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Health Disparities

HD: Effectiveness of Nutrition Intervention Methods (2010)

Citation:

McCarthy WJ, Yancey AK, Harrison GG, Leslie J, Siegel JM. Fighting Cancer with Fitness: dietary outcomes of a randomized, controlled lifestyle change intervention in healthy African-American women. Prev Med. 2007 Mar; 44(3): 246-253. Epub 2006 Dec 6.

PubMed ID: 17156835
 
Study Design:
Randomized Controlled Trial
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

This study, African-American Women Fight Cancer with Fitness, tested the efficacy of a culturally targeted nutrition and physical activity intervention. 

Inclusion Criteria:
  • Women
  • Self-identified as African-American.
Exclusion Criteria:
  • History of invasive carcinoma
  • Inability to walk one mile without assistance
  • Current cigarette smoking
  • Not living or working within a 10-mile radius of the intervention site
  • Inability to commit to participating in the study or follow-up assessments for two years
  • High level of previous use of structured weight-loss programs (three or more).
Description of Study Protocol:

Recruitment

  • Recruitment procedures and strategies were described in previous paper (Yances, Miles et al., 2001)
  • One-year gym membership offered an incentive for study participation for all subjects
  • Recruitment, pilot study and group sessions all at same black-owned commercial gym.

Design

  • Randomized trial, with an attention control condition
  • Intervention and control groups both received eight weekly two-hour sessions
  • Study consisted of six consecutive three-month periods for approximately 60 women at a time (30 intervention and 30 control)
  • Follow-up data collected at two months (post-intervention), six months and 12 months
  • Control group, Fighting Cancer through Knowledge, received sessions on African-American women's health topics:
    • Ethnic disparities in cancer incidence and outcomes were explored
    • Topics included tobacco control, screening behaviors for cancer, menopause and depression
    • Cancer prevention videos from the UCLA Division of Cancer Prevention and Control Research were featured.

Blinding and Randomization

  • Randomization to study group was based on enrollment number using a random number-generating computer algorithm
  • Staff member assigning subjects to groups was blinded to group identification and had no contact with study subjects
  • Subjects were blinded to which group was intervention group, fitness or education
  • Staff completing assessments were blinded to subject assignment at all time periods.

Intervention

  • Eight weekly 90-minute interactive group sessions, entitled Fighting Cancer with Fitness
  • Skills training in exercise regimen
    • Muscle strengthening
    • Flexibility enhancement
    • Aerobic conditioning.
  • Nutrition education
    • Low-fat, complex carbohydrate-rich (high-fiber) diet
    • Emphasized cancer-preventive benefits of increased fruit and vegetable intake.
  • Subjects provided dietitian with 24-hour food recall up to four times during eight-week period and were given feedback on quality and adequacy of intake
  • Social support: Each subject was encouraged to invite one close female to accompany her during post-intervention use of the gym (friend received free membership as well).

Statistical Analysis

Nutrient intake between groups were compared at baseline and 12 months using paired T-tests.

Data Collection Summary:

Timing of Measurements

  • Food frequency data collected at baseline and 12 months only
  • Sociodemographic data collected only at baseline
  • Other measures collected at baseline, two months, six months and 12 months
  • At all follow-up assessments subjects were paid $50 as an incentive.

Dependent Variables

Estimated dietary intake, as measured by the National Cancer Institute Health Habits and History Questionnaire.

Independent Variables

Intervention: Fighting Cancer with Fitness.

Control Variables

African-American women.

Description of Actual Data Sample:

Initial N

366 African American women

  • 188 intervention group
  • 178 control group.

Attrition (final N)

  • More than 70% (approximately 256 women) were retained at 12 months 
  • 201 African American women used for data analysis
    • Due to large amount of missing data
    • 55% retention rate for data analysis.

Age

Mid 40s

  • 44.56 years was the mean age for intervention group
  • 45.52 years was the mean age for control group.

Ethnicity

African-American.

Other relevant demographics

  • No differences in demographics noted between groups at baseline
  • Mean household income=$40K to $59K
  • Mean years of education=15 years
  • Mean height=1.66m
  • Mean BMI=30
  • Mean weight=82kg to 85kg 
  • Mean systolic blood pressure=122mmHg to 124mmHg
  • Mean diastolic blood pressure=74mmHg.

Location

None given.

Summary of Results:

Key Findings

Within group comparisons from baseline to 12 month follow-up:

  • Control group had significantly decreased reported energy (kcal/basal metabolic rate) intake from baseline (1.19±0.56) to 12-month follow-up (0.97±0.41), P<0.01
  • Both groups significantly reduced dietary intake from fat at 12-month follow-up
  • Treatment group increased fiber intake from baseline (14.4g per day) to 12-month follow-up (16.1g per day±7.3g per day), P<0.01
  • Both groups significantly increased carotenoid intake from baseline to 12-month follow-up.

Treatment group vs Control group at 12 months:

  • Treatment group had a significantly higher fiber intake compared with intake by the control group at 12 months
  • Treatment group had a significantly higher carotenoid intake compared with intake by the control group at 12 months.

Variables

Treatment Group

Measures and confidence intervals

Control Group

Measures and confidence intervals

Statistical Significance of Group Difference at 12-month Follow-up

Dietary fiber (g/day)

16.1±7.3 14.1±6.6

P<0.05

Carotenoids (alpha carotene+beta carotene+lutein+ zeathanxin) (ug)

13,140±1,217

11,355±779

P<0.05

Other Findings

Total fruit, juice and vegetable intake increased substantially for treatment group from baseline to follow up (30 servings per week vs. 39 servings per week).

 

Author Conclusion:
  • Seems dietary quality improvement is due to increased fruit and vegetable intake among intervention group women
  • Intervention group did not decrease dietary intake but improved the overall quality of their diet, which was consistent with the message provided by the Fitness group.
Funding Source:
Government: National Cancer Institute Research Award (R01 CA 73512), NCI Research Supplement for Underrepresented Minority Graduate Assistants
Reviewer Comments:
  • Study sample size misleading; 366 women used only for baseline demographic data
  • Actual “n” for data analysis was 201 comparing baseline to follow-up, 55% of sample
  • No information given for those records lost to follow-up in analysis. 
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? No
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) 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
  3.4. 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? Yes
  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? Yes
  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.) 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? No
  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? No
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? No
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? No
  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? 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? 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? No
  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? No
  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)? No
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? No
  8.6. Was clinical significance as well as statistical significance reported? No
  8.7. If negative findings, was a power calculation reported to address type 2 error? No
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