HD: Effectiveness of Nutrition Intervention Methods (2010)
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
This study, African-American Women Fight Cancer with Fitness, tested the efficacy of a culturally targeted nutrition and physical activity intervention.
- 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 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.
- 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.
- 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).
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.
Estimated dietary intake, as measured by the National Cancer Institute Health Habits and History Questionnaire.
Intervention: Fighting Cancer with Fitness.
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.
- 44.56 years was the mean age for intervention group
- 45.52 years was the mean age for control group.
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.
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.
Measures and confidence intervals
Measures and confidence intervals
Statistical Significance of Group Difference at 12-month Follow-up
Dietary fiber (g/day)
Carotenoids (alpha carotene+beta carotene+lutein+ zeathanxin) (ug)
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
|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|
|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|