In 2009, the American College of Sports Medicine convened an expert roundtable to issue guidelines on exercise for cancer survivors. This multidisciplinary group evaluated the strength of the evidence for the safety and benefits of exercise as a therapeutic intervention for survivors. The panel concluded that exercise is safe and offers myriad benefits for survivors including improvements in physical function, strength, fatigue, quality of life (QOL), and possibly recurrence and survival. Recommendations for situations in which deviations from the US Physical Activity Guidelines for Americans are appropriate were provided. Here, we outline a process for implementing the guidelines in clinical practice, and provide recommendations for how the oncology care provider can interface with the exercise and physical therapy community.
exercise; physical therapy; survivorship; cancer; rehabilitation; health promotion
Most breast cancer survivors do not engage in regular physical activity. Our physical activity behavior change intervention for breast cancer survivors significantly improved physical activity and health outcomes post-intervention during a pilot, feasibility study. Testing in additional sites with a larger sample and longer follow-up is warranted to confirm program effectiveness short and longer term. Importantly, the pilot intervention resulted in changes in physical activity and social cognitive theory constructs, enhancing our potential for testing mechanisms mediating physical activity behavior change. Here, we report the rationale, design, and methods for a two-site, randomized controlled trial comparing the effects of the BEAT Cancer physical activity behavior change intervention to usual care on short and longer term physical activity adherence among breast cancer survivors. Secondary aims include examining social cognitive theory mechanisms of physical activity behavior change and health benefits of the intervention. Study recruitment goal is 256 breast cancer survivors with a history of ductal carcinoma in situ or Stage I, II, or IIIA disease who have completed primary cancer treatment. Outcome measures are obtained at baseline, 3 months (i.e., immediately post-intervention), 6 months, and 12 months and include physical activity, psychosocial factors, fatigue, sleep quality, lower extremity joint dysfunction, cardiorespiratory fitness, muscle strength, and waist-to-hip ratio. Confirming behavior change effectiveness, health effects, and underlying mechanisms of physical activity behavior change interventions will facilitate translation to community settings for improving the health and well-being of breast cancer survivors.
oncology; exercise; survivorship; predictors; adherence
Depression is a distressing side effect of cancer and its treatment. In the general population, exercise is an effective antidepressant.
We conducted a systematic review and meta-analysis to determine the antidepressant effect of exercise in cancer survivors.
In May, 2011, we searched MEDLINE, PsycInfo, EMBASE, CINAHL, CDSR, CENTRAL, AMED, Biosis Previews, and Sport Discus, and citations from relevant papers and reviews.
Study Eligibility Criteria
We included randomized controlled trials (RCTs) comparing exercise interventions to usual care in cancer survivors, utilizing a self-report inventory or clinician rating to assess depressive symptoms, and reporting symptoms pre- and post-intervention.
7,042 study titles were identified and screened, with 15 RCTs included.
Effect sizes (ES) were reported as mean change scores. The Q test was conducted to evaluate heterogeneity of ES. Potential moderator variables were evaluated with examination of scatter plots and Wilcoxon rank-sum or Kruskal-Wallis tests.
The overall ES, under a random effects model, was −0.22 (CI −0.43, −0.09, p = 0.04). Significant moderating variables (ps < .05) were exercise location, exercise supervision, and exercise duration.
Only one study identified depression as the primary endpoint.
Exercise has modest positive effects on depressive symptoms with larger effects for programs that were supervised or partially supervised, not performed at home, and at least 30 minutes in duration.
Our results complement other studies showing that exercise is associated with reduced pain and fatigue and with improvements in quality of life among cancer survivors.
physical activity; mental health; cancer survivorship
Markers of insulin resistance such as the adiponectin:leptin ratio (A:L) and the homeostasis model assessment ratio (HOMA-IR) are associated with obesity and hyperinsulinemia, both established risk factors for endometrial cancer, and may therefore be informative regarding endometrial cancer risk. This study investigated the association between endometrial cancer risk and markers of insulin resistance, namely adiponectin, leptin, the A:L ratio, insulin, fasting glucose, and the HOMA-IR. We analyzed data from 541 incident endometrial cancer cases and 961 frequency age-matched controls in a population-based case–control study in Alberta, Canada from 2002 to 2006. Participants completed interview-administered questionnaires were assessed for anthropometric measures, and provided 8-h fasting blood samples either pre- or postoperatively. Blood was analyzed for concentrations of leptin, adiponectin, and insulin by immunoassay, and fasting plasma glucose levels were determined by fluorimetric quantitative determination. Compared with the lowest quartile, the highest quartile of insulin and HOMA-IR was associated with 64% (95% confidence intervals (CI): 1.12–2.40) and 72% (95% CI: 1.17–2.53) increased risks of endometrial cancer, respectively, and the highest quartile of adiponectin was associated with a 45% (95% CI: 0.37–0.80) decreased risk after multivariable adjustments. Null associations were observed between fasting glucose, leptin and A:L, and endometrial cancer risk. This population-based study provides evidence for a role of insulin resistance in endometrial cancer etiology and may provide one possible pathway whereby obesity increases the risk of this common cancer. Interventions aimed at decreasing both obesity and insulin resistance may decrease endometrial cancer risk.
Limited research has examined the association between physical activity, health-related fitness, and disease outcomes in breast cancer survivors. Here, we present the rationale and design of the Alberta Moving Beyond Breast Cancer (AMBER) Study, a prospective cohort study designed specifically to examine the role of physical activity and health-related fitness in breast cancer survivorship from the time of diagnosis and for the balance of life. The AMBER Study will examine the role of physical activity and health-related fitness in facilitating treatment completion, alleviating treatment side effects, hastening recovery after treatments, improving long term quality of life, and reducing the risks of disease recurrence, other chronic diseases, and premature death.
The AMBER Study will enroll 1500 newly diagnosed, incident, stage I-IIIc breast cancer survivors in Alberta, Canada over a 5 year period. Assessments will be made at baseline (within 90 days of surgery), 1 year, and 3 years consisting of objective and self-reported measurements of physical activity, health-related fitness, blood collection, lymphedema, patient-reported outcomes, and determinants of physical activity. A final assessment at 5 years will measure patient-reported data only. The cohort members will be followed for an additional 5 years for disease outcomes.
The AMBER cohort will answer key questions related to physical activity and health-related fitness in breast cancer survivors including: (1) the independent and interactive associations of physical activity and health-related fitness with disease outcomes (e.g., recurrence, breast cancer-specific mortality, overall survival), treatment completion rates, symptoms and side effects (e.g., pain, lymphedema, fatigue, neuropathy), quality of life, and psychosocial functioning (e.g., anxiety, depression, self-esteem, happiness), (2) the determinants of physical activity and health-related fitness including demographic, medical, social cognitive, and environmental variables, (3) the mediators of any observed associations between physical activity, health-related fitness, and health outcomes including biological, functional, and psychosocial, and (4) the moderators of any observed associations including demographic, medical, and biological/disease factors. Taken together, these data will provide a comprehensive inquiry into the outcomes, determinants, mechanisms, and moderators of physical activity and health-related fitness in breast cancer survivors.
Breast cancer; Exercise; Physical activity; Cardiorespiratory fitness; Muscular strength; Lymphedema; Quality of life; Exercise determinants; Recurrence; Survival
Over half of kidney cancer survivors (KCS) are completely inactive and only a quarter are meeting physical activity (PA) guidelines. This highlights the need to identify and understand the determinants of PA in this understudied population. The purpose of this study is to determine the social cognitive correlates of PA intention and behavior in KCS using the Theory of Planned Behavior (TPB).
All 1,985 KCS diagnosed between 1996 and 2010 in Alberta, Canada were mailed a self-report survey that consisted of the Godin Leisure Time Exercise Questionnaire and standard TPB items for intention, planning, perceived behavioral control (PBC), affective and instrumental attitudes, and descriptive and injunctive norms. Standard demographic and medical variables were also collected.
Completed surveys were received from 703 of 1,654 (43%) eligible KCS. The TPB was tested using structural equation modelling and demonstrated an adequate-to-good fit to the data [χ² = 256.88, p < .001; TLI = 0.97; CFI = 0.98; RMSEA = 0.06, 90% CI = 0.05-0.06].
There were significant pathways to PA from PBC (ß = 0.18, p = 0.02), planning (ß = 0.22, p < 0.01), and intention (ß = 0.31, p < 0.01); and to planning from intention (ß = 0.81, p < 0.01). In addition, there were significant model pathways to intention from instrumental attitude (ß = 0.28, p = 0.03), descriptive norm (ß = 0.09, p = 0.01), and PBC (ß = 0.52, p < 0.01). Overall, the TPB accounted for 69%, 63%, and 42% of the variance in intention, planning and PA, respectively.
The TPB appears to be a useful model for explaining PA in KCS. All TPB constructs except injunctive norm and affective attitude were useful for explaining intention with PBC emerging as the largest correlate. Developing PA interventions based on the TPB may be effective in promoting PA in KCS and may lead to important improvements in health.
Exercise; Motivation; Social cognitive models; Correlates
Studies indicate that strength training has beneficial effects on clinical health outcomes in prostate cancer patients during androgen deprivation therapy. However, randomized controlled trials are needed to scientifically determine the effectiveness of strength training on the muscle cell level. Furthermore, close examination of the feasibility of a high-load strength training program is warranted. The Physical Exercise and Prostate Cancer (PEPC) trial is designed to determine the effectiveness of strength training on clinical and muscle cellular outcomes in non-metastatic prostate cancer patients after high-dose radiotherapy and during ongoing androgen deprivation therapy.
Patients receiving androgen deprivation therapy for 9-36 months combined with external high-dose radiotherapy for locally advanced prostate cancer are randomized to an exercise intervention group that receives a 16 week high-load strength training program or a control group that is encouraged to maintain their habitual activity level. In both arms, androgen deprivation therapy is continued until the end of the intervention period.
Clinical outcomes are body composition (lean body mass, bone mineral density and fat mass) measured by Dual-energy X-ray Absorptiometry, serological outcomes, physical functioning (muscle strength and cardio-respiratory fitness) assessed with physical tests and psycho-social functioning (mental health, fatigue and health-related quality of life) assessed by questionnaires. Muscle cellular outcomes are a) muscle fiber size b) regulators of muscle fiber size (number of myonuclei per muscle fiber, number of satellite cells per muscle fiber, number of satellite cells and myonuclei positive for androgen receptors and proteins involved in muscle protein degradation and muscle hypertrophy) and c) regulators of muscle fiber function such as proteins involved in cellular stress and mitochondrial function. Muscle cellular outcomes are measured on muscle cross sections and muscle homogenate from muscle biopsies obtained from muscle vastus lateralis.
The findings from the PEPC trial will provide new knowledge on the effects of high-load strength training on clinical and muscle cellular outcomes in prostate cancer patients during androgen deprivation therapy.
Strength training; Prostate cancer; Androgen deprivation therapy; Clinical and muscle cellular outcomes
Our study aims were to describe physical activity patterns and associations with fatigue and depressive symptoms among rural breast cancer survivors.
Population-based, mailed survey of 483 rural breast cancer survivors including the International Physical Activity Questionnaire (IPAQ).
With regard to type and intensity, domestic/gardening and moderate intensity accounted for the largest percentage of total energy expenditure (i.e., 60% and 69%, respectively). MET-mins/week variables were categorized as 0, > 0 to < 500, and ≥ 500 to reflect sedentary, insufficient, and meets current public health recommendations. After adjustment, fatigue was significantly associated with domestic/gardening (mean fatigue for sedentary, insufficient, and meets recommendations were 18.9, 16.4, and 13.4, respectively; p=.0019), leisure activity (means were 16.0, 14.5, and 11.8, respectively; p=.047), moderate intensity (means were 18.4, 16.7, and 13.7, respectively; p=.011), and daily minutes sitting (means for ≤ 120 min, > 120 to ≤ 360 min, and > 360 min of sitting were 12.5, 14.2, and 17.2, respectively; p=.0029). Fatigue was not associated with occupational, transportation, walking, or vigorous activity. After adjustment, only leisure activity was associated with depressive symptoms (means for sedentary, insufficient, and meets recommendations were 7.8, 7.7, and 6.2, respectively; p=.039).
Physical activity measurement tools that do not include domestic/gardening activities may underestimate physical activity in rural breast cancer populations. Physical activity associations with fatigue and depressive symptoms differed based on physical activity type and intensity suggesting hypotheses related to exercise effects on fatigue and depressive symptoms.
Exercise; Oncology; Correlate; Predictor; Depression
Despite the known health benefits of physical activity, participation rates in cancer survivor groups remain low. Researchers have attempted to identify alternative modes of nontraditional physical activities that may increase participation and adherence rates. This study investigated the determinants of yoga in breast cancer survivors.
To examine predictors of Iyengar yoga adherence in breast cancer survivors using the theory of planned behaviour. Settings and Design: Classes were held either in Campus Recreation facilities or at the Behavioral Medicine Fitness Center at the University of Alberta in Edmonton, Canada. The study was an evaluation of an existing yoga program.
Materials and Methods:
Twenty-three post adjuvant therapy breast cancer survivors participating in a community-based, twice weekly, 12 week Iyengar yoga program were asked to complete baseline measures of the theory of planned behavior, demographic, medical, health/fitness, and psychosocial variables. Adherence was measured by objective attendance to the classes.
We analyzed univariate associations between predictors and yoga adherence with independent t-tests.
Adherence to the Iyengar yoga program was 63.9% and was predicted by stronger intention (P<0.001), greater self-efficacy (P=0.003), more positive instrumental attitude (Ps=0.025), higher disease stage (P=0.018), yoga experience in the past year, (P=0.044), diagnosis of a second cancer (P=0.008), lower fatigue (P=0.037), and greater happiness (P=0.023).
Adherence to Iyengar yoga in breast cancer survivors was strongly related to motivational variables from the theory of planned behaviour. Researchers attempting to improve yoga adherence in breast cancer survivors may benefit from targeting the key constructs in the theory of planned behaviour.
Iyengar yoga; breast cancer; survivorship; correlates; adherence; theory of planned behavior
Limited evidence exists on the determinants of quality of life (QoL) specific to adults with type 1 diabetes (T1D). Further, it appears no study has compared the determinants of QoL between T1D and type 2 diabetes (T2D) groups. The objectives of this study were to examine: (1) determinants of QoL in adults with T1D; and, (2) differences in QoL determinants between T1D and T2D groups.
The Alberta Longitudinal Exercise and Diabetes Research Advancement (ALEXANDRA) study, a longitudinal study of adults with diabetes in Alberta, Canada. Adults (18 years and older) with T1D (N = 490) and T2D (N = 1,147) provided information on demographics (gender, marital status, education, and annual income), personality (activity trait), medical factors (diabetes duration, insulin use, number of comorbidities, and body mass index), lifestyle behaviors (smoking habits, physical activity, and diet), health-related quality of life (HRQL) and life satisfaction. Multiple regression models identified determinants of HRQL and life satisfaction in adults with T1D. These determinants were compared with determinants for T2D adults reported in a previous study from this population data set. Factors significantly associated with HRQL and life satisfaction in either T1D or T2D groups were further tested for interaction with diabetes type.
In adults with T1D, higher activity trait (personality) score (β = 0.28, p < 0.01), fewer comorbidities (β = -0.27, p < 0.01), lower body mass index (BMI)(β = -0.12, p < 0.01), being a non-smoker (β = -0.14, p < 0.01), and higher physical activity levels (β = 0.16, p < 0.01) were associated with higher HRQL. Having a partner (β = 0.11, p < 0.05), high annual income (β = 0.16, p < 0.01), and high activity trait (personality) score (β = 0.27, p < 0.01) were significantly associated with higher life satisfaction. There was a significant age × diabetes type interaction for HRQL. The T2D group had a stronger positive relationship between advancing age and HRQL compared to the T1D group. No interaction was significant for life satisfaction.
Health services should target medical and lifestyle factors and provide support for T1D adults to increase their QoL. Additional social support for socioeconomically disadvantaged individuals living with this disease may be warranted. Health practitioners should also be aware that age has different effects on QoL between T1D and T2D adults.
quality of life; health-related quality of life; life satisfaction; type 1 diabetes; type 2 diabetes; adults with diabetes
Improving effectiveness of group exercise counseling for breast cancer survivors is needed.
Describe clinical observations, with research and translation implications, derived during group exercise counseling for breast cancer survivors.
While implementing group session components of an effective social cognitive theory-based exercise intervention, observations were made through verbal discussion with study staff, review of participant feedback, and prospective journaling by the group facilitator. The intervention has been implemented 11 times (i.e., 63 survivors; 66 group sessions). Thematic consistency, application to intervention goals and design, and implications were reconciled between two investigators.
Breast cancer diagnosis was a strong source of commonality among group participants. Participant age, time since diagnosis, and expectation for group sessions (e.g., group support versus health education) hindered group commonality. Barriers unique to the breast cancer experience were infrequent but people-pleasing behavior was often identified as a barrier to adherence. Feeling at risk for cancer recurrence was a major concern. Some participants required referral for mental health evaluation for pre-existing conditions (e.g., depression). Although participants easily understood time management, application of other behavioral modification techniques was more difficult.
A breast cancer diagnosis alone is not sufficient for commonality among group members. Teaching time management and positive reframing is essential. Protocols for appropriate mental health referrals are needed.
Implications for Practice
Our observations will assist group leaders in enhancing group dynamics and addressing obstacles hindering counseling effectiveness. Moreover, our results suggest hypotheses related to enhancing behavior change in a group setting worthy of future study.
oncology; physical activity; survivorship; social cognitive theory; health education
For decades, extensive research has explored the association between factors related to energy balance and the development of both colorectal cancer and prostate cancer. Physical inactivity, obesity, higher red meat consumption or Western pattern diet, insulin and insulin-like growth factors (IGFs) appear to increase the risk of colorectal cancer while obesity, high animal fat intake, insulin and IGFs have been associated with increasing prostate cancer risk and/or aggressiveness. Recently, there are growing observational data on the relationship between energetic host factors and progression of these cancers. While there are no large randomized trials in either colorectal cancer or prostate cancer assessing these factors on disease progression or disease-related mortality, the data supporting associations between some of these factors and colorectal or prostate cancer survivorship are getting more compelling. This article will evaluate the emerging data on energy balance in patients with colorectal or prostate cancer.
To better understand mechanisms of physical activity (PA) behavior change in breast cancer survivors, we examined mediation of a successful PA behavior change intervention by social cognitive theory (SCT) constructs. Our exploratory study randomized 41 breast cancer survivors to receive the 3-month intervention (INT) or usual care (UC). We used the Freedman and Schatzkin approach to examine mediation of intervention effect on PA 3 months postintervention by changes in SCT constructs from baseline to immediately postintervention. Compared with UC, the INT group reported lower barriers interference (mean difference = −7.8, 95% CI [−15.1, −0.4], d = −0.67, p = .04) and greater PA enjoyment (mean difference = 0.7, 95% CI [0, 1.5], d = 0.61, p = .06). Barriers interference mediated 39% (p = .004) of the intervention effect on PA 3 months postintervention. PA enjoyment was not a significant mediator. Reducing barriers to PA partially explained our intervention effect.
oncology; exercise; social cognitive theory; predictor; breast cancer; survivorship
To identify factors that mediate or moderate the effects of exercise on postmenopausal sex hormone concentrations.
Postmenopausal women were randomized to 12 months of aerobic exercise for 200 min/week (n = 160) or to a control group (n = 160). Intention-to-treat analyses were performed using general linear models with sex hormone concentrations at 6 and 12 months as the outcome. Mediation by adiposity and insulin was investigated by examining changes in effect estimates after adjustment for changes in these factors over 12 months. Moderation was studied as the interaction between group assignment and eight baseline characteristics.
Intervention effects on sex hormone–binding globulin (SHBG) and estradiol changes were attenuated with adjustment for change in overall body fat, while there was less attenuation adjusting for intra-abdominal fat change. Intervention effects on SHBG levels were unaffected by adjustment for insulin change. Significant interactions were identified between treatment and physical fitness (for SHBG and testosterone) and age (for testosterone), implying subgroup differences in intervention effect.
Our data suggest that overall fat loss partially mediated exercise-induced changes in estradiol and SHBG concentrations. No previous RCT in postmenopausal women has studied moderators of exercise-induced sex hormone changes; therefore, future studies are needed to corroborate our results.
Exercise; Gonadal steroid hormones; Sex hormone–binding globulin; Randomized controlled trial; Breast neoplasms
Despite evidence that physical activity improves the health and well-being of prostate cancer survivors, many men do not engage in sufficient levels of activity. The primary aim of this study (ENGAGE) is to determine the efficacy of a referral and physical activity program among survivors of prostate cancer, in terms of increasing participation in physical activity. Secondary aims are to determine the effects of the physical activity program on psychological well-being, quality of life and objective physical functioning. The influence of individual and environmental mediators on participation in physical activity will also be determined.
This study is a cluster randomised controlled trial. Clinicians of prostate cancer survivors will be randomised into either the intervention or control condition. Clinicians in the intervention condition will refer eligible patients (n = 110) to participate in an exercise program, comprising 12 weeks of supervised exercise sessions and unsupervised physical activity. Clinicians allocated to the control condition will provide usual care to eligible patients (n = 110), which does not involve the recommendation of the physical activity program. Participants will be assessed at baseline, 12 weeks, 6 months, and 12 months on physical activity, quality of life, anxiety, depression, self-efficacy, outcome expectations, goals, and socio-structural factors.
The findings of this study have implications for clinicians and patients with different cancer types or other chronic health conditions. It will contribute to our understanding on the potential impact of clinicians promoting physical activity to patients and the long term health benefits of participating in physical activity programs.
Australia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12610000609055
Deakin University Human Research Ethics Approval 2011-085
Physical activity is a known modifiable lifestyle means for reducing postmenopausal breast cancer risk, but the biologic mechanisms are not well understood. Metabolic factors may be involved. In this study, we aimed to determine the effects of exercise on insulin resistance (IR) indicators, IGF1, and adipokines in postmenopausal women. The Alberta Physical Activity and Breast Cancer Prevention Trial was a two-armed randomized controlled trial in postmenopausal, inactive, cancer-free women. A year-long aerobic exercise intervention of 225 min/week (n=160) was compared with a control group asked to maintain usual activity levels (n=160). Baseline, 6- and 12-month serum levels of insulin, glucose, IGF1, IGF-binding protein 3 (IGFBP3), adiponectin, and leptin were assayed, and after data collection, homeostasis model assessment of IR (HOMA-IR) scores were calculated. Intention-to-treat analyses were performed using linear mixed models. The treatment effect ratio (TER) of exercisers to controls was calculated. Data were available on 308 (96.3%) women at 6 months and 310 (96.9%) women at 12 months. Across the study period, statistically significant reductions in insulin (TER=0.87, 95% confidence interval (95% CI)=0.81–0.93), HOMA-IR (TER=0.86, 95% CI=0.80–0.93), and leptin (TER=0.82, 95% CI=0.78–0.87), and an increase in the adiponectin/leptin ratio (TER=1.21, 95% CI=1.13–1.28) were observed in the exercise group compared with the control group. No significant differences were observed for glucose, IGF1, IGFBP3, adiponectin or the IGF1/IGFBP3 ratio. Previously inactive postmenopausal women who engaged in a moderate-to-vigorous intensity exercise program experienced changes in insulin, HOMA-IR, leptin, and adiponectin/leptin that might decrease the risk for postmenopausal breast cancer.
The Alberta Physical Activity and Breast Cancer Prevention (ALPHA) Trial examined the influence of aerobic exercise on biologic factors that are associated with breast cancer risk. Mammographic density, a secondary outcome, is reported here.
The ALPHA Trial was a parallel group randomized controlled trial conducted between May 2003 and July 2007. Postmenopausal, sedentary women aged 50 to 74 years (n = 320) were evenly randomized to aerobic exercise (45 minutes, 5 days per week) or control (usual lifestyle) for one year. Dense fibroglandular tissue and nondense fatty tissue were measured from mammograms at baseline and one year using computer-assisted thresholding software for area measurements and a new technique that relies on the calibration of mammography units with a tissue-equivalent phantom for volumetric measurements.
Nondense volume decreased in the exercise group relative to the control group (difference between groups = −38.5 cm3; 95% confidence interval = −61.6 to 15.4; P = 0.001). Changes in total body fat accounted for this decrease. Changes in dense area and dense volume, measures that have previously been associated with breast cancer risk, were not significantly different between the groups (P ≥ 0.36).
To achieve changes in mammographic measures may require more exercise or a study population with higher baseline levels of sex hormones or a wider range of mammographic density. The data from this study, however, suggest that the protective effect of exercise on breast cancer risk may operate through a mechanism other than mammographic density.
Physical activity; mammographic density; breast cancer; postmenopausal women; randomized controlled trial
We examined how an aerobic exercise intervention influenced circulating estradiol, estrone, sex hormone–binding globulin (SHBG), androstenedione, and testosterone levels, which may be involved in the association between physical activity and breast cancer risk.
A two-center, two-arm randomized controlled trial of exercise was conducted in 320 postmenopausal, sedentary women age 50 to 74 years. Participants were randomly assigned to a 1-year aerobic exercise intervention of 225 min/wk (n = 160) or to a control group who maintained their usual level of activity (n = 160). Baseline, 6-month, and 12-month assessments of estrone, estradiol, androstenedione, and testosterone were quantified by radioimmunoassay after extraction, and SHBG was quantified by an immunometric assay. Intent-to-treat analyses were performed using linear mixed models.
Blood data were available on 309 women (96.6%) at 12 months. Women in the intervention group exercised an average of 3.6 d/wk for 178 min/wk. At 12 months, statistically significant reductions in estradiol (treatment effect ratio [TER] = 0.93; 95% CI, 0.88 to 0.98) and free estradiol (TER = 0.91; 95% CI, 0.87 to 0.96) and increases in SHBG (TER = 1.04; 95% CI, 1.02 to 1.07) were observed in the exercise group compared with the control group. No significant differences in estrone, androstenedione, and testosterone levels were observed between exercisers and controls at 12 months.
This trial found that previously sedentary postmenopausal women can adhere to a moderate- to vigorous-intensity exercise program that results in changes in estradiol and SHBG concentrations that are consistent with a lower risk for postmenopausal breast cancer.
To examine the role of self-efficacy and depression as potential pathways from physical activity to fatigue in two study samples: breast cancer survivors (BCS; N=192) and individuals with multiple sclerosis (MS; N=292).
We hypothesized that physical activity would be indirectly associated with fatigue through its influence on self-efficacy and depressive symptomatology. A cross-sectional path analysis (BCS) and a longitudinal panel model (MS) were conducted within a covariance modeling framework.
Physical activity had a direct effect on self-efficacy, and in turn, self-efficacy had both a direct effect on fatigue and an indirect effect through depressive symptomatology in both samples. In the MS sample, physical activity also had a direct effect on fatigue. All model fit indices were excellent. These associations remained significant when controlling for demographics and health status indicators.
Our findings suggest support for at least one set of psychosocial pathways from physical activity to fatigue, an important concern in chronic disease. Subsequent work might replicate such associations in other diseased populations and attempt to determine whether model relations change with physical activity interventions, and the extent to which other known correlates of fatigue such as impaired sleep and inflammation can be incorporated into this model.
Breast Cancer; Multiple Sclerosis; Self-Efficacy; Physical Activity; Depression; Fatigue
The widespread incorporation of behavioral support interventions into exercise trials has sometimes caused confusion concerning the primary purpose of a trial. The purpose of the present paper is to offer some conceptual and methodological distinctions among three types of exercise trials with a view towards improving their design, conduct, reporting, and interpretation.
Exercise trials can be divided into "health outcome trials" or "behavior change trials" based on their primary outcome. Health outcome trials can be further divided into efficacy and effectiveness trials based on their potential for dissemination into practice. Exercise efficacy trials may achieve high levels of exercise adherence by supervising the exercise over a short intervention period ("traditional" exercise efficacy trials) or by the adoption of an extensive behavioral support intervention designed to accommodate unsupervised exercise and/or an extended intervention period ("contemporary" exercise efficacy trials). Exercise effectiveness trials may emanate from the desire to test exercise interventions with proven efficacy ("traditional" exercise effectiveness trials) or the desire to test behavioral support interventions with proven feasibility ("contemporary" exercise effectiveness trials). Efficacy, effectiveness, and behavior change trials often differ in terms of their primary and secondary outcomes, theoretical models adopted, selection of participants, nature of the exercise and comparison interventions, nature of the behavioral support intervention, sample size calculation, and interpretation of trial results.
Exercise researchers are encouraged to clarify the primary purpose of their trial to facilitate its design, conduct, and interpretation.
Physical activity is an important component in promoting a healthy life style in cancer survivors. We estimated the proportion of cancer survivors who are physically active, defined as meeting public health exercise guidelines, and changes in level of physical activity (LPA) from before diagnosis to after treatment. We also identified medical and demographic factors associated with LPA and its changes.
A cross-sectional survey assessing LPA before diagnosis and after treatment, together with demographic and medical variables in 975 cancer survivors.
Forty-five percent of the cancer survivors were physically active after treatment. Before diagnosis and after treatment 33% were active, whereas 40% were inactive at both time points. Fifteen percent were active before diagnosis but inactive after treatment, and 12% were inactive before diagnosis but active after treatment. Increasing age and weight, low education, comorbidity and smoking were associated with physical inactivity after treatment. Change in LPA from active to inactive was associated with comorbidity, distant disease and smoking, while a change from inactive to active was associated with high education.
Less than half of cancer survivors were physically active. Almost three quarters of cancer survivors remained stable in LPA. The remaining quarter changed LPA, with slightly more cancer survivors becoming inactive than active. Age, weight, education, comorbidity, disease stage and smoking can identify survivors at risk of physical inactivity after treatment.
Implications for cancer survivors
Recognizable variables can be used to identify physically inactive cancer survivors after treatment and give these survivors support to start or maintain LPA.
Exercise guidelines; Physical activity change; Cancer survivors
Purpose: Strenuous upper-extremity activity and/or exercise have traditionally been prescribed for breast cancer survivors with or at risk of developing lymphedema. The purpose of this study was to assess the effect of an acute bout of exercise on upper-limb volume and symptoms in breast cancer survivors, with the intent to provide pilot data to guide a subsequent larger study.
Methods: Twenty-three women who regularly participated in dragon-boat racing took part in the study. A single exercise bout was performed at a moderate intensity (rating of perceived exertion: 13–14) for 20 continuous minutes on an arm ergometer. The difference between affected and unaffected limb volume was assessed pre- and post-exercise via measurements of limb circumference at five time points.
Results: Although limb volume increased following exercise in both limbs, the difference between the limbs remained stable at each measurement point. Only one participant was found to have an increase in arm-volume difference of >100 ml post intervention, and only four participants reported symptoms of tension and/or heaviness in the affected limb.
Conclusion: The results suggest that limb volume in breast cancer survivors increases after an acute bout of upper-limb exercise but that, for the majority of women, the response is not different between affected and unaffected limbs. Future research using a larger sample and more sensitive measurement methods are recommended.
arm; breast neoplasms; exercise; lymphedema; upper extremity; bras; exercise; lymphœdème; membres supérieurs; néoplasme; sein; tumeur
Attempts to demonstrate the efficacy of interventions aimed at increasing physical activity (PA) have been mixed. Further, studies are seldom designed in a manner that facilitates the understanding of how or why a treatment is effective or ineffective and PA intervention designs should be guided by a heavier reliance upon behavioral theory. The use of a mediating variable framework offers a systematic methodological approach to testing the role of theory, and could also identify the effectiveness of specific intervention components. The primary purpose of this paper was to test the mediating role that cognitive constructs may have played in regards to the positive effect that a workplace behavioral intervention had on leisure-time PA for women. A subsidiary purpose was to examine the cross-sectional relationships of these cognitive constructs with PA behavior.
The Physical Activity Workplace Study was a randomized controlled trial which compared the effects of stage-matched and standard print materials upon self-reported leisure-time PA, within a workplace sample at 6 and 12-months. In this secondary analysis we examined the mediation effects of 14 psychosocial constructs across 3 major social-cognitive theories which were operationalized for the intervention materials and measured at baseline, 6 and 12-months. We examined change in PA and change in the psychological constructs employing a mediation strategy proposed by Baron and Kenny for: (1) the first 6-months (i.e., initial change), (2) the second 6-months (i.e., delayed change), and (3) the entire 12-months (overall change) of the study on 323 women (n = 213 control/standard materials group; n = 110 stage-matched materials group).
Of the 14 constructs and 42 tests (including initial, delayed and overall change) two positive results were identified (i.e., overall change in pros, initial change in experiential powerful intervention approaches processes), with very small effect sizes. However, these mediating results were eliminated after adjusting for the multiple statistical tests.
The intervention did not change these mediators in any substantive way, and show a similar pattern to prior research where interventions generally do not result in a change in mediation of behavior change. It is important to report mediation results in randomized controlled trials whether the findings are null or positive. Future studies may wish to focus on more detailed dose-response issues between mediators and behavior, the inclusion of moderators that could affect individual change, or different mediator constructs at higher levels of measurement specificity. Continued work on innovative and more powerful PA intervention approaches are needed.
A population-based case–control study of physical activity and endometrial cancer risk was conducted in Alberta between 2002 and 2006. Incident, histologically confirmed cases of endometrial cancer (n = 542) were frequency age-matched to controls (n = 1,032). The Lifetime Total Physical Activity Questionnaire was used to measure occupational, household, and recreational activity levels. Multivariable logistic regression analyses were conducted. Total lifetime physical activity reduced endometrial cancer risk (odds ratio [OR] for >129 vs. <82 MET-h/week/year = 0.86, 95% confidence interval [95% CI]: 0.63, 1.18). By type of activity, the risks were significantly decreased for greater recreational activity (OR = 0.64, 95% CI: 0.47, 0.87), but not for household activity (OR = 1.09, 95% CI: 0.75, 1.58) and/or occupational activity (OR = 0.90, 95% CI: 0.67, 1.20) when comparing the highest to lowest quartiles. For activity performed at different biologically defined life periods, some indication of reduced risks with activity done between menarche and full-term pregnancy and after menarche was observed. When examining the activity by intensity of activity (i.e., light <3, moderate 3–6, and vigorous >6 METs), light activity slightly decreased endometrial cancer risk (OR = 0.68, 95% CI: 0.48, 0.97) but no association with moderate or vigorous intensity activity was found. Endometrial cancer risk was increased with sedentary occupational activity by 28% (95 CI%: 0.89, 1.83) for >11.3 h/week/year versus ≤2.4 h/week/year or by 11% for every 5 h/week/year spent in sedentary behavior. This study provides evidence for a decreased risk between lifetime physical activity and endometrial cancer risk and a possible increased risk associated with sedentary behavior.
Electronic supplementary material
The online version of this article (doi:10.1007/s10552-010-9538-1) contains supplementary material, which is available to authorized users.
Case–control study; Cancer etiology; Endometrial neoplasms; Physical activity; Risk factors
The primary aim of this study was to compare the efficacy of three physical activity (PA) behavioural intervention strategies in a sample of adults with type 2 diabetes.
Participants (N = 287) were randomly assigned to one of three groups consisting of the following intervention strategies: (1) standard printed PA educational materials provided by the Canadian Diabetes Association [i.e., Group 1/control group)]; (2) standard printed PA educational materials as in Group 1, pedometers, a log book and printed PA information matched to individuals' PA stage of readiness provided every 3 months (i.e., Group 2); and (3) PA telephone counseling protocol matched to PA stage of readiness and tailored to personal characteristics, in addition to the materials provided in Groups 1 and 2 (i.e., Group 3). PA behaviour measured by the Godin Leisure Time Exercise Questionnaire and related social-cognitive measures were assessed at baseline, 3, 6, 9, 12 and 18-months (i.e., 6-month follow-up). Clinical (biomarkers) and health-related quality of life assessments were conducted at baseline, 12-months, and 18-months. Linear Mixed Model (LMM) analyses will be used to examine time-dependent changes from baseline across study time points for Groups 2 and 3 relative to Group 1.
ADAPT will determine whether tailored but low-cost interventions can lead to sustainable increases in PA behaviours. The results may have implications for practitioners in designing and implementing theory-based physical activity promotion programs for this population.
Clinical Trials Registration
ClinicalTrials.gov identifier: NCT00221234