Kristina H. Karvinen

Alberta Physical Activity and Breast Cancer Prevention Trial: Sex Hormone Changes in a Year-Long Exercise Intervention Among Postmenopausal Women

PURPOSE 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. METHODS 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. RESULTS 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. CONCLUSION 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.

Changes in insulin resistance indicators, IGFs, and adipokines in a year-long trial of aerobic exercise in postmenopausal women

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.

Adiposity changes after a 1-year aerobic exercise intervention among postmenopausal women: a randomized controlled trial

Objective:We examined the effects of an aerobic exercise intervention on adiposity outcomes that may be involved in the association between physical activity and breast cancer risk.Design:This study was a two-centre, two-armed, randomized controlled trial. The 1-year-long exercise intervention included 45 min of moderate-to-vigorous aerobic exercise five times per week, with at least three of the sessions being facility based. The control group was asked not to change their activity and both groups were asked not to change their diet.Subjects:A total of 320 postmenopausal, sedentary, normal weight-to-obese women aged 50–74 years who were cancer-free, nondiabetic and nonhormone replacement therapy users were included in this study.Measurements:Anthropometric measurements of height, weight and waist and hip circumferences; dual energy X-ray absorptiometry measurements of total body fat; and computerized tomography measurements of abdominal adiposity were carried out.Results:Women in the exercise group exercised a mean of 3.6 days (s.d.=1.3) per week and 178.5 min (s.d.=76.1) per week. Changes in all measures of adiposity favored exercisers relative to controls (P<0.001). The mean difference between groups was: −1.8 kg for body weight; −2.0 kg for total body fat; −14.9 cm2 for intra-abdominal fat area; and −24.1 cm2 for subcutaneous abdominal fat area. A linear trend of greater body fat loss with increasing volume of exercise was also observed.Conclusion:A 1-year aerobic exercise program consistent with current public health guidelines resulted in reduced adiposity levels in previously sedentary postmenopausal women at higher risk of breast cancer.

Associations between Exercise and quality of life in Bladder Cancer survivors: A population-based study

Background: Exercise has been shown to improve quality of life (QoL) in some cancer survivor groups, but it is unknown if the unique QoL issues faced by bladder cancer survivors are also amenable to an exercise intervention. This study provides the first data examining the association between exercise and QoL in bladder cancer survivors. Methods: Bladder cancer survivors identified through a provincial cancer registry were mailed a survey that included the Godin Leisure Time Exercise Questionnaire, the Functional Assessment of Cancer Therapy-Bladder (FACT-Bl) scale, and the Fatigue Symptom Inventory. Results: Of the 525 bladder cancer survivors (51% response rate) that completed the survey, 22.3% were meeting public health exercise guidelines in the past month, 16.0% were insufficiently active (i.e., some exercise but less than the guidelines), and 61.7% were completely sedentary. ANOVA indicated a general linear association between meeting guidelines and QoL, with those meeting guidelines reporting more favorable scores than completely sedentary survivors on the FACT-Bl (mean difference, 7.6; 95% confidence interval, 3.6-11.7; P < 0.001), the FACT (P = 0.001), the trial outcome index (P < 0.001), functional well-being (P < 0.001), additional concerns (P = 0.001), sexual functioning (P < 0.001), erectile function (P < 0.001), body image (P < 0.001), and various fatigue indicators (P < 0.05). Adjusting for key medical and demographic factors slightly attenuated the magnitude of the associations but did not alter the substantive conclusions. Conclusions: Exercise is positively associated with QoL in bladder cancer survivors, although few are meeting public health exercise guidelines. Studies testing the causal effects of exercise on QoL issues unique to this population are warranted. (Cancer Epidemiol Biomarkers Prev 2007;16(5):984–90)

Exercise preferences of endometrial cancer survivors: a population-based study.

Exercise has gained recognition as an effective supportive care intervention for cancer survivors, yet participation rates are low. Knowledge of the specific exercise counseling and programming preferences of cancer survivors may be useful for designing effective interventions. In this study, we examined the exercise preferences of 386 endometrial cancer survivors. Participants completed a questionnaire that included measures of past exercise behavior, exercise preferences, and medical and demographic information. Some key findings were as follows: (a) 76.9% of participants said they were interested or might be interested in doing an exercise program and (b) 81.7% felt they were able or likely able to actually do an exercise program. Participants also indicated that walking was their preferred activity (68.6%) and moderate exercise was their preferred intensity (61.1%). Logistic regression analyses showed that meeting public health guidelines for exercise, being overweight or obese, receiving adjuvant treatment, months since diagnosis, income, marital status, and level of education all influenced exercise preferences. These results suggest that endometrial cancer survivors have unique exercise preferences that are moderated by a number of demographic and medical variables. These findings may have implications for the design and implementation of clinical and population-based exercise interventions for endometrial cancer survivors.

Exercise programming and counseling preferences in bladder cancer survivors: a population-based study.

IntroductionDespite growing evidence of the benefits of exercise in cancer survivors, exercise participation rates are low. Understanding the unique exercise programming and counseling preferences of different cancer survivor groups may facilitate the delivery of optimal exercise programs in these growing populations. To date, no study has examined these preferences in bladder cancer survivors.Materials and methodsParticipants were 397 bladder cancer survivors who completed a mailed survey in the province of Alberta, Canada.ResultsThe majority of survivors indicated they would be interested (81.1%) and able (84.3%) to participate in an exercise program designed for bladder cancer survivors. We also found strong preferences for home-based exercise programming (53.7%), walking (81.1%), moderate intensity activity (61.7%) and unsupervised sessions (70.6%). Logistic regression analyses showed that older survivors were more likely to prefer to exercise at home (77 vs. 68%; OR = 4.21, 95% CI = 0.188–0.962, p = 0.040), do light intensity exercise (33 vs. 16%; OR = 4.50, 95% CI = 0.208–0.940, p = 0.034) and want unsupervised exercise sessions (75 vs. 62%; OR = 4.60, 95% CI = 1.07–4.08, p = 0.032). Body mass index, age, adjuvant therapy, marital status, income and education also influenced some exercise preferences.ConclusionsThese findings suggest that bladder cancer survivors are interested in receiving exercise counseling and have some consistent programming preferences including exercising at home, walking, and moderate intensity exercise. Many preferences were modified by demographic and medical factors.Implications for cancer survivorsUnderstanding the unique exercise preferences of bladder cancer survivors may be used to inform the design and delivery of exercise programs in this growing population.

Multicomponent intervention to reduce daily sedentary time: a randomised controlled trial

Objectives To test the efficacy of a multicomponent technology intervention for reducing daily sedentary time and improving cardiometabolic disease risk among sedentary, overweight university employees. Design Blinded, randomised controlled trial. Setting A large south-eastern university in the USA. Participants 49 middle-aged, primarily female, sedentary and overweight adults working in sedentary jobs enrolled in the study. A total of 40 participants completed the study. Interventions Participants were randomised to either: (1) an intervention group (N=23; 47.6+9.9 years; 94.1% female; 33.2+4.5 kg/m2); (2) or wait-list control group (N=17; 42.6+8.9 years; 86.9% female; 31.7+4.9 kg/m2). The intervention group received a theory-based, internet-delivered programme, a portable pedal machine at work and a pedometer for 12 weeks. The wait-list control group maintained their behaviours for 12 weeks. Outcome measures Primary (sedentary and physical activity behaviour measured objectively through StepWatch) and secondary (heart rate, blood pressure, height, weight, waist circumference, per cent body fat, cardiorespiratory fitness, fasting lipids) outcomes were measured at baseline and postintervention (12 weeks). Exploratory outcomes including intervention compliance and process evaluation measures were also assessed postintervention. Results Compared to controls, the intervention group reduced daily sedentary time (mean change (95%CI): −58.7 min/day (−118.4 to 0.99; p<0.01)) after adjusting for baseline values and monitor wear time. Intervention participants logged on to the website 71.3% of all intervention days, used the pedal machine 37.7% of all working intervention days and pedalled an average of 31.1 min/day. Conclusions These findings suggest that the intervention was engaging and resulted in reductions in daily sedentary time among full-time sedentary employees. These findings hold public health significance due to the growing number of sedentary jobs and the potential of these technologies in large-scale worksite programmes. Trial Registration ClinicalTrials.gov #NCT01371084.

Mammographic Density Change with 1 Year of Aerobic Exercise among Postmenopausal Women: A Randomized Controlled Trial

Background: The Alberta Physical Activity and Breast Cancer Prevention (ALPHA) Trial examined the influence of aerobic exercise on biological factors that are associated with breast cancer risk. Mammographic density, a secondary outcome, is reported here. Methods: The ALPHA Trial was a parallel group randomized controlled trial conducted between May 2003 and July 2007. Postmenopausal, sedentary women ages 50 to 74 years (n = 320) were evenly randomized to aerobic exercise (45 minutes, 5 days per week) or control (usual life-style) for 1 year. Dense fibroglandular tissue and nondense fatty tissue were measured from mammograms at baseline and 1 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. Results: 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 ≥ 0.26). Conclusions: Achieving 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. Cancer Epidemiol Biomarkers Prev; 19(4); 1112–21. ©2010 AACR.

Understanding physical activity maintenance in breast cancer survivors.

OBJECTIVES To examine predictors of physical activity (PA) 6 months after a randomized controlled trial. METHODS Breast cancer survivors (N=377) completed assessments at baseline, postintervention, and 6 months after the intervention. Data were collected on demographic, medical, psychosocial, motivational, and behavioral variables at baseline, postintervention, and 6 months. RESULTS Survivors meeting PA guidelines at baseline (OR = 5.54, 95% CI = 2.99-9.82, P < 0.001) and postintervention (OR = 2.92, 95% CI = 1.63-5.23, P < 0.001) had a greater likelihood of meeting PA guidelines at 6 months follow-up. CONCLUSIONS Interventions promoting PA maintenance should focus on optimizing PA behavior, psychosocial functioning, and motivation.

Physical activity promotion among oncology nurses.

Background: Oncology nurses may be influential for providing physical activity guidance to cancer patients. Objective: The purposes of this study were to examine physical activity promotion practices of oncology nurses and to explore nurses’ perceived benefits of physical activity for cancer patients and barriers to physical activity promotion. Methods: Two thousand e-mails were sent by a data service company to a random selection of oncology nurses throughout the United States with a link to a Web-based survey. To be eligible, nurses had to be currently seeing patients. Results: Completed surveys were received from 274 oncology nurses. Most participants inquired about physical activity on at least some office visits (74.9%) and gave physical activity recommendations to 65.7% and 66.9% of on-treatment and posttreatment patients. “Lack of time” and that “patients are not interested” were the most prominent barriers identified by nurses, whereas perceived benefits for patients were rated favorably, with the exception of “reducing risk of recurrence.” Almost all perceived benefits and barriers were correlated with physical activity promotion, with the strongest correlates being “unsure what to recommend” and “unsure that physical activity is safe.” Conclusions: Although most oncology nurses frequently inquire about patient physical activity, they may be less apt to provide recommendations. A number of barriers and perceived benefits may influence physical activity promotion, especially concerning what to recommend and patient safety. Implications for Practice: Oncology nurses would benefit from education opportunities about the benefits of physical activity for survival outcomes and types of physical activity to recommend.