HD: Effectiveness of Nutrition Intervention Methods (2010)
This study, African-American Women Fight Cancer with Fitness, tested the efficacy of a culturally targeted nutrition and physical activity intervention.
- Women
- Self-identified as African-American.
- 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).
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.
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.
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.
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).
- 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.
Government: | National Cancer Institute Research Award (R01 CA 73512), NCI Research Supplement for Underrepresented Minority Graduate Assistants |
- 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
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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? | 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 | |