MNT: Weight Management (2015)
- Older than 18 years of age
- Body mass index (BMI) 25kg/m2 to 35kg/m2
- Diagnosed with Stage I to IIIa breast cancer within the past five years
- Completion of adjuvant treatment (chemotherapy or radiation) for at least three months
- Able to fill out questionnaires in English
- Provided informed consent.
- Plans to join another organized weight loss program
- Self-reported over 150 minutes per week of moderate to vigorous physical activity over past six months
- Uncontrolled diabetes
- Contraindications for treadmill testing or entry into a diet or exercise program.
Recruited from the British Columbia Cancer Agency by referral from their oncologist, word of mouth and poster advertising.
- The study used an experimental pre-post test, single group design to assess the feasibility of the intervention
- Participants completed a 24-week group-based intervention that consisted of a combined reduced-energy diet and exercise intervention
- Study outcome measures were completed at baseline, at 24 weeks and 36 weeks and included anthropometrics, body composition, dietary intake, physical activity and blood biomarkers.
- Instructed by an experienced Registered Dietitian (RD) and included 16 group-based sessions following the DPP curriculum with modifications
- Participants attended one group dietary session per week for the first eight weeks, followed by bi-weekly group sessions during Weeks Nine through 24
- Women were instructed to follow an individually prescribed reduction in energy intake according to their weight loss goal of loss of 7% of baseline body weight and a dietary fat intake of less than 20% of total energy intake
- Strategies to reduce energy intake were provided and success was monitored weekly with diet records and body weight.
The exercise intervention format was modified substantially from the DPP program to include two supervised 45-minute exercise sessions per week for 24 weeks at a dedicated research fitness facility, to achieve a total of 150 minutes per week of moderate to vigorous aerobic exercise.
- Descriptive statistics reported as means and standard deviations
- Changes in outcomes variables from baseline to 24 weeks were analyzed using a paired samples T-test
- Repeated measures analysis of variance was used to assess variables at the 36-week follow-up
- Independent samples T-tests were performed to compare differences in demographic factors and measures of adherence between participants who met the weight loss goal of 7% and those who did not achieve the goal at 24 weeks
- Sample size was calculated using the amount of expected weight loss equaling 7% and 12 participants were needed to detect 7% weight loss (80% power; alpha level, 0.05)
- P<0.05 was considered significant.
Timing of Measurements
- Measured at baseline
- Demographic information collected from electronic medical charts
- Measured at baseline and 24 weeks
- Dietary intake (energy intake, fat intake, energy from fat and percentage of energy from fat) assessed by a three-day diet record using Food Processor analysis software
- Body composition (total fat mass, lean body mass and percentage body fat) measured using dual energy X-ray absorptiometry
- Quality of life measured using the Functional Assessment of Cancer Therapy-Breast.
- Measured at baseline, end of study (24 weeks) and at follow-up (36 weeks)
- Anthropometrics (body weight, body mass index, waist and hip circumference) with all anthropometric measurements taken twice with the average being recorded
- Physical activity (VO2 max, metabolic equivalent hours per week) with VO2max measured by a maximal graded treadmill test with collection of expired gases
- Blood biomarkers [total cholesterol, triglycerides, high density lipoprotein cholesterol, low density lipoprotein cholesterol, C-reactive protein (CRP), c-peptide, glucose and insulin levels)].
- At 24 weeks, patients rated the program using a five-point scale on usefulness for weight loss, clarity of study materials and whether ongoing lifestyle change was likely following study.
- Dietary intake (energy intake, fat intake, energy from fat and percentage energy from fat)
- Body composition (total fat mass, lean body mass and body fat percentage)
- Quality of life
- Anthropometrics (body weight, body mass index, waist and hip circumference)
- Physical activity (VO2max, metabolic equivalent hours per week)
- Blood biomarkers [total cholesterol, triglycerides, high density lipoprotein cholesterol, low density lipoprotein cholesterol, C-reactive protein (CRP), c-peptide, glucose and insulin levels]
- Rating of program.
Independent VariablesDiet and exercise program.
- Demographic information
- Menopause status
- Cancer stage
- Treatment type
- Time since completion of treatment
- Current medications
- Attendance at interventions.
- Initial N: 14 females
- Attrition (final N): 14 females
- Age: 54.6±8.3 years
- Ethnicity: Not described
- Other relevant demographics: Overall, participants were obese, post-menopausal, receiving anti-hormonal therapy and had completed adjuvant cancer treatment approximately two years prior
- Anthropometrics: Baseline BMI, 30.1±3.6kg/m2
- Location: Canada.
- Baseline to end of intervention at 24 weeks
- Participants experienced a significant weight loss (3.8±5.0kg, P=0.01) and decreases in BMI (1.4±1.9kg/m2, P=0.01), waist circumference (4.2±6.6cm,P<0.03) and hip circumference (5.5±5.3cm, P<0.01)
- Total fat mass (-3.3±53.7kg, P<0.01), body fat percentage (-2.4±2.7%, P<0.01) and lean body mass (-0.6±1.9kg, P<0.001) decreased during the intervention.
- At 36-week follow-up
- At 36 weeks, the group lost an additional 0.8±1.2kg (P=0.03) and decreased their waist circumference an additional 2.9±4.0cm (P=0.02)
- At follow-up, participants had lost a total of 6% of baseline body weight, ranging +2.6% to -18.9%
- Exploratory analysis revealed participants who lost more than 7% of body weight were older (61±6.9 years vs. 51.1±7 years, P=0.03), attended a greater percentage of diet sessions (90.7±6.0% vs. 54.1±12.7%, P<0.001) and a greater percentage of supervised exercise sessions (87±6.9% vs. 54.9% vs. 17.9%, P=0.001).
- No significant changes in energy intake from baseline to end of study based on food records, however a trend toward a decreased percentage of energy from fat (P=0.09) and total grams of fat (P=0.1)
- Aerobic fitness increased by 11% from baseline to end of study (+0.2L per minute, P<0.001)
- Usual physical activity levels increased by 13.1±12.3 metabolic equivalent hours per week (P<0.01) at 24 weeks and had not changed significantly when re-assessed at 36 weeks (29.4±11.5 metabolic equivalent hours per week and 37.6±21.1 metabolic equivalent hours per week, respectively, P=0.12)
- Quality of life score improved at 24 weeks (9.6±9.9, P<0.01) and continued to improve at 36 weeks (P<0.01)
- 85% of participants rated the program as useful in helping them to lose weight and 100% would recommend it to a friend
- Program materials were reported to be useful (85%) and clear (77%) and 92% believed that they were likely to continue with lifestyle changes after the conclusion of study.
Other FindingsParticipants attended a mean of 1.3 supervised exercise sessions per week (67%) and 10 of the 16 group diet sessions (67%).
- The pilot study demonstrated the feasibility and preliminary efficacy of a lifestyle intervention program in breast cancer survivors with overweight and obesity delivered in a similar setting to an outpatient cancer center
- Using a modified DPP weight loss intervention, clinically significant improvements were demonstrated for body weight and aerobic fitness with modest improvements in body composition.
|Government:||Canadian Institute for Health Research|
- Small sample size
- Lack of control group
- Combination of pre and post-menopausal women
- Food records limited in detail leading to difficulty assessing intake.
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?||Yes|
|3.||Were study groups comparable?||N/A|
|3.1.||Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)||N/A|
|3.2.||Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?||N/A|
|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?||Yes|
|6.1.||In RCT or other intervention trial, were protocols described for all regimens studied?||N/A|
|6.2.||In observational study, were interventions, study settings, and clinicians/provider described?||Yes|
|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?||No|
|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?||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?||Yes|
|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?||Yes|
|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)?||Yes|
|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?||Yes|
|8.7.||If negative findings, was a power calculation reported to address type 2 error?||N/A|
|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|