 78% vs. retention in control group = 56%
- Duration of diabetes
- Location: Rural South Carolina.
Key Findings
Variables | Treatment Group | Control Group |
Measures and Confidence Intervals | Measures and Confidence Intervals | |
Body Mass Index | ||
Baseline |
35.39±8.1 |
35.75±8.8 |
Six months post-intervention | 35.58±8.0 | 36.32±8.5 |
Statistical significance of group difference | P=0.009 | |
Food Habits Questionnaire | ||
Baseline | 2.8±0.4 | 2.7±0.5 |
Six months post-intervention |
2.5±0.4 |
2.6±0.4 |
Statistical significance of group difference | P=0.005 |
Other Findings
- Men significantly increased in BMI by 2kg/m2 at six months compared to women at 0.16kg/mm2
- At six months, weight decreased a mean of 1.8kg for the treatment group and increased a mean 1.9kg for the control group
- Treatment group lowered high-fat dietary behaviors to a moderate level while the control group continued high-fat dietary behaviors
- Women lost 1.5 lbs while men gained 5.4 lbs; men gained weight even though they decreased their dietary fat behaviors significantly more than women did.
- The results of this study imply an 8% reduction in risks of diabetes complications and a 6% reduction in diabetes-related deaths
- Results suggest that programs like Soul Food Light can produce significant differences in weight and dietary behaviors in vulnerable African American populations.
Government: | National Institute of Nursing Research |
- Unsure how N was found in Table 1, cannot reproduce percentage for control group
- 69% of participants attended at least half of the eight intervention sessions, mean attendance was 4.8 sessions. Analysis included all participants regardless of attendance.
- Numbers in text do not match numbers in Table 2
- Tables 1 and 2 describing results are unclear as to how numbers were produced; text and tables do not match up
- Low retention rate in study with more dropouts in the control group, no explanation or details given. Results should take this into consideration.
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? | 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? | No | |
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? | No | |
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")? | ??? | |
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? | Yes | |
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? | Yes | |
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.) | ??? | |
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? | ??? | |
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? | Yes | |
6.6. | Were extra or unplanned treatments described? | Yes | |
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? | N/A | |
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? | No | |
8.2. | Were correct statistical tests used and assumptions of test not violated? | ??? | |
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)? | 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 | |