Health Disparities

HD: Effectiveness of Nutrition Intervention Methods (2010)


Anderson-Loftin W, Barnett S, Bunn P, Sullivan P, Hussey J, Tavakoli A. Soul food light: Culturally competent diabetes education. Diabetes Educ. 2005 Jul-Aug; 31(4): 555-563. 

PubMed ID: 16100331
Study Design:
Randomized Controlled Trial
A - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

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.

Inclusion Criteria:
  • 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.
Exclusion Criteria:

Mental or physical limitations that would preclude participation in group activities and discussion.

Description of Study Protocol:


  • 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.


  • 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.


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.
Data Collection Summary:

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.


Description of Actual Data Sample:
  • 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%
  • Location: Rural South Carolina.
Summary of Results:


Key Findings

Variables Treatment Group Control Group
  Measures and Confidence Intervals Measures and Confidence Intervals
Body Mass Index



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



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.


Author Conclusion:
  • 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.
Funding Source:
Government: National Institute of Nursing Research
Reviewer Comments:
  • 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
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